
[Federal Register Volume 75, Number 81 (Wednesday, April 28, 2010)]
[Proposed Rules]
[Pages 22470-22496]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-9363]



[[Page 22469]]

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Part III





Environmental Protection Agency





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40 CFR Parts 9 and 63



National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore 
Processing and Production Area Source Category and Addition to Source 
Category List for Standards; Proposed Rule

  Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / 
Proposed Rules  

[[Page 22470]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 9 and 63

[EPA-HQ-OAR-2010-0239; FRL-9140-7]
RIN 2060-AP48


National Emission Standards for Hazardous Air Pollutants: Gold 
Mine Ore Processing and Production Area Source Category and Addition to 
Source Category List for Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to add the gold mine ore processing and 
production area source category to the list of source categories 
subject to regulation under the hazardous air pollutant section of the 
Clean Air Act (CAA) due to their mercury emissions. EPA is also 
proposing national mercury emission standards for this category based 
on the emissions level of the best performing facilities which are well 
controlled for mercury. EPA is soliciting comments on all aspects of 
this proposed rule.

DATES: Comments must be received on or before May 28, 2010 unless a 
public hearing is requested by May 10, 2010. If a hearing is requested 
on this proposed rule, written comments must be received by June 14, 
2010. Under the Paperwork Reduction Act, comments on the information 
collection provisions must be received by the Office of Management and 
Budget (OMB) on or before May 28, 2010.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2010-0239, by one of the following methods:
     Follow the on-line instructions for submitting comments at 
the following Web address: http://www.regulations.gov.
     E-mail: Comments may be sent by electronic mail (e-mail) 
to a-and-r-Docket@epa.gov, Attention Docket ID No. EPA-HQ-OAR-2010-
0239.
     Fax: Fax your comments to: (202) 566-9744, Attention 
Docket ID No. EPA-HQ-OAR-2010-0239.
     Mail: Send your comments to: Air and Radiation Docket and 
Information Center, Environmental Protection Agency, Mailcode: 2822T, 
1200 Pennsylvania Ave., NW., Washington, DC 20460, Attention: Docket ID 
No. EPA-HQ-OAR-2010-0239. Please include a total of two copies. In 
addition, please mail a copy of your comments on the information 
collection provisions to the Office of Information and Regulatory 
Affairs, Office of Management and Budget (OMB), Attn: Desk Officer for 
EPA, 725 17th St., NW., Washington, DC 20503.
     Hand Delivery or Courier: Deliver your comments to EPA 
Docket Center, Room 3334, 1301 Constitution Ave., NW., Washington, DC 
20460. Such deliveries are only accepted during the Docket Center's 
normal hours of operation, and special arrangements should be made for 
deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2010-0239. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
confidential business information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means that EPA will not know 
your identity or contact information unless you provide it in the body 
of your comment. If you send an e-mail comment directly to EPA without 
going through http://www.regulations.gov, your e-mail address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and will be made available on the Internet. 
If you submit an electronic comment, EPA recommends that you include 
your name and other contact information in the body of your comment and 
with any disk or CD-ROM you submit. If EPA cannot read your comment due 
to technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available (e.g., CBI or other information 
whose disclosure is restricted by statute). Certain other material, 
such as copyrighted material, will be publicly available only in hard 
copy form. Publicly available docket materials are available either 
electronically in http://www.regulations.gov or in hard copy at the EPA 
Docket Center, Public Reading Room, EPA West, Room 3334, 1301 
Constitution Ave., NW., Washington, DC. The Public Reading Room is open 
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal 
holidays. The telephone number for the Public Reading Room is (202) 
566-1744, and the telephone number for the Air Docket is (202) 566-
1742.

FOR FURTHER INFORMATION CONTACT: For questions about these proposed 
standards for gold mine ore processing and production, contact Mr. 
Chuck French, Sector Policies and Program Division, Office of Air 
Quality Planning and Standards (D243-02), Environmental Protection 
Agency, Research Triangle Park, North Carolina 27711, telephone number 
(919) 541-7912; fax number (919) 541-3207, e-mail address: 
french.chuck@epa.gov.

SUPPLEMENTARY INFORMATION: The information presented in this preamble 
is organized as follows:

I. General Information
    A. Does this action apply to me?
    B. What should I consider as I prepare my comments to EPA?
    C. Where can I get a copy of this document?
    D. When would a public hearing occur?
II. Addition to Section 112(c)(6) Source Category List
III. Background Information
    A. What is the statutory authority and regulatory approach for 
the proposed standards?
    B. What source category is affected by the proposed NESHAP?
    C. What are the production operations, emission sources, and 
available controls?
IV. Summary of the Proposed Standards
    A. Do these proposed standards apply to my facility?
    B. When must I comply with the proposed standards?
    C. What are the proposed standards?
    D. What are the testing and monitoring requirements?
    E. What are the notification, recordkeeping, and reporting 
requirements?
    F. What are the title V permit requirements?
    G. Emissions of Non-Mercury HAPs
    H. Request for Comments
V. Rationale for the Proposed Standards
    A. How did we select the affected source?
    B. How did we determine MACT?
    C. How did we select the testing, monitoring, and electronic 
reporting requirements?
VI. Impacts of the Proposed Standards
    A. What are the emissions, cost, economic, and non-air 
environmental impacts?
    B. What are the health benefits of reducing mercury emissions?
VII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act

[[Page 22471]]

    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. General Information

A. Does this action apply to me?

    The regulated categories and entities potentially affected by the 
proposed standards include:

------------------------------------------------------------------------
                                                         Examples of
             Category               NAICS Code \1\   regulated entities
------------------------------------------------------------------------
Industry:
    Gold Ore Mining...............          212221  Establishments
                                                     primarily engaged
                                                     in developing the
                                                     mine site, mining,
                                                     and/or
                                                     beneficiating
                                                     (i.e., preparing)
                                                     ores valued chiefly
                                                     for their gold
                                                     content.
                                                     Establishments
                                                     primarily engaged
                                                     in transformation
                                                     of the gold into
                                                     bullion or dore bar
                                                     in combination with
                                                     mining activities
                                                     are included in
                                                     this industry.
------------------------------------------------------------------------
\1\ North American Industry Classification System.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by this 
action. To determine whether your facility would be regulated by this 
action, you should examine the applicability criteria in 40 CFR 
63.11640 of subpart EEEEEEE (National Emission Standards for Hazardous 
Air Pollutants: Gold Mine Ore Processing and Production Area Source 
Category). If you have any questions regarding the applicability of 
this action to a particular entity, consult either the air permit 
authority for the entity or your EPA Regional representative, as listed 
in 40 CFR 63.13 of subpart A (General Provisions).

B. What should I consider as I prepare my comments to EPA?

    Do not submit CBI to EPA through http://www.regulations.gov or e-
mail. Send or deliver information identified as CBI only to the 
following address: Roberto Morales, OAQPS Document Control Officer 
(C404-02), Office of Air Quality Planning and Standards, Environmental 
Protection Agency, Research Triangle Park, NC 27711, Attention: Docket 
ID No. EPA-HQ-OAR-2010-0239. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI contained in a disk or 
CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as 
CBI and then identify electronically within the disk or CD-ROM the 
specific information that is claimed as CBI. In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2.

C. Where can I get a copy of this document?

    In addition to being available in the docket, an electronic copy of 
this proposed action will also be available on the Worldwide Web (WWW) 
through the Technology Transfer Network (TTN). Following signature, a 
copy of the proposed action will be posted on the TTN's policy and 
guidance page for newly proposed or promulgated rules at the following 
address: http://www.epa.gov/ttn/oarpg/. The TTN provides information 
and technology exchange in various areas of air pollution control.

D. When would a public hearing occur?

    If anyone contacts EPA requesting to speak at a public hearing 
concerning this proposed rule by May 10, 2010, a public hearing will be 
held on May 13, 2010. If you are interested in attending the public 
hearing, contact Ms. Pamela Garrett, Metals and Minerals Group (D243-
02), Sector Policies and Programs Division, U.S. EPA, Research Triangle 
Park, NC 27711, telephone (919) 541-7966 e-mail address: 
garrett.pamela@epa.gov to verify that a hearing will be held. If a 
public hearing is held, it will be held at EPA's campus located at 109 
T.W. Alexander Drive in Research Triangle Park, NC, or an alternate 
site. If a hearing is requested by May 10, 2010, any persons interested 
in presenting oral testimony at that hearing should contact Ms. Pamela 
Garrett at least 2 days in advance of the date of the public hearing.

II. Addition to Section 112(c)(6) Source Category List

    Section 112(c)(6) of the CAA requires that EPA list categories and 
subcategories of sources assuring that sources accounting for not less 
than 90 percent of the aggregate emissions of each of the seven 
specified Hazardous Air Pollutants (HAP) are subject to standards under 
section 112(d)(2) or (d)(4). The seven HAP specified in section 
112(c)(6) are as follows: alkylated lead compounds, polycyclic organic 
matter, hexachlorobenzene, mercury, polychlorinated biphenyls, 2,3,7,9-
tetrachlorodibenzofurans, and 2,3,7,8-tetrachloridibenzo-p-dioxin.
    In 1998, EPA published a list of section 112(c)(6) categories (63 
FR 17838, April 10, 1998). At that time, there was very little 
available information on mercury emissions from gold mine ore 
production and processing. Since the 1998 notice, a substantial amount 
of data and information have become available on mercury emissions from 
this source category. For example, in 2000, the first estimates of 
mercury emissions from this source category were published in the 
Toxics Release Inventory (TRI), largely because of the lower TRI 
reporting threshold for mercury that went into effect about that time. 
Following this, from 2001 to 2005, additional data and information were 
collected through the Voluntary Mercury Reduction Program (VMRP), which 
was a collaborative agreement between the State of Nevada Division of 
Environmental Protection (NDEP), EPA's Region 9 Office, and four gold 
mining companies. Then, in 2005-2006 the EPA's Office of Air Quality 
Planning and Standards (OAQPS) and the NDEP sent questionnaires to a 
number of companies seeking additional information and data on mercury 
emissions. Moreover, starting in 2007 the NDEP has been requiring all 
facilities in Nevada to conduct annual mercury emissions tests. Based 
on these data collected over the past several years, along with 
information about the industry processing and production levels and 
activities in the early 1990s, EPA has estimated that the gold mine ore 
processing and production emitted about 4.4 tons of mercury during the

[[Page 22472]]

baseline year (i.e., in 1990). These estimated mercury emissions in the 
1990 inventory for gold mine ore processing and production are based on 
emissions from the following thermal processes at gold mine ore 
processing and production facilities: roasters, autoclaves, carbon 
kilns, pregnant storage solution tanks (``preg tanks''), 
electrowinning, melt furnaces, and retorts. We have updated our 1990 
baseline emission inventory for section 112(c)(6) to reflect this 
contribution of mercury from gold mine ore processing and production 
and determined that this area source category contributed to the 90 
percent of the aggregate emissions of mercury in 1990. Consequently, we 
are adding the gold mine ore processing and production area source 
category to the list of source categories under section 112(c)(6) on 
the basis of mercury emissions.

III. Background Information

A. What is the statutory authority and regulatory approach for the 
proposed standards?

    As mentioned above, CAA section 112(c)(6) requires that EPA set 
standards under section 112(d)(2) or (d)(4). The mercury standards for 
the gold mine ore processing and production area source category are 
being established under CAA section 112(d)(2), which requires MACT 
level of control. Under CAA section 112(d), the MACT standards for 
existing sources must be at least as stringent as the average emissions 
limitation achieved by the best performing 12 percent of existing 
sources (for which the administrator has emissions information) for 
source categories and subcategories with 30 or more sources, or the 
best performing 5 sources for categories and subcategories with fewer 
than 30 sources (CAA section 112(d)(3)(A) and (B)). This level of 
minimum stringency is called the MACT floor. For new sources, MACT 
standards must be at least as stringent as the emission control that is 
achieved in practice by the best controlled similar source (CAA section 
112(d)(3)). EPA also must consider more stringent ``beyond-the-floor'' 
control options. When considering beyond-the-floor options, EPA must 
consider not only the maximum degree of reduction in emissions of HAP, 
but must take into account costs, energy, and nonair quality health and 
environmental impacts when doing so.

B. What source category is affected by the proposed NESHAP?

    The gold mine ore processing and production area source category 
consists of facilities engaged in processing gold ore to recover gold 
using one or more of the following process units: roasters, autoclaves, 
carbon kilns, melt furnaces, mercury retorts, electrowinning, and/or 
pregnant solution tanks. There were approximately 21 gold mine ore 
processing and production facilities operating these processes in the 
United States (U.S.) in 2008. The majority and the largest of these 
facilities are located in Nevada. The other facilities currently 
operating are in Alaska, California, Colorado, Montana, and Washington. 
In 2007, the U.S. gold mine industry produced about 240 metric tons of 
gold, and the value of gold mine production was about $5.1 billion.

C. What are the production operations, mercury emission sources, and 
available controls?

    All gold mine operations in the U.S. begin by mining ores, 
generally using large earth moving equipment. The ore is then subject 
to crushing operations. After crushing, some ore may be pre-treated by 
roasting or autoclaving. Subsequent to these operations the ore 
undergoes some type of leaching process using a dilute cyanide 
solution. The cyanide binds with the gold (and various impurities 
including mercury) to produce a ``pregnant'' solution. The pregnant 
solutions are further processed using various thermal processes (e.g., 
electrowinning, retorts and furnaces) to recover gold. The gold mine 
ore processing and production area source category covers the thermal 
processes that occur after the crushing, including roasting operations 
(i.e., ore dry grinding, ore preheating, roasting, and quenching), 
autoclaves, carbon kilns, electrowinning, preg tanks, retorts and 
furnaces. Further details of the gold production processes are 
described in section C.2 below.
1. Historical Background on Mercury Emissions
    Mercury, which is naturally present in the ores in various 
concentrations, enters the gold recovery processes with the gold mine 
ore. Most of this mercury is recovered as a by-product in the form of 
liquid elemental mercury, or as a mercury precipitate, placed in closed 
containers, and stored or sold to commercial metal companies. In 
addition, a notable amount of mercury is currently captured by mercury 
emission control devices (e.g., in carbon media) and is not recovered 
for sale. Nevertheless, some portion of the mercury in the ore is 
liberated to the air during the thermal processes resulting in mercury 
emissions to the atmosphere. Without emissions controls the potential 
for mercury emissions from these facilities would be quite high.
    In May 2000, EPA published the first estimates of mercury emissions 
for gold mine ore processing and production facilities as part of the 
EPA's TRI for year 1998. Total mercury air emissions reported to the 
TRI in the 1998-2001 timeframe for this source category were about 
14,000 pounds per year. However, EPA estimated (in the 1999 National 
Emissions Inventory) that total mercury emissions from this category 
were higher (about 23,000 pounds in 1999), and the mining industry 
reported emissions to be 21,000 pounds in 2001. Even at that time, some 
facilities had controls on processes to limit mercury emissions. Early 
efforts to reduce or limit mercury emissions were due in part to 
concerns about worker exposure to mercury. For example, for years 
facilities that were processing ores with higher levels of mercury have 
been using retorts to condense and capture the mercury in liquid 
elemental form. Moreover, two of the largest facilities have been using 
mercury specific emissions controls on their roasters since the mid-
1990s. Also, a number of facilities had carbon adsorption beds to 
control mercury emissions on various thermal process units prior to 
2001. We estimate that without these early controls the potential 
emissions would have been much higher than 23,000 pounds (at least 
37,000 pounds).
    Since 2001, mercury emissions from gold mine ore processing and 
production have been further reduced. The reductions achieved since 
2001 were obtained through programs implemented by the NDEP, EPA, and 
industry. The first program for reducing mercury emissions from these 
facilities was the Voluntary Mercury Reduction Program (VMRP). The VMRP 
was a voluntary partnership between the NDEP, EPA Region 9, and four 
large gold mining companies. The main goal of the VMRP, which was 
officially adopted in June 2002, was to achieve significant, permanent 
and rapid reductions in mercury air emissions from precious metal 
processing operations. The VMRP focused on 5 large facilities in Nevada 
that accounted for most of the reported emissions in 2001. Some mercury 
emission reductions were quickly achieved by adding emission controls 
to some of the thermal units that emit mercury at these facilities.
    To achieve further reductions in mercury emissions, the NDEP 
converted the VMRP into a regulatory program, called the Nevada Mercury 
Control Program (NMCP). As described on the NDEP Web site, the NMCP is 
a State

[[Page 22473]]

regulatory program that supersedes and replaces the VMRP and requires 
best available mercury emissions control technology on all thermal 
units located at all precious metal mines in Nevada. The NMCP was 
adopted March 8, 2006 and made effective May 4, 2006. The NMCP is a 
case-by-case permit program in 2 phases. The NMCP also had an early 
reduction program, which provided incentives for facilities to add 
controls within the first 2 years of the program (by mid-2008). A few 
facilities in Nevada took advantage of the early reduction program and 
added mercury specific controls (sulfur impregnated carbon filters) in 
2007 on various thermal units.
    In Phase 1 of the NMCP, which has recently been completed, permits 
were issued that require comprehensive work practice standards for the 
proper operation of existing mercury controls and the operations of the 
thermal units to minimize mercury emissions until specific controls are 
identified later under Phase 2 of the program. Phase 1 also required 
annual stack testing, site inspections and emissions reporting to 
collect data to assist in mercury emissions controls determinations in 
Phase 2. Emissions data collected in Phase 1 of the NMCP were used in 
the development of this proposed rule. Phase 2 has begun issuing 
permits and all permits are scheduled for issuance by the end of 
calendar year 2010. Implementation of controls will begin shortly after 
permit issuance. The Phase 2 permit process is a technology review and 
engineering analysis to determine the best available control technology 
and mercury emission limits. Controls and mercury emissions limits will 
be determined on a case-by-case analysis and will be unique to the 
individual unit (not universal for the unit type). The NMCP is a 
control-based program that will require thermal units in Nevada to have 
a best available mercury control technology installed. The NDEP and EPA 
have coordinated on the review and analyses of data on emissions, 
controls, and monitoring approaches for mercury emissions from this 
category, and collaborated to assure that the State program could co-
exist and provide an additional level of control for facilities in 
Nevada while working in concert with the proposed National standards.
    As described further below, several facilities already have 
effective mercury emissions controls in place on various thermal units. 
We expect that a number of other facilities will need to add mercury 
controls to comply with emissions limits set forth in this NESHAP, 
resulting in further emissions reductions from this category.
2. Description of Gold Mine Ore Processing and Production
    The gold mine ore processing and production source category 
consists of the following processes: roasting operations, autoclaves, 
carbon regeneration kilns, electrowinning cells, pregnant solution 
tanks, mercury retorts, and melt furnaces. Each facility may not have 
every one of these processes because there are different production 
paths that can be taken to recover gold from mine ore. Mercury can be 
emitted from each of these thermal processes. Some of these processes 
are already well controlled for mercury emissions; however, there are 
some process units at several plants that are only partly controlled or 
uncontrolled for mercury.
    The first step in gold mining is extracting the gold-containing 
ores from surface or undergrounds mines, generally by using large-scale 
earthmoving equipment. Samples of ore are examined to determine grade 
and metallurgical characteristics. Broken rock is marked by type for 
efficient processing. Based on its metallurgical makeup, the ore is 
delivered to the proper processing location. Low grade ore is roughly 
broken into small chunks, and high grade ore is delivered to a grinding 
mill, where the ore is pulverized to a powder (milled ore).
    Depending on its metallurgical and other characteristics, the ore 
may be pretreated in a roaster or autoclave prior to leaching, or it 
may be sent directly to a leaching circuit without pretreatment. The 
two main types of ore are oxide ore and refractory ore. If the process 
of cyanide leaching can extract most of the gold contained in an ore 
with no pretreatment, the ore is referred to as oxide ore; otherwise, 
the ore is described as refractory ore. Oxide ore is sent directly to 
the leaching circuit where cyanide is used to liberate the gold. 
However, refractory ores contain organic carbon and/or sulfide mineral 
grains which inhibit the efficient recovery of gold during cyanide 
leaching. Roasters and autoclaves are used to oxidize the ore and 
remove these components. Refractory ore containing carbon and sulfur is 
roasted to over 1000 [deg]F, burning off the sulfide and carbon. The 
product of this process, which is now basically an oxide ore, is routed 
to a leaching circuit. Sulfide refractory ore without carbon is 
oxidized in an autoclave to liberate the gold from sulfide minerals; 
then it is sent to a leaching circuit. At all facilities, the ores are 
eventually sent to some type of cyanide leaching process.
    Lower grade oxide ores generally undergo a heap leaching process, 
whereby the ore is spread over large areas and dilute cyanide solution 
is slowly dripped through and collected on liners and channels. During 
the leaching process, cyanide binds with gold and other elements 
(including mercury) producing a ``pregnant'' cyanide solution. At most 
facilities that use this process, the next step involves pumping the 
pregnant cyanide-gold solution to tanks with activated carbon where the 
gold is adsorbed (collected) out of solution onto the activated carbon, 
and the remaining cyanide solution is largely recycled. This carbon 
adsorption step that follows the cyanide leaching is generally referred 
to as the ``carbon-in-column'' process.
    Higher grade ores are generally milled. If the ore is a higher 
grade ``oxide ore,'' it is milled and then generally sent directly to 
carbon-in-leach processes where activated carbon is added along with 
the milled ore and cyanide solution in tanks where the cyanide-gold 
complexes adsorb onto activated carbon. In these units the leaching and 
carbon adsorption occur together. If the higher grade ore is a 
refractory ore, it is roasted or autoclaved first, then it is sent to 
carbon-in-leach processes.
    However, a few facilities do not use carbon. Instead, these 
facilities use a different, zinc precipitate process, which is 
described later in this preamble.
    At all the facilities that use a carbon adsorption process, the 
gold loaded carbon (which also contains mercury and other constituents) 
is moved into a vessel where the gold is chemically stripped from the 
carbon typically by using a concentrated caustic cyanide solution, 
producing a concentrated cyanide-gold solution. Gold (along with other 
metals and minerals) is drawn from this concentrated solution 
electrolytically (in electrowinning cells). The concentrate from the 
electrowinning cells is usually sent to a filter press to remove excess 
moisture and then to a retort followed by a melt furnace. However, some 
facilities do not have retorts. These facilities dry the concentrate 
and then feed it directly to the melt furnace. Either way, the gold is 
melted in furnaces into dore (pronounced ``doh-rey'') bars containing 
up to 90 percent gold. Dore bars are subsequently sent to an external 
refinery to be refined to bars of 99.9 percent or more pure gold. The 
processing steps are discussed in more detail below. For processing 
steps that emit mercury, the

[[Page 22474]]

discussion below also describes the points of mercury emissions and 
available controls for such emissions.
3. Pretreatment of Refractory Ore
    As mentioned above, refractory ores have to be pretreated by 
furnace oxidation (ore roasting) and/or pressure oxidation 
(autoclaving) before they can be ready for cyanide leaching.
    Roasting Operations. The roasting operations that are sources of 
mercury emissions include ore dry grinding where the ore is ground and 
dried, preheating prior to roasting, roasting, and quenching. The 
roaster is by far the process unit with the greatest potential for 
mercury emissions because of the large quantity of ore processed and 
the high roasting temperatures, which readily volatilize available 
mercury from the ore. The mercury concentrations in the roasted ores 
are high enough that elemental mercury can be recovered from the 
roaster exhaust gas by condensation. The emission potential of the 
ancillary roasting operations (dry grinding, pre-heating and quenching) 
are much less than those from the roaster because they are operated at 
much lower temperatures. Dry grinding of the ore prior to roasting is 
primarily a source of particulate matter (PM) emissions; consequently, 
baghouses are used for PM emission control. Ore preheaters used to 
raise the ore temperature to facilitate roasting are typically equipped 
with baghouses or wet scrubbers, which control particulate and some 
oxidized mercury. Emissions from quenching (when the roasted ore is 
cooled) are controlled by wet scrubbers, which remove particulate and 
some oxidized mercury.
    Ore roasting is a combustion process where the milled ore is 
oxidized in a fluidized bed roaster. During the combustion process, ore 
components that interfere with the cyanide leaching of gold are 
oxidized and therefore removed. As the ore exits the combustion 
chamber, it typically enters a quench process, where the temperature is 
reduced by contact with cooling water and the generation of steam. The 
steam from the quench process is used as a heat source in other 
processes at the mill, or may be sent directly to a cooling tower.
    There are three gold mine ore processing and production facilities 
that have a total of six roasters. The mercury emissions generated 
during roasting are mainly in gaseous elemental or oxidized forms of 
mercury. A very small portion of the mercury emitted is in particulate 
or particulate-bound form. Each of these roasters has complex gas 
treatment systems to control not only these forms of mercury, but also 
to control PM, sulfur dioxide (SO2), nitrogen oxides 
(NOX), and carbon monoxide (CO). The PM control devices 
remove particulate mercury and some oxidized mercury. A significant 
amount of the elemental mercury is removed and recovered by 
condensation (either in a condenser or gas cooling device), and the 
three facilities with roasters use mercuric chloride scrubbers. These 
scrubbers use a mercuric chloride scrubber liquor to complex with 
mercury in the exhaust gas to precipitate a mercurous chloride 
byproduct (calomel). These scrubbers are also referred to as ``calomel 
scrubbers.'' The calomel precipitate is subsequently removed and is 
either sent to electrowinning to recover the mercury, disposed of 
offsite as a waste material, or a portion may be chlorinated to create 
fresh mercuric chloride for the calomel scrubber liquor. An example of 
the emissions controls and gas treatment train for a roaster includes a 
hot gas electrostatic precipitator (ESP), wash tower, gas coolers, 
fluorine tower, wet ESP, calomel scrubber, acid plant (for removal of 
SO2 and conversion to sulfuric acid product), peroxide 
scrubber (to control NOX), and regenerative thermal oxidizer 
(for CO).
    Autoclaves. Autoclaves are pressure oxidation vessels that are used 
to pretreat ores to increase gold recovery by cyanide leaching. The 
milled ore is mixed with water to form a slurry, and is then acidified 
with sulfuric acid. The acidified slurry is then pumped into the 
autoclave vessel, where oxygen is used to increase the vessel pressure 
to over 300 pounds per square inch, and the slurry is heated to 350 
[deg]F to 430 [deg]F. The slurry is agitated in the reaction vessel and 
is then discharged to a pressure relief chamber. There the liquid 
content is flashed to steam, recovered, and returned to the pressurized 
segment of the vessel.
    Most mercury is present in the gold ore as mercury sulfide, and 
during autoclaving, the mercury sulfide combines with oxygen to form 
mercury sulfate, which dissociates to some degree in the slurry. 
Consequently, the mercury present in gaseous emissions from the 
autoclave is mainly in the oxidized form.
    Three facilities have a total of eight autoclaves. All of the 
autoclaves are equipped with wet venturi scrubbers, which remove most 
of the particulate mercury and a significant portion of the oxidized 
mercury present in the emissions. Venturi scrubbers have a specially 
designed ``throat'' that increases the gas speed through the throat and 
shears spray droplets to smaller sizes, which enhances mixing of the 
droplets and particles and increases coagulation and collection.
4. Leaching
    As mentioned above, leaching generally takes place either directly 
after crushing or milling, or after roasting or autoclaving. In heap 
leaching, a dilute alkaline cyanide solution is distributed onto 
crushed ore. The solution percolates through the ore, and the gold 
reacts with free cyanide to form soluble gold-cyanide complexes. The 
complexes migrate with the solution to an impermeable liner and flow to 
a collection pond.
    The solution containing the precious metals is called the 
``pregnant'' cyanide solution. During this process, mercury, also 
present in the ore, may be leached into the gold-cyanide solution.
    Refractory ores, which have been roasted or autoclaved, are 
generally leached in reaction vessels, referred to as vat leaching. 
Activated carbon adsorbent is usually added to the leach vessels to 
improve gold recovery. All five facilities in the U.S. that employ 
roasters and/or autoclaves add activated carbon to these leach vessels, 
where the leaching and carbon adsorption occur simultaneously in the 
tank. This is called the ``carbon-in-leach'' process.
5. Carbon Adsorption Process
    As mentioned above, after leaching, the most common path for 
recovering gold from the cyanide solution is carbon adsorption, where 
the gold complexes in the pregnant solution are concentrated through 
adsorption onto activated carbon. If mercury is present in the gold-
cyanide solution, it is also adsorbed onto the carbon. The gold-bearing 
solution may be extracted from the leaching process and subsequently 
introduced into a carbon adsorption column for concentration of the 
gold content (i.e., the carbon-in-column process), or carbon may be 
added into the leach process concurrent with leaching from the ore 
(i.e., the carbon-in-leach process). All of these carbon adsorption 
processes produce a ``loaded'' carbon, which contains gold and mercury 
(and some other metals such as copper) as adsorbed cyanide complexes.
6. Carbon Desorption Processes
    The loaded carbon is then separated from the rest of the solution 
or slurry by physical separation processes (such as with a screen). The 
remaining cyanide solution is now considered ``barren'' and can either 
be recycled back to the barren pond for use in the heap leaching 
process, sent directly to the tailings impoundment (if the cyanide

[[Page 22475]]

concentrations are low), or sent to a cyanide destruction process and 
then to a tailings impoundment once the cyanide levels are sufficiently 
low.
    The loaded carbon, which contains gold-cyanide complexes, mercury, 
and other metals, is stripped in a carbon strip tank to recover gold 
(and other metals) typically using a heated caustic cyanide solution. 
Adsorbed gold, as well as adsorbed silver, mercury, and other metals 
are stripped from the carbon through desorption under pressurized or 
atmospheric conditions, resulting in a more concentrated gold-
containing solution.
7. Description of Thermal Units Used After Carbon Desorption
    Carbon kilns. After gold has been removed from the activated carbon 
through the stripping process, the carbon is usually regenerated and 
then recycled back to the adsorption process. Regeneration is performed 
to regain the adsorption capacity of the carbon. Rotary kilns known as 
carbon kilns are used to regenerate the spent carbon. Because the 
carbon can be oxidized in the kiln if air is present in the heating 
chamber, steam is introduced to the kiln to prevent the infiltration of 
air. As the carbon moves through the carbon kiln, it is heated, and 
mercury and other remaining components are desorbed into the gas stream 
in the kiln. Regenerated carbon exits the kiln and is captured and 
quenched, and the gas stream is vented from the process, along with 
combustion gas from heating the kiln chamber. The off-gas, containing 
steam and mercury, is discharged to a pollution control device, such as 
a carbon adsorber. The potential for mercury emissions from carbon 
kilns is directly dependent on the mercury content of the stripped 
carbon and whether there is a carbon adsorber or other device to 
control mercury emissions.
    There are approximately 16 facilities with 18 carbon kilns. Most of 
these carbon kilns have installed carbon adsorption units to control 
mercury emissions, and some other facilities in Nevada have proposed in 
their State permit applications under the NMCP to install carbon 
adsorbers on their carbon kilns. One facility uses a hypochlorite 
scrubber on its carbon kiln which oxidizes the elemental mercury to a 
more soluble form and removes it as mercuric chloride.
    Pregnant storage solution tanks (``preg tanks''). The concentrated 
gold-containing solution that was stripped from the carbon is 
transferred to a preg tank, which serves as a storage and feed tank to 
the electrowinning process (discussed below). The concentrated solution 
also contains mercury, and mercury vapor can be emitted from the preg 
tank vent. Two facilities have installed carbon adsorbers on their preg 
tanks. In addition, five facilities in Nevada have proposed in their 
State permit applications under the NMCP to install carbon adsorbers on 
their preg tanks.
    Electrowinning cells. Recovery of gold, along with co-precipitated 
metals such as silver and mercury, from concentrated carbon strip 
solutions is performed in one of two ways: Electrowinning (the most 
common process) or precipitation with zinc powder (discussed below). 
Separation of gold through electrowinning is achieved by using an 
electric potential to plate the gold (and other metals present) in 
solution onto a cathode; steel wool is typically used as the plating 
surface because of the large surface area it provides for gold 
deposition. The plated cathode, or sponge, is then either removed from 
the electrowinning cell, so that the gold-bearing sludge-like material 
can be removed from the plated cathode, or the plated cathode can be 
left in the electrowinning (EW) cell, but the current is turned off and 
the remaining solution is drained out, then the material is removed 
from the plated cathode. Either way, once the current has stopped, the 
gold-bearing sludge-like material (known as ``EW concentrate'') is 
separated from the cathode by physical means (such as shaking). The 
gold-bearing EW concentrate is then ready for further processing. 
During electrowinning, elemental mercury can vaporize and escape from 
the cell with the other gases produced in the process; carbon 
adsorption filters are effective in controlling these mercury 
emissions.
    There are approximately 17 electrowinning units located at 14 
plants. Five facilities have installed carbon adsorbers to control 
mercury emissions from electrowinning. In addition, four facilities in 
Nevada have proposed in their State permit applications under the NMCP 
to install carbon adsorbers on their electrowinning units.
    Retorts. The EW concentrate may contain up to sixty weight percent 
gold, depending on the mercury content of the cyanide solution, the 
presence of other metals and minerals in the material, and the 
configuration of the gold recovery process. EW concentrate with 
significant mercury content is treated in a retort to remove mercury 
moisture and other impurities. In this process, the EW concentrate is 
placed in a pot or tray that is loaded into a heated oven under vacuum 
pressure, usually for 12 to 24 hours at 600 [deg]C to 700 [deg]C to 
remove up to 99 percent of the mercury. The EW concentrate is heated, 
mercury is vaporized and then pulled through a condenser where it 
condenses forming liquid mercury. The liquid mercury is recovered and 
sent through a tube into a collection vessel. The remaining gold and 
silver at the end of the retorting process typically contains less than 
1 percent mercury (e.g., 1,000 to 8,000 mg/kg). The condenser allows 
some mercury to discharge in the off gas, and a loss of 0.4 to 0.7 
percent of the mercury from the condenser has been reported. There are 
approximately 12 facilities that operate retorts, and all operate the 
retort with a condenser and a carbon adsorption filter. A properly 
designed and maintained carbon adsorption filter located downstream of 
the condenser is expected to capture about 95 percent of the mercury in 
the cooled gas.
    Melt furnaces. Smelting is the last step in gold mine ore 
processing and production before the gold is sent to an off-site 
commercial gold refinery. Even after retorting, the retorted gold 
mixture still contains some impurities, including small concentrations 
of base and ferrous metals, and some residual mercury. During this last 
step, the retorted gold mixture (or EW concentrate for facilities that 
do not have retorts) is melted in a refinery melt furnace, along with a 
flux material that preferentially absorbs impurities, to produce a 
purified commercial mixture of gold known as dore. The furnace is 
heated to approximately 1500 [deg]C. Most of the remaining mercury is 
volatilized in the melt furnace as elemental mercury or oxidized 
mercury. The dore melt is poured into bars, and any flux slag that 
hardens on the bars is removed with a mechanical chipper. The bars are 
then shipped to a commercial gold refinery, where they are further 
processed to produce gold bullion (99.9 percent pure gold).
    There are approximately 24 melt furnaces at 17 gold mine ore 
processing and production facilities. All of the melt furnaces are 
equipped with either fabric filters, ESPs, wet scrubbers, or a 
combination thereof to control emissions of PM. The wet scrubbers also 
remove most of the oxidized mercury, but do not remove elemental 
mercury. Six facilities have installed carbon adsorbers to control both 
oxidized and elemental mercury emissions from their melt furnaces. In 
addition, three facilities in Nevada have proposed in their State 
permit applications under NMCP to install carbon adsorbers on their 
melt furnaces.

[[Page 22476]]

8. Non-Carbon Concentrate Process
    After leaching, approximately four facilities recover the gold from 
the cyanide solution without using carbon by a process commonly known 
as the Merrill-Crowe (MC) method. The cyanide solution containing gold 
is separated from the ore by methods such as filtration and counter 
current decantation and clarified in special filters, usually coated 
with diatomaceous earth to produce a clarified solution. Zinc dust is 
then added to the clarified solution. Because zinc has a higher 
affinity for cyanide ions than does gold or other metals, zinc is 
dissolved and gold, silver, and mercury precipitate as a solid. The 
fine particulate metals are recovered by filtration processes. This 
process is performed in deoxygenated, enclosed reaction cells.
    The precipitate (also known as MC concentrate) is processed in 
retorts and melt furnaces, which are described above. The retorts and 
melt furnaces are the sources of mercury emissions at facilities that 
use non-carbon concentrate processes, and these processes are equipped 
with carbon adsorbers or venturi scrubbers to control mercury 
emissions. These facilities do not have carbon kilns since they do not 
use carbon.

IV. Summary of the Proposed Standards

A. Do these proposed standards apply to my facility?

    These proposed mercury standards would apply to gold mine ore 
processing and production facilities that are area sources that use any 
of the following thermal processes: Roasting operations, autoclaves, 
carbon kilns, preg tanks, electrowinning, retorts, and melt furnaces. 
Separate mercury standards are proposed for each of the following three 
affected sources: (1) Ore pretreatment processes (roasting operations 
and autoclaves), (2) carbon processes (carbon kilns, preg tanks, 
electrowinning, retorts, and melt furnaces at facilities that use 
carbon to recover the gold from the cyanide solution), and (3) non-
carbon concentrate processes (retorts and melt furnaces at facilities 
that do not use carbon to recover gold).
    We are proposing standards for both new and existing affected 
sources. An affected source is an existing source if construction or 
reconstruction commenced on or before April 28, 2010. An affected 
source is a new source if construction or reconstruction commenced 
after April 28, 2010.

B. When must I comply with the proposed standards?

    We are proposing that the owner or operator of an existing affected 
source comply with the final rule no later than 2 years after 
publication of that rule in the Federal Register. The owner or operator 
of a new affected source is required to comply by the date of 
publication of the final rule in the Federal Register or upon startup 
of the affected source, whichever occurs later.

C. What are the proposed standards?

    We are soliciting comments on all aspects of this proposed rule 
including, but not limited to, the data and calculations used to 
establish the emissions limits, the proposed testing and monitoring for 
emissions, and the parametric monitoring of control devices.
    The proposed standards are summarized in Table 1 of this preamble 
and discussed in more detail below. These proposed standards establish 
mercury MACT emission limits for three affected sources. The proposed 
MACT standard for new and existing ore pretreatment processes is 149 
pounds of mercury per million tons of ore processed (149 lb/million 
tons). The proposed MACT standard for existing carbon processes is 2.6 
pounds of mercury per ton of concentrate processed (2.6 lb/ton of 
concentrate), and for new carbon processes is 0.14 pounds of mercury 
per ton of concentrate (0.14 lb/ton of concentrate). Concentrate is the 
gold-bearing sludge material that is processed in retorts. For 
facilities without retorts, concentrate is the quantity processed in 
melt furnaces before any drying. For new carbon processes, we are 
proposing a compliance alternative of 97 percent control efficiency. 
This alternative provides at least equivalent HAP reductions as the 
MACT floor.

          Table 1--Summary of Proposed Mercury Emission Limits
------------------------------------------------------------------------
                                        Mercury emission limit
       Affected source       -------------------------------------------
                                 Existing source         New source
------------------------------------------------------------------------
Ore pretreatment processes..  149 lb/ton of ore...  149 lb/ton of ore.
Carbon processes............  2.6 lb/ton of         0.14 lb/ton of
                               concentrate.          concentrate or 97
                                                     percent reduction
                                                     in uncontrolled
                                                     emissions.
Non-carbon concentrate        0.25 lb/ton of        0.20 lb/ton of
 processes.                    concentrate.          concentrate.
------------------------------------------------------------------------

    The proposed MACT standard for existing non-carbon concentrate 
processes is 0.25 pounds of mercury per ton of concentrate processed 
(0.25 lb/ton of concentrate processed), and for new non-carbon 
concentrate processes is 0.20 lb/ton of concentrate processed.

D. What are the testing and monitoring requirements?

1. Testing for Compliance With Emission Limits
    Any stack that is a discharge point for any thermal process at a 
gold mine ore processing and production facility would be tested for 
mercury emissions based on the average of a minimum of three runs per 
stack at least once annually (i.e., once every four successive calendar 
quarters) using EPA Method 29 in Appendix A-8 to part 60, the Ontario 
Hydro Method (ASTM D6784-02, ``Standard Test Method for Elemental, 
Oxidized, Particle-Bound and Total Mercury in Flue Gas Generated from 
Coal-Fired Stationary Sources''), EPA Method 30A, or EPA Method 30B, 
both in Appendix A-8 to part 60.
    We are proposing that the initial compliance test for new sources 
be conducted within 180 days of the compliance date. The emissions for 
each process stack (in lb/hr) would be multiplied by the number of 
hours the process operated in the 6-month period following the 
compliance date to determine the total mercury emissions for the 
initial 6-month period. The process inputs used in the denominator of 
the emission limit, including ore and concentrate, would be measured 
and summed for each month to provide the total input (in tons) for the 
initial 6-

[[Page 22477]]

month period following the compliance date. The sum of the emissions 
(in lbs) for the 6-month period for all process units included in the 
affected source would be divided by the total input for the 6-month 
period to determine compliance with the emission limit. After the 
initial 6-month period, all the stacks for the thermal process units 
would be tested for mercury emissions annually.
    We are proposing that existing sources also conduct their initial 
compliance test within 180 days of their compliance date. The emissions 
for each process stack (in lb/hr) would be multiplied by the number of 
hours the process operated in the 6-month period following the initial 
compliance date to determine the emissions for the 6-month period. The 
emissions for each process stack would be recorded in total pounds of 
mercury for the 6-month period. The total mercury emissions for the 
affected source for the 6 months would be determined by summing the 
emissions for each process stack included in the affected source. The 
total emissions for the 6-month period for the affected source would be 
divided by the process input (concentrate or ore) for the 6-month 
period to determine compliance with the emission limit.
    After the initial 6-month period, all of the stacks for the thermal 
process units at new and existing sources would be tested for mercury 
emissions annually. The total mercury emissions and process inputs for 
each 12-month period would be calculated as described below to 
determine compliance with the emissions limit.
    The process inputs used in the denominator of the emission limit, 
including ore and concentrate, would be measured and summed to provide 
the total input (in tons) for each month. For facilities with ore 
pretreatment processes, the daily quantity of ore (in tons) would be 
determined either by calibrated weigh scales or by measuring volumetric 
flow rate and density and multiplying the two measurements. The daily 
totals would be summed for each calendar month to provide a monthly 
total for ore input. For facilities with carbon and/or non-carbon 
processes affected sources, each batch of concentrate would be weighed 
by scales, and the total of all batches would be summed for each 
calendar month to produce monthly weights of concentrate.
    Emissions in lb/million tons of ore for each affected source of ore 
pretreatment processes would be determined by summing the emissions for 
all units in the pre-treatment processes affected source for the 
appropriate time period (e.g., a 6-month period initially for new and 
existing sources and the 12-month periods thereafter) and dividing this 
sum of the emissions by the sum of the total ore processed (expressed 
in millions tons) in all processes at the affected source for the 
appropriate time period (i.e., 6 months or 12 months). Emissions in lb/
ton of concentrate for each affected source of carbon processes would 
be determined by dividing the sum of the emissions from all carbon 
processes at the affected source for the appropriate time period by the 
sum of the tons of concentrate processed at the affected source for 
each time period. Emissions in lb/ton of concentrate for each non-
carbon concentrate process affected source would be determined by 
dividing the sum of the emissions from all non-carbon concentrate 
process units at the affected source for each appropriate time period 
by the sum of the concentrate (expressed in tons) processed in all 
process units at the affected source for each time period.
    Mercury testing at both the inlet and outlet of all mercury 
emissions control devices is proposed for new affected sources with 
carbon processes that choose to demonstrate a 97 percent reduction in 
emissions. The inlet and outlet of every process unit's control device 
would be sampled, and the mercury emissions before and after control 
(in lb/hr) would be multiplied by each process unit's operating hours 
for the appropriate time period to determine the mercury emissions for 
the time period. The initial tests would be done within 180 days of the 
compliance date. For the first 6 months of operation, the inlet 
emissions for all process units would be calculated and summed and 
compared to the sum of the calculated outlet emissions for the 6-month 
period. After the initial 6 months, annual tests would be conducted and 
the calculations would be based on each 12 month period to determine 
the percent reduction in mercury emissions.
    We have also considered other procedures for calculating the 
mercury emission rate in pounds per ton of input to determine 
compliance for the ore pretreatment group and possibly for the carbon 
and non-carbon affected sources as well. For example, one approach for 
the ore pre-treatment processes would be to divide the measured 
emission rate (in pounds per hour) from the compliance test for each 
autoclave and roasting operation by the ore throughput (in tons per 
hour) for each autoclave and roasting operation as measured during the 
performance tests. The result would be emissions in pounds per ton of 
ore for each autoclave and roasting operation. Then the fraction of the 
total ore processed in the previous 12 months would be calculated for 
each roasting operation and autoclave, and the emissions from all 
autoclaves and roasting operations in the group would be calculated as 
the weighted average pounds per ton of ore to determine compliance 
(i.e., the sum of fraction of total ore throughput times the pounds per 
ton for each roasting operation and autoclave). With this approach, it 
would not be necessary to monitor, record, and use the annual operating 
hours for each unit to calculate emissions. A similar approach could 
possibly also be used for the carbon and non-carbon groups. We are 
requesting comment and supporting information on the advantages and 
disadvantages of this possible alternative procedure and the proposed 
procedure for determining compliance from the ore pretreatment 
processes and the other process groups.
2. Monitoring Requirements
    Roasters. We are proposing two options for monitoring roaster 
emissions: (1) Integrated sorbent trap mercury monitoring coupled with 
parametric monitoring of scrubbers and (2) monitoring using a 
continuous emission monitoring system (CEMS) for mercury. Both proposed 
monitoring options would require establishment of operating limits to 
detect and correct problems as soon as possible. An exceedance of an 
operating limit would trigger immediate corrective action and would 
require that the problem be corrected within 48 hours or that the feed 
of ore to the roaster be stopped.
    The first option for monitoring emissions from roasters would be to 
use the EPA Performance Specification (PS) 12B for integrated sorbent 
trap mercury monitoring on a periodic basis coupled with parametric 
monitoring of mercury scrubbers. We propose that under this option the 
facility will sample and analyze weekly for mercury concentration 
according to PS 12B. To determine appropriate sampling duration, we 
propose that the owner or operator review the available data from 
previous stack tests to determine the upper 99th percentile of the 
range of mercury concentrations in the exit stack gas. Based on this 
upper end of expected concentrations, the facility would select an 
appropriate sampling duration that is likely to provide a valid sample 
and not result in breakthrough of the sampling tubes. If breakthrough 
of the sampling tubes occurs, the facility would re-sample using a 
shorter sampling duration.
    We are proposing that the owner or operator of an affected source 
would establish an operating limit for mercury

[[Page 22478]]

concentration for PS 12B monitoring during the initial compliance test 
and maintain the mercury emissions below the established operating 
limit. The specific method and equation to be used to establish the 
operating limit are described in the proposed rule. If the operating 
limit is exceeded, the facility would report the exceedance as a 
deviation and take corrective actions within 48 hours to return the 
emissions control system back to proper operation.
    In addition, we are proposing as part of this first monitoring 
option (i.e., sorbent trap monitoring) that facilities with roasters 
and calomel-based mercury control systems (also referred to as 
``mercury scrubbers'') also establish operating limits for various 
control parameters described below during their annual mercury 
compliance stack test. We are proposing that each mercury scrubber be 
equipped with devices to monitor the scrubber liquor flow rate, 
scrubber pressure drop, and inlet gas temperature. Minimum operating 
limits for the scrubber liquor flow rate and pressure drop would be 
established based on the lowest average value measured during any of 
the three runs of a compliant performance test. A maximum inlet 
temperature would be established based on the highest temperature 
measured during any of the three runs of the compliance test. In 
addition to the parameters described above, we are proposing that the 
facility must also monitor the mercuric ion concentration and the 
chloride ion concentration four times per day or continuously monitor 
the oxidation reduction potential and pH. These monitored parameters 
would be maintained within the range specified by the scrubber's 
manufacturer or within an alternative range approved by the permitting 
authority. If any of the parameters are outside the specified range or 
limit, corrective action would be taken to bring the parameters back to 
the operating range or limit or else the facility would commence 
shutdown of the roaster.
    As mentioned above, we are including an alternative option for 
monitoring emissions from roasters, which is to install and operate a 
continuous emission monitoring system (CEMS) for mercury. Under this 
alternative option, facilities would not be required to do the 
parametric monitoring of the mercury scrubbers described above under 
the first option. A facility choosing the CEMS option would operate the 
mercury CEMS according to EPA Performance Specification (PS) 12A 
(except that calibration standards traceable to the National Institute 
of Standards and Technology (NIST) are not required). This exception is 
necessary because the mercury concentrations in the exhaust gases from 
roasters can be higher than the range of concentrations that are 
covered with the existing calibration standards traceable to NIST. The 
current calibration standards traceable to NIST do not apply to the 
full range of mercury concentrations that can be present in the exhaust 
gases from roasters. However, calibration standards are available from 
the manufacturers of mercury CEMS which can be used to calibrate these 
CEMS for monitoring of roasters.
    In addition to following PS 12A, the facility would perform a data 
accuracy assessment of the CEMS according to section 5 of Appendix F in 
part 60. We are proposing that the owner or operator would establish an 
operating limit for mercury concentration for the CEMS during a 
compliance test for the roaster stack and monitor the daily average 
mercury concentration in the roaster stack exhaust gas with the CEMS. 
The specific method and equation to be used to establish the operating 
limit are described in the proposed rule. If any daily average 
concentration as measured with the CEMS exceeds the operating limit, 
the facility would report the exceedance as a deviation and take 
corrective actions within 48 hours to return the emission control 
system back to proper operation. Regardless of whether deviations 
occur, the owner or operator of any facility with a roaster would 
submit a monitoring plan that includes quality assurance and quality 
control (QA/QC) procedures sufficient to demonstrate the accuracy of 
the CEMS. At a minimum, the QA/QC procedures would include daily 
calibrations and an annual accuracy test for the CEMS.
    For facilities that control roaster mercury emissions with mercury 
scrubbers, we are proposing not to require sorbent traps or mercury 
CEMs monitoring if a facility demonstrates that the mercury emissions 
from its roasters are consistently low and well controlled. 
Specifically, if a facility can demonstrate that mercury emissions from 
the roaster are less than 10 pounds of mercury per million tons of ore, 
then the facility would be allowed to discontinue the use of the 
sorbent trap or CEMS as described above. To demonstrate this, the 
facility would conduct three or more consecutive independent 
performance tests for mercury at least one month apart on the roaster 
exhaust stacks and show that emissions are less than 10 pounds per 
million tons of ore during normal operations for all tests. However, 
such a facility would be required to perform the parametric monitoring 
for mercury scrubbers and maintain parameters within the operating 
ranges established in accordance with the proposed rule. Also, the 
facility would continue to perform annual compliance tests of the 
roaster stack. Moreover, if there is an increase in the mercury 
concentration in the ore processed by the roaster that is higher than 
any concentration measured during the previous 12 months, then the 
facility would need to perform a compliance test within 30 days of the 
first day that the new ore is processed to determine whether the 
mercury emissions are still below 10 lbs per million tons of ore. If 
any subsequent performance compliance test indicates that the roaster 
is emitting more than 10 pounds of mercury per million tons of ore 
input, then the facility would be required to monitor the roaster 
emissions using the sorbent trap method or CEMS.
    Carbon Adsorbers. For process units (such as furnaces, kilns, 
retorts, electrowinning, and autoclaves) that control mercury emissions 
with a carbon adsorber, we are proposing three emissions monitoring 
options. One proposed option involves monitoring the mercury 
concentration at the exit of the carbon bed. A second option is based 
on sampling the carbon bed for mercury. The third option is based on 
changing out the carbon bed after a fixed period of time determined 
based on historical operating experience.
    For the first option (i.e., the exit concentration monitoring 
option), the mercury concentration would be measured periodically using 
a sorbent trap according to EPA Method 30B. An operating limit would be 
established through sorbent trap measurements obtained during the 
initial compliance test. The mercury concentration would be measured 
during each annual performance compliance test of each of the stacks 
for the carbon processes using Method 30B. An operating limit would be 
calculated from the average mercury concentration measured during the 
compliance test multiplied by a factor. The factor is the MACT emission 
limit for carbon processes divided by the sum of results of the 
compliance test for all units within the carbon processes affected 
source. Thereafter, if the established operating limit is exceeded, the 
exceedance would be reported as a deviation and corrective action would 
be triggered (e.g., replace the carbon in the bed). The specific 
equations to calculate the operating limit are described in the 
proposed rule. Initially, the facility would measure mercury 
concentration in the exit gas monthly using Method 30B. Once mercury

[[Page 22479]]

concentrations reach 50 percent of the operating limit, the facility 
would then need to perform weekly sampling and analysis using Method 
30B. When the concentration reaches 90 percent of the operating limit, 
to prevent an exceedance, the owner or operator would be expected to 
replace the carbon in the control device within 30 days (or before the 
operating limit is actually exceeded).
    The second proposed monitoring option, which is based on sampling 
the carbon bed for mercury, would require conducting an initial 
sampling of the carbon in the carbon bed 90 days after the replacement 
of the carbon to determine mercury loading. A representative sample 
would be collected from the carbon bed and analyzed using EPA Method 
7471A, and the depth to which the sampler is inserted would be 
recorded. Based upon sample results, a carbon loading would be 
calculated for the system, and sampling would be performed quarterly 
thereafter. When the carbon loading reaches 50 percent of the design 
capacity of the carbon, monthly sampling would be performed until 90 
percent of the carbon loading capacity is reached. The carbon would be 
removed and replaced with fresh carbon no later than 30 days after 
reaching 90 percent of capacity to ensure that the maximum mercury 
loading as recommended by the manufacturer is not exceeded.
    The third proposed option would start with one of the two previous 
options. After collecting at least two years of data under one of the 
options described above, a facility would establish a change out time 
for the carbon based on the two years of monitoring and could implement 
this periodic change out instead of sampling and analysis after 
approval by the permitting authority. However, if there is any 
significant change in the process, input materials, or mercury control 
system (e.g., an increase in operating rates or processing different 
ores with higher mercury levels) then sampling and analysis (according 
to the procedures in option 1 or option 2 described above) would be 
required within 30 days to re-establish the carbon change out time.
    We are also proposing that the inlet stream to carbon adsorbers 
applied to autoclaves, carbon kilns, melt furnaces, and retorts be 
monitored for temperature and that the inlet temperature be maintained 
below the maximum temperature established during the compliance tests. 
If the maximum temperature is exceeded, the owner or operator would 
analyze the outlet concentration using Method 30B within 30 days as 
described above. If the concentration is below 90 percent of the 
operating limit, the owner or operator could set a new temperature 
operating limit 10 [deg]F above the previous operating limit. On the 
other hand, if the concentration is more than 90 percent of the 
operating limit, the facility would take corrective action to reduce 
the temperature back down to below the maximum temperature recorded 
during compliance tests and then retest emissions using Method 30B. If 
the concentration is more than 90 percent of the operating limit based 
on this subsequent test, then the facility must replace the carbon.
    Wet scrubbers. For each wet scrubber, we are proposing that 
pressure drop and water flow rate be maintained at a minimum level 
based on measurements during the initial or subsequent compliance 
test(s).

E. What are the notification, recordkeeping, and reporting 
requirements?

    The owner or operator of an existing or new affected source would 
be required to comply with certain notification, recordkeeping, and 
reporting requirements of the NESHAP General Provisions (40 CFR part 
63, subpart A), which are identified in Table 1 of this proposed rule. 
Each owner or operator of an affected source would submit an Initial 
Notification according to the requirements in 40 CFR 63.9(a) through 
(d) and a Notification of Compliance Status according to the 
requirements in 40 CFR 63.9(h).
    Each owner or operator of an existing or new affected source would 
be required to keep records to document compliance with the mercury 
emission limits. Owners or operators of new and existing affected 
sources would maintain records of all monitoring data. Other records 
include monthly totals of ore quantity for ore pretreatment affected 
sources, monthly quantities of concentrate for all other affected 
sources, and monthly hours of operation for each process unit at each 
affected source.
    If a deviation from this rule's requirements occurs, an affected 
source would be required to submit a compliance report for that 
reporting period. The proposed rule specifies the information 
requirements for such compliance reports.
    We are also proposing to require electronic reporting of 
performance evaluation data collected using methods compatible with 
EPA's Electronic Reporting Tool (ERT). After December 31, 2011, within 
60 days after the date of completing each performance evaluation 
conducted to demonstrate compliance, the owner or operator would submit 
the test data to EPA by entering the data electronically into EPA's 
WebFIRE database through EPA's Central Data Exchange. The owner or 
operator of an affected facility would enter the test data into EPA's 
database using the ERT or other compatible electronic spreadsheet. Only 
performance evaluation data collected using methods compatible with ERT 
would be subject to this requirement to be submitted electronically 
into EPA's WebFIRE database.

F. What are the title V permit requirements?

    Under section 502(a) of the CAA, all major sources and certain 
other sources, including sources subject to section 112 standards, are 
required to operate in compliance with a title V permit. Today's 
proposal requires that gold mine ore processing and production area 
sources comply with the title V permitting requirements. However, 
section 502(a) of the CAA provides that the Administrator may exempt an 
area source category (in whole or in part) from title V if she/he 
determines that compliance with title V requirements is 
``impracticable, infeasible, or unnecessarily burdensome'' on such 
category. We are therefore soliciting comment on whether such an 
exemption is appropriate under section 502(a) for any particular 
sources in this category. Commenters should provide supporting data and 
rationale to explain the bases for their comments.\1\
---------------------------------------------------------------------------

    \1\ For the factors that EPA considers in evaluating whether to 
exercise the Agency's discretion to exempt area sources from title 
V, please see National Emission Standards for Hazardous Air 
Pollutants for Area Sources: Clay Ceramic Manufacturing, Glass 
Manufacturing, and Secondary Nonferrous Metal Processing; Proposed 
rule, 72 FR 53838, 53849-53853 (September 20, 2007).
---------------------------------------------------------------------------

G. Emissions of Non-Mercury HAPs

    EPA recently gathered data and evaluated emissions of other HAP, 
including cyanide and non-mercury metals. The data indicate that the 
gold mining processing and production category consists of only area 
sources (i.e., facilities that emit less than ten tons per year of any 
one HAP and less than 25 tons per year of any combination of HAP). 
However, a few facilities are close to the major source threshold due 
to hydrogen cyanide (HCN). For example, the largest facility emits an 
estimated 5 to 9 tons of HCN per year. Emissions of all other HAPs, 
including mercury, are individually significantly lower than the 10 ton 
per year threshold for a single HAP and the 25 ton per year threshold 
for a

[[Page 22480]]

combination of HAP. However, depending on how facilities manage their 
cyanide processes, EPA believes that cyanide emissions could 
potentially change a facility's status from area source to major 
source. Although EPA would develop MACT standards if it ever identified 
any major sources of gold mine ore processing and production, the MACT 
standards in today's proposal apply only to area sources because those 
are the only gold mine ore processing and production sources EPA has 
identified.
    In light of the above, we are considering including in today's 
NESHAP a provision under which sources may certify and demonstrate that 
they are area sources of gold mine ore processing and production. We 
would include in this area source NESHAP management practices for 
cyanide processes that we believe would effectively limit cyanide 
emissions and thus assure that sources maintain their area source 
status. To the extent sources were concerned about their HCN emissions, 
they could implement the management practices for cyanide processes 
specified in this rule and certify to the Agency that they had done so. 
Some management practices we are considering include: maintaining pH of 
cyanide leach solutions greater than nine; burying leach lines whenever 
practical and feasible; monitoring cyanide concentrations at the 
perimeter and in a downwind direction of main emission sources; not 
allowing puddles to form that are greater than 1 square meter on leach 
pads; and in locations that have the highest potential for concentrated 
emissions (e.g., mixing tanks, CIL tanks, loading stations) maintain 
HCN air concentrations below a prescribed level (e.g., 5 ppm).
    We request comment on whether we should include the proposal 
described above or some modification of it. We also request comment on 
effective management practices to limit cyanide emissions, including 
the practices described above as well as other approaches to manage 
cyanide emissions.

H. Request for Comments

    As mentioned previously, we are soliciting comments on all aspects 
of this proposed rule, including, but not limited to, the data and 
calculations used to establish the emissions limits for mercury, the 
proposed requirements and options for emissions testing and monitoring, 
the parametric monitoring options for control devices, title V permit 
requirements, and emissions of non-mercury HAPs.

V. Rationale for the Proposed Standards

A. How did we select the affected source?

    We are proposing individual MACT standards for each of the 
following three affected sources in the gold mine ore processing and 
production source category: ore pretreatment processes, carbon 
processes, and non-carbon concentrate processes. These three affected 
sources reflect the three primary different types of processes used in 
this source category to produce gold. Moreover, many gold mine ore 
processing and production facilities combine the emissions from 
multiple process units within a single affected source and route them 
to a single mercury emission control system and stack. Because we 
cannot determine the mercury emissions from individual process units 
that share a stack, it is difficult to establish emission standards for 
each process unit within an affected source. Setting MACT standards for 
each of the three affected sources accommodates the various stack and 
control configurations for the process units within an affected source. 
Emissions from all process units in the affected source would be summed 
to determine compliance with the proposed MACT standard for that 
affected source.
    As described above, the three affected sources differ in process 
operations, the sources of mercury entering the processes, and the 
nature of the emissions. Ore pretreatment processes include roasting 
operations (roasters, ore dryers, ore pre-heaters, and quenchers) and 
autoclaves that are used to pretreat refractory ore, which contains 
organic carbon and/or sulfide mineral grains that prevent the initial 
use of cyanide leaching to extract the gold effectively from the ore. 
Mercury enters these processes with the ore. The potential for mercury 
emissions from this affected source is directly related to the amount 
of ore processed in the autoclaves and roasters; the proposed standard 
for this affected source is therefore expressed in pounds of mercury 
emissions per million tons of ore processed (lb/million tons of ore).
    Carbon processes include carbon kilns, electrowinning cells, melt 
furnaces, retorts, and preg tanks at facilities that use carbon to 
recover gold from pregnant cyanide solution. In developing a proposed 
format for the emission limit for carbon processes, we examined the use 
of loaded carbon, concentrate, and gold production in the denominator 
of a pound per ton format. In other NESHAPs, we have typically used the 
amount of feed throughput or the amount of product produced in the 
denominator of the emission limit. For example, in the proposed 
revisions to the Portland cement NESHAP (74 FR 21136, May 6, 2009), we 
analyzed the data and developed the MACT floor in terms of pounds per 
million tons of feed to the kiln and subsequently converted the 
emission limit to a format of pounds per million tons of clinker (i.e., 
the product from the kiln). Although loaded carbon can be considered 
the ``primary feed,'' we discovered there were potential issues with 
its measurements (e.g., default values were used for density), we were 
unsure that the data from different facilities were comparable, and it 
was not a quantity that has been required to be reported under existing 
State regulatory programs. We rejected the use of gold produced because 
some facilities do not produce gold (they send the intermediate product 
to offsite refineries), some facilities produce more silver than gold, 
and the quantity of gold varies depending on the percent of gold in the 
product. The primary intermediate product that is common to all of the 
facilities with these carbon processes is the gold-bearing EW 
concentrate, which is the input to retorts or melt furnaces. Further, 
concentrate is closely related to the final product because it contains 
about 60 percent gold, and because of its value, it is carefully and 
accurately weighed and records of the quantities are kept. Concentrate 
is also required to be reported under the NDEP program, so we had 
comparable and reliable data from the different gold mine ore 
processing and production facilities. Consequently, we decided that the 
most appropriate format of the emission limit for the carbon processes 
is lb/ton of concentrate.
    For the reasons discussed above, we are proposing the concentrate 
format. However, we also considered using the amount of loaded carbon 
for the denominator of the emission limit format for carbon processes 
instead of concentrate, and we believe there may be merit in using 
loaded carbon as the denominator. Therefore, we are soliciting comments 
on the merits of both formats. In particular, we seek comments on 
whether loaded carbon or concentrate would be the better format for 
compliance determinations (e.g., accuracy and reliability of the 
measurements, availability of records) or for other reasons or factors, 
such as the processes present at a given plant, operating layout, or 
offsite shipments for processing. We are also requesting

[[Page 22481]]

comment on whether the quantity of concentrate should be determined on 
an ``as fed'' or dry basis, and if a dry basis, what methods could be 
used to determine dry weight accurately and reproducibly.
    Non-carbon concentrate processes include retorts and melt furnaces 
at facilities that use the Merrill Crowe process to produce gold. These 
affected sources do not use carbon to recover gold and the only thermal 
process units used to recover gold ore are retorts and furnaces. As 
described above, during the non-carbon processes, zinc dust is added to 
the cyanide solution after leaching to precipitate gold and other 
metals (including mercury). The precipitate (or ``MC concentrate'') is 
then processed in retorts and metal furnaces, liberating mercury from 
the concentrate. The potential mercury emissions are therefore directly 
related to the amount of concentrate processed; consequently for this 
reason and the merits of using concentrate as discussed above, the 
proposed standard for this affected source is expressed in lb/ton of 
concentrate.

B. How did we determine MACT?

1. Selection of MACT Floors for Existing Sources for the Three Affected 
Sources
    CAA section 112(d)(3)(B) requires that the MACT standards for 
existing sources be at least as stringent as the average emission 
limitation achieved by the best performing five sources (for which the 
Administrator has or could reasonably obtain emissions information) in 
a category with fewer than 30 sources. The gold mine ore processing and 
production source category consists of fewer than 30 sources. As 
mentioned above, we are proposing MACT standards for each of the 
following three affected sources: ore pretreatment processes, carbon 
processes, and non-carbon concentrate processes. We have mercury 
emissions data on ore pretreatment processes for all five facilities in 
the United States with ore pretreatment processes. We have mercury 
emissions data on carbon processes for 11 facilities and mercury 
emissions data on non-carbon concentrate processes for two facilities. 
Pursuant to section 112(d)(3), the MACT floor limits for existing ore 
pretreatment processes and carbon processes are based on the average 
emission limitation achieved by the best performing five facilities for 
each of these two affected sources, and the MACT floor limit for 
existing non-carbon concentrate processes are based on the average 
emission limitation achieved by the two facilities with such processes.
    To calculate the MACT floor limit for each of the affected sources, 
we established and ranked sources' emissions from lowest to highest. 
The data on which we based the limits are expressed in terms of pounds 
of mercury emitted per ton of input, where the gold mine ore is the 
input for the ore pretreatment processes and concentrate is the input 
for the carbon processes and the non-carbon concentrate processes.
    We used the emissions data for those best performing affected 
sources to determine the emission limits to be proposed, with an 
accounting for variability. EPA must exercise its judgment, based on an 
evaluation of the relevant factors and available data, to determine the 
level of emissions control that has been achieved by the best 
performing sources under variable conditions. The Court has recognized 
that EPA may consider variability in estimating the degree of emission 
reduction achieved by best-performing sources and in setting MACT 
floors. See Mossville Envt'l Action Now v. EPA, 370 F.3d 1232, 1241-42 
(DC Cir 2004) (holding EPA may consider emission variability in 
estimating performance achieved by best-performing sources and may set 
the floor at a level that a best-performing source can expect to meet 
``every day and under all operating conditions'').
    To calculate the achieved emission limit, including variability, we 
used the equation: \2\
---------------------------------------------------------------------------

    \2\ More details on the calculation of the MACT floor limits are 
given in the technical memo in the docket.
---------------------------------------------------------------------------

UPL = xp + t * (vT) \0.5\

Where:

UPL = upper prediction limit (99 percent),
xp = average of the best performing MACT pool sources,
t = Student's t-factor evaluated at 99 percent confidence, and
vT = total variance determined as the sum of the within-
source variance and the between-source variance.

    The between-source variance is the variance of the average of the 
best performing source averages. The within-source variance is the 
variance of the MACT source average considering ``m'' number of future 
individual test runs used to make up the average to determine 
compliance. We are proposing that a compliance test would be based on 
the average of three runs; consequently, the value of ``m'' used in the 
statistical analysis is 3. This value of ``m'' is used to reduce the 
variability to account for the lower variability when averaging of 
individual runs is used to determine compliance in the future. For 
example, if the average of three test runs is used to determine 
compliance (m=3), the variability based on 3-run averages is lower than 
the variability of the single run measurements in the data base, which 
results in a lower UPL for the 3-run average.
    Our MACT floor limit calculations are based primarily on mercury 
emissions data from annual testing that was required by NDEP for 2007 
and 2008. However, we used data from 2006 for an autoclave at a Nevada 
facility that was not tested in 2007 and did not operate in 2008. We 
also used data from 2009 to replace 2008 test data at one Nevada 
facility that was invalidated due to not following the procedures in 
the State's testing protocol. In addition, we used 2010 test data for a 
Nevada facility that installed new mercury emission controls on its 
roasters and resumed operation in late 2009. The tests that generated 
the data described above generally consisted of three runs per test per 
process at each facility. There were cases where 2007 results represent 
emissions before a control device was installed, and 2008 test results 
were after a mercury emission control device had been installed. In 
those cases, we used only the 2008 (controlled) test results to 
determine the top performing facilities. Emissions from the tests (in 
lb/hr) were multiplied by the number of hours the process operated in 
the calendar year and then divided by the process input rate for the 
year (in tons) to calculate the facility's performance for an affected 
source (expressed as lbs of mercury emissions per ton of input 
material).
    Source performance and the resulting MACT floor limits are 
summarized in Tables 2, 3, and 4, for ore pretreatment, carbon, and 
non-carbon concentrate processes, respectively.

            Table 2--MACT Floor Results for Ore Pretreatment
------------------------------------------------------------------------
                                                              Average
                                                            performance
                        Facility                            (lb/million
                                                             tons ore)
------------------------------------------------------------------------
A.......................................................              62
B.......................................................              64
C.......................................................              69
E.......................................................              90
D.......................................................             211
Average of top 5........................................              99
99% UPL existing (MACT Floor)...........................             175
99% UPL new (MACT Floor)................................             163
------------------------------------------------------------------------


[[Page 22482]]


            Table 3--MACT Floor Results for Carbon Processes
------------------------------------------------------------------------
                                                              Average
                                                            performance
                        Facility                              (lb/ton
                                                           concentrate)
------------------------------------------------------------------------
M.......................................................            0.06
N.......................................................            0.60
A.......................................................            1.5
H.......................................................            1.8
D.......................................................            2.9
F.......................................................            3.1
C.......................................................            3.7
I.......................................................            6.9
G.......................................................            9.7
B.......................................................           21
J.......................................................           39
Average of top 5........................................            1.4
99% UPL existing (MACT Floor)...........................            2.6
99% UPL new (MACT Floor)................................            0.14
------------------------------------------------------------------------


    Table 4--MACT Floor Results for Non-Carbon Concentrate Processes
------------------------------------------------------------------------
                                                              Average
                                                            performance
                        Facility                              (lb/ton
                                                           concentrate)
------------------------------------------------------------------------
K.......................................................            0.07
L.......................................................            0.11
Average of top 2........................................            0.09
99% UPL existing........................................            0.25
99% UPL new.............................................            0.20
------------------------------------------------------------------------

    The average emission rates for ore pretreatment and carbon 
processes from the top five facilities performing these processes are 
99 lbs/million tons ore and 1.4 lb/ton of concentrate, respectively. 
The average emission rate for non-carbon concentrate processes from the 
top two facilities performing these processes is 0.09 lb/ton of 
concentrate. As previously discussed above, we account for variability 
in setting floors, not only because variability is an element of 
performance, but also because it is reasonable to assess best 
performance over time. Here, for example, we know that the 2 to 5 
lowest emitting affected sources' emission estimates are averages and 
we expect that the actual emissions will vary over time. If we do not 
account for this variability, we would expect that even the sources 
that perform better than the floor on average would potentially exceed 
the floor emission levels part of the time.
    For the lowest emitting sources (2 to 5 sources, depending on the 
affected source), we calculated an average emission rate using the data 
from multiple test runs for multiple processes. The results are shown 
in Tables 2, 3, and 4 and represent the average performance of each 
source from the sum of the average emissions from all process units 
within the affected source. We then calculated the average performance 
of the lowest emitting sources and the variances of the emission rates 
for each process unit, which is a direct measure of the variability of 
the data set. This variability includes the run-to-run and year-to-year 
variability in the total mercury input to each process unit and 
variability of the sampling and analysis methods over the testing 
period, and it includes the variability resulting from site-to-site 
differences for the lowest emitters. We calculated the MACT floor based 
on the UPL (upper 99th percent) as described earlier from the average 
performance of the lowest emitting sources, Students t-factor, and the 
total variability, which was adjusted to account for the lower 
variability when using 3-run averages to determine compliance. Our 
calculations yield the following MACT floor limits for existing 
sources: 175 lbs/million tons of ore for ore pretreatment processes, 
2.6 lb/ton of concentrate for carbon processes, and 0.25 lbs/ton of 
concentrate for non-carbon concentrate processes.
    The technologies for achieving the MACT floor for existing ore 
pretreatment processes include mercury scrubbers on roasters and 
venturi scrubbers on autoclaves and ancillary roaster operations. The 
roasters and autoclaves at Facilities A, B, C, and E shown in Table 2 
above are already equipped with these controls. Our MACT floor analysis 
indicates that these facilities are achieving the MACT floor average of 
99 lb/million tons of ore. The analysis also indicates that an emission 
reduction will be needed for Facility D to achieve the MACT floor. 
Currently Facility D also has venturi scrubbers on its autoclaves; 
however, the emission control performance of these scrubbers will need 
to be improved to achieve the MACT floor.
    To achieve the MACT floor for existing carbon processes, we expect 
that facilities would need to install carbon adsorbers on all process 
units that do not already have them (i.e., carbon adsorbers for carbon 
kilns, electrowinning, preg tanks, retorts, and melt furnaces). Our 
MACT floor analysis indicates that only Facilities M and N in Table 3 
are achieving the MACT floor level of control; consequently, the other 
nine facilities in Table 3 are expected to have to install carbon 
adsorbers on all process units that do not already have them. The two 
top performing facilities (M and N) are fully equipped with carbon 
adsorbers (i.e., all of their process units are controlled by carbon 
adsorbers). Facility M also processes ore which has significantly lower 
mercury concentrations compared to the ore processed at most other 
facilities. We believe the combination of processing ore with low 
mercury content and the use of state-of-the-art mercury emission 
controls result in emissions at Facility M that are considerably lower 
than the other facilities.
    For the non-carbon concentrate processes, the MACT floor technology 
is the use of carbon adsorbers on retorts and melt furnaces. We expect 
that Facility L would probably need to install a carbon adsorber on 
their melt furnace to achieve the MACT floor.
2. Selection of New Source Floors for the Three Affected Sources
    CAA section 112(d)(3) requires that the MACT floor limit for new 
sources not be less stringent than the emission control that is 
achieved in practice by the best controlled similar source. Table 2 
above shows that Facility A has the lowest emission rate for ore 
pretreatment processes and is therefore considered the ``best 
controlled similar source'' for such processes. As previously 
mentioned, this facility is equipped with calomel scrubbers on roasters 
and venturi scrubbers on autoclaves. The emission rate for ore-
pretreatment processes at Facility A is 62 lbs/million tons ore, not 
accounting for variability. Applying the UPL formula discussed earlier 
to account for variability based on the emission test runs for all 
affected process units at the best performing ore pretreatment affected 
source (Facility A), we calculated the 99th percentile of performance, 
which results in a new source MACT level of 163 lb/million tons of ore 
for ore pre-treatment processes.
    Table 3 shows that Facility M has the lowest emission rate for 
carbon processes and is therefore considered the ``best controlled 
similar source'' for such processes. As previously mentioned, all 
carbon process units at Facility M are well controlled with carbon 
absorbers. The emission rate for carbon processes at Facility M is 0.06 
lb/ton of concentrate. After applying the UPL formula as described 
above to account for variability, the new source floor for carbon 
processes based on the 99th percentile of performance is 0.14 lb/ton of 
concentrate.
    For carbon processes at new sources, we are proposing a compliance 
alternative to provide flexibility in determining compliance because of 
the wide variety of process combinations and variations in input 
material that

[[Page 22483]]

may be present at future new carbon process sources. A well-established 
and conventional metric for expressing the degree of emission control 
is the percent control of the target pollutant. As mentioned above, 
Facility M is considered the ``best controlled similar source'' for 
carbon processes. Test data were available for 2007 for Facility M when 
the processes were uncontrolled, for 2008 when the controls were newly 
installed, and from 2009 after over one year of operation. The test 
results showed a 99.6 percent mercury emission reduction in 2008 and 
93.5 percent reduction in 2009. Based on these results and considering 
variability over time, we are proposing a compliance alternative of 97 
percent reduction in mercury emissions for new carbon processes. This 
compliance alternative was calculated based on the average reduction 
achieved by the best performing source in 2008 and 2009.
    Table 4 shows that Facility K has the lowest emission rate for non-
carbon concentrate processes and is therefore considered the ``best 
controlled similar source'' for such processes. The emission rate for 
non-carbon concentrate processes at Facility K is 0.07 lb/ton of 
concentrate (not accounting for variability). Again applying the UPL 
formula as described above to account for variability, the new source 
floor for non-carbon concentrate processes based on the 99th percentile 
of performance is 0.20 lb/ton of concentrate.
3. Beyond the Floor Determination
    To evaluate opportunities for emission reductions beyond those 
provided by the MACT floor, we typically identify control techniques 
that have the ability to achieve an emissions limit more stringent than 
the MACT floor. As mentioned above, the facilities with ore 
pretreatment processes would have installed mercury scrubbers and 
venturi scrubbers on their roasters and autoclaves, respectively, to 
achieve the MACT floor for ore pretreatment processes. To achieve 
further reductions in mercury beyond what can be achieved using mercury 
scrubbers and venturi scrubbers, we identified as a beyond-the-floor 
option the installation of both a refrigeration unit (or condenser) and 
a carbon adsorber on autoclaves. This additional control system would 
follow the existing venturi scrubbers to further reduce mercury 
emission from autoclaves. Because the exhaust is saturated with water, 
a refrigeration unit or condenser would be needed to remove water that 
would otherwise adversely affect the adsorptive capacity of the carbon 
adsorber. With this additional control system, all facilities with ore 
pretreatment processes could achieve an average performance of 90 lb/
million tons of ore or less. This is lower than the average emission 
rate of 99 lbs/million tons ore for ore pretreatment processes from the 
top five facilities performing these processes.
    In determining whether to control emissions ``beyond-the-floor,'' 
we must consider the costs, non-air quality health and environmental 
impacts, and energy requirements of such more stringent control. See 
CAA Section 112(d)(2). We estimate that the capital cost for the 
additional controls on the autoclaves would be $890,000 with a total 
annualized cost of $720,000/yr. Mercury emissions would be reduced by 
543 lbs, resulting in an estimated cost effectiveness of $1,300/lb. 
Energy consumption would increase by about 730 megawatt-hours per year, 
primarily due to the refrigeration unit. Solid waste generation and 
disposal (spent carbon loaded with mercury) would increase by about 3 
tons per year. (See Section VI.A for additional discussion of our 
consideration of emissions, cost, and non-air impacts in developing 
MACT standards for this source category.) After considering the costs 
and the above-mentioned impacts associated with the use of a 
refrigeration unit (or condenser) and a carbon adsorber on autoclaves, 
we believe that the emission reduction that can be achieved with this 
additional control system is justified under section 112(d) of the CAA. 
Applying the UPL formula discussed earlier to account for variability, 
the 99th percent UPL would be 149 lb/million tons of ore. We therefore 
propose that the beyond-the-floor performance level of 149 lb/million 
tons of ore is MACT for new and existing ore pretreatment processes.
    For the carbon processes, we estimate that 9 of the 11 facilities 
for which we have data will need to improve control to meet the floor 
limits because these 9 plants have an average emission control 
performance that is above the MACT floor average performance. There are 
a few facilities in the middle of the rankings that will probably only 
need marginal improvements, but several facilities (especially those at 
the bottom of the ranking that average several times the floor average) 
will need significant improvements in mercury emission control. We 
estimate that the MACT floor limit for the carbon processes will reduce 
emissions by about 1,100 lbs per year, a reduction of 89 percent from 
current levels. Our estimates of impacts for the MACT floor indicate 
that most of the carbon processes currently have or will have carbon 
adsorbers installed to effectively control mercury emissions at the 
MACT floor level. Considering the very low mercury concentrations when 
the carbon processes are performing at the MACT level of control, it is 
difficult to identify a technology that can obtain efficient additional 
percent reductions from low concentration streams. For a beyond-the-
floor analysis, we assumed that theoretically a second carbon 
adsorption system could be installed in series with the first one and 
would get an additional 90 percent reduction from the very low mercury 
concentrations that result from the MACT floor level of control. We 
acknowledge that there is uncertainty as to the additional percent 
reduction the second control system might achieve. Nevertheless, we 
estimate that the emission reduction would only be 12 lbs per year. The 
capital cost was estimated as $3.2 million with a total annualized cost 
of about $1.2 million/yr and a cost effectiveness of $100,000/lb. 
Considering the significant cost and the small additional reduction in 
emissions associated with a second carbon adsorption system and the 
uncertainty that even that small reduction might be achieved, we 
believe that the additional emission reduction from this beyond-the-
floor control option is not warranted under section 112(d).
    For the non-carbon concentrate processes, we expect that Facility L 
would probably need to add a carbon adsorber to its melt furnace to 
achieve the MACT floor level of control. For beyond the floor, we again 
assumed that the existing carbon adsorbers would be supplemented by 
adding a second control system of carbon adsorbers in series for all of 
the melt furnaces. We estimated the capital cost for the second set of 
control systems as $0.7 million and a total annualized cost of 
$306,000/year. Emissions would be reduced by 7 lb/year, which results 
in a cost effectiveness of $44,000/lb. Considering the very small 
emission reduction from a second carbon adsorber system, and its high 
capital and operating costs, we believe that the emission reduction 
associated with this additional control system is not warranted under 
section 112(d) of the CAA.

C. How did we select the testing, monitoring and electronic reporting 
requirements?

    We are proposing testing and monitoring requirements to assure 
compliance with the emission standards set forth in this proposed rule. 
These compliance assurance provisions are based, in part, on 
requirements that have been applied to this source category in State 
operating permits, EPA

[[Page 22484]]

requirements applied to other industries that emit mercury, and an 
understanding of how control devices and processes perform and can be 
effectively monitored.
    We are proposing initial compliance stack tests for mercury (using 
Method 29) within the first 180 days of the compliance date and annual 
compliance tests thereafter for all thermal process units to determine 
compliance with the proposed emission limits. The testing frequency and 
procedures would be essentially the same as the NDEP requirements for 
the facilities that are located in Nevada partly because the stack test 
data that we used to develop the proposed emission limits were based on 
the test methods applied in Nevada. To provide additional flexibility, 
we propose to allow the use of the Ontario Hydro Method, Method 30A, or 
Method 30B as alternatives to EPA Method 29.
    We also propose the following monitoring requirements to assure 
compliance with the proposed MACT standards.
    Roasters. In addition to the annual stack test, we are proposing 
two options for monitoring roaster emissions: (1) Integrated sorbent 
trap mercury monitoring coupled with parametric monitoring of scrubbers 
and (2) monitoring using a continuous emission monitoring system (CEMS) 
for mercury. Both proposed monitoring options would require 
establishment of operating limits to detect and correct problems as 
soon as possible. An exceedance of an operating limit for the sorbent 
trap or CEMS monitoring would trigger immediate corrective action and 
would require that the problem be corrected within 48 hours or that the 
feed of ore to the roaster be stopped.
    As part of this first monitoring option (i.e., sorbent trap 
monitoring), we are also proposing that facilities with roasters and 
mercury scrubbers establish operating limits for various parameters 
during their compliance test (i.e., the annual stack test for mercury 
emissions). The proposed parametric monitoring provides additional 
compliance assurance by ensuring that the process and control devices 
are operating properly. The proposed parameters for monitoring mercury 
scrubbers are similar to those currently required to be monitored in 
the title V operating permits issued by NDEP for roasters. We are 
proposing that each mercury scrubber be equipped with devices to 
monitor the scrubber liquor flow rate, scrubber pressure drop, and 
inlet gas temperature. Minimum operating limits for the scrubber liquor 
flow rate and pressure drop would be established based on the lowest 
average value measured during any of the three runs of a compliant 
performance test. A maximum inlet temperature would be established 
based on the highest temperature measured during any of the three runs 
of the compliance test. In addition to the parameters described above, 
we are proposing that the facility would also monitor the mercuric ion 
concentration and the chloride ion concentration four times per day or 
continuously monitor the oxidation reduction potential and pH. These 
monitored parameters would be maintained within the range specified by 
the scrubber's manufacturer or within an alternative range approved by 
the permitting authority. If any of the parameters are outside the 
specified range or limit, corrective action would be taken to bring the 
parameters back within the operating range or the facility would 
commence shutdown of the roaster.
    As mentioned above, we are including a mercury CEMS as an 
alternative for monitoring of mercury emissions from roasters. This 
monitoring option would not require parametric monitoring of the 
mercury scrubbers. Mercury CEMS have been applied at other industrial 
sources that emit mercury, such as coal-fired power plants and cement 
production plants, and these devices yield valuable information 
regarding continuous emissions performance. We realize that mercury 
CEMs have not yet been demonstrated on roasters at gold production 
facilities and that there are currently no calibration standards 
traceable to NIST within the range of mercury concentrations from 
roasters. However, calibration standards are available from the 
manufacturers of mercury CEMS. Based on the Agency's understanding and 
experience relative to continuous mercury monitoring at other 
industrial facilities, such as coal-fired power plants and cement 
plants, as well as research experience, EPA believes that the CEMS can 
be adequately calibrated with manufacturers' standards and be used as a 
valuable tool to monitor roasting operations to detect deviations in 
performance. We therefore believe that it is appropriate to propose the 
use of mercury CEMS as a monitoring option for roasters. However, we 
believe that it is appropriate to also propose an alternative 
monitoring approach based on frequent (weekly) monitoring using a 
sorbent trap method.
    We request comments on the viability of using mercury CEMs, 
specifically for monitoring mercury emissions from roasters at gold ore 
processing and production facilities. We request comments on 
calibration methods, costs, reliability and other aspects of the CEMs. 
We also request similar comments on the sorbent trap method.
    For facilities that control roaster mercury emissions with mercury 
scrubbers, we are proposing that if a facility demonstrates, in 
accordance with the demonstration requirements in the proposed rule, 
that mercury emissions from the roaster are less than 10 pounds of 
mercury per million tons of input ore, they can cease monitoring via 
either the sorbent trap or the mercury CEMS. Such a facility would be 
required to conduct the parametric monitoring for mercury scrubbers as 
described above (under option one) and maintain parameters within the 
operating ranges established in accordance with the proposed rule. 
Also, the facility would continue to perform annual compliance tests of 
the roaster stack to demonstrate emissions continue to be less than 10 
pounds of mercury per million tons of input ore. We believe that for 
roasters that are effectively controlled with mercury scrubbers (i.e., 
emitting less than 10 pounds per million tons of ore during normal 
operations), parametric monitoring of the scrubbers would be 
sufficient. This monitoring option provides additional incentive for 
facilities to reduce emissions from roasters. However, if any 
subsequent compliance tests indicate that the roaster is emitting more 
than 10 pounds of mercury per million tons of ore input, then the 
facility would be required to monitor the roaster emissions using a 
sorbent trap method or CEMS.
    We are specifically requesting comments on the advantages and 
disadvantages of the two options for monitoring emissions from roasters 
along with any supporting data and documentation to support one or both 
of the options. We are also requesting comment on the proposed daily 
averaging time when using the mercury CEMS option and the frequency of 
sampling when using the sorbent trap option. In addition, we are 
requesting comments on the proposed monitoring approach for low-
emitting roasters with mercury scrubbers, as described in the paragraph 
above, and possible alternatives to this approach. Moreover, we are 
requesting comments on the parametric monitoring methods.
    Carbon Adsorbers. For process units (such as furnaces, kilns, 
retorts, electrowinning, and autoclaves) that control mercury emissions 
with a carbon adsorber, we are proposing three options. One option 
involves monitoring the mercury concentration at the exit of the carbon 
bed. A second

[[Page 22485]]

option, adopted from requirements in some NDEP permits, is based on 
sampling the carbon bed for mercury. The third option is based on 
changing out the carbon bed after a fixed period of time determined 
based on historical operating experience.
    We believe that all three options could provide reasonable 
assurance that the carbon adsorber is operating properly on a 
continuing basis and that the carbon is replaced before breakthrough 
occurs. Our current preference among the three proposed monitoring 
options for carbon beds described above is the option of sampling the 
exit gas from the carbon bed using EPA Method 30B along with continuous 
temperature monitoring because this option provides a direct 
measurement of the amount of mercury exiting the control device. We are 
specifically requesting comments on the advantages and disadvantages of 
the three options along with any supporting data and documentation. 
Based on public comments, we intend to promulgate one or more of these 
options or a modified version as necessary.
    We are also proposing that the inlet stream to carbon adsorbers 
applied to autoclaves, carbon kilns, melt furnaces, and retorts be 
monitored for temperature and that the inlet temperature be maintained 
below the maximum temperature established during the compliance tests. 
We believe the temperature monitoring is needed to detect any 
excursions in mercury emissions caused by excessively high 
temperatures. We are also considering a reduction in frequency of the 
sampling and analysis based on historical data on the life of a new 
carbon bed (e.g., quarterly sampling when the carbon bed is fresh and 
monthly sampling after a specified period of time) and for processes 
that are very small sources of mercury emissions. We are requesting 
comments and supporting data on these options and others that may be 
appropriate for monitoring carbon beds.
    Wet scrubbers. For each wet scrubber, we are proposing that 
pressure drop and water flow rate be maintained at a minimum level 
based on measurements during the initial or subsequent compliance 
test(s). These parameters are the typical monitoring parameters 
required by other MACT standards and by State operating permits for wet 
scrubbers at gold mine ore processing and production facilities. 
Monitoring these parameters ensures that wet scrubbers are operating 
properly.
    Electronic reporting. The EPA must have performance test data to 
conduct effective reviews of CAA Section 112 and 129 standards, as well 
as for many other purposes including compliance determinations, 
emissions factor development, and annual emissions rate determinations. 
In conducting these required reviews, we have found it ineffective and 
time consuming not only for us but also for other regulatory agencies 
and source owners and operators to locate, collect, and submit 
emissions test data because of varied locations for data storage and 
varied data storage methods. One improvement that has occurred in 
recent years is the availability of stack test reports in electronic 
format as a replacement for cumbersome paper copies.
    In this action, we are taking a step to improve data accessibility. 
Owners and operators of affected facilities would be required to submit 
to an EPA electronic database an electronic copy of reports of certain 
performance tests required under this rule. Data entry would be through 
an electronic emissions test report structure called the Electronic 
Reporting Tool (ERT) that will be used by the staff as part of the 
emissions testing project. The ERT was developed with input from stack 
testing companies who generally collect and compile performance test 
data electronically and offices within State and local agencies which 
perform field test assessments. The ERT is currently available, and 
access to direct data submittal to EPA's electronic emissions database 
(WebFIRE) will become available by December 31, 2011.
    The requirement to submit source test data electronically to EPA 
would not require any additional performance testing and would apply to 
those performance tests conducted using test methods that are supported 
by ERT. The ERT contains a specific electronic data entry form for most 
of the commonly used EPA reference methods. The Web site listed below 
contains a listing of the pollutants and test methods supported by ERT. 
In addition, when a facility submits performance test data to WebFIRE, 
there would be no additional requirements for emissions test data 
compilation. Moreover, we believe industry would benefit from 
development of improved emissions factors, fewer follow-up information 
requests, and better regulation development as discussed below. The 
information to be reported is already required for the existing test 
methods and is necessary to evaluate the conformance to the test 
method.
    One major advantage of submitting source test data through the ERT 
is that it provides a standardized method to compile and store much of 
the documentation required to be reported by this rule while clearly 
stating what testing information we require. Another important benefit 
of submitting these data to EPA at the time the source test is 
conducted is that it will substantially reduce the effort involved in 
data collection activities in the future. Specifically, because EPA 
would already have adequate source category data to conduct residual 
risk assessments or technology reviews, there would likely be fewer or 
less substantial data collection requests (e.g., CAA Section 114 
letters). This results in a reduced burden on both affected facilities 
(in terms of reduced manpower to respond to data collection requests) 
and EPA (in terms of preparing and distributing data collection 
requests).
    State/local/Tribal agencies may also benefit in that their review 
may be more streamlined and accurate as the States will not have to re-
enter the data to assess the calculations and verify the data entry. 
Finally, another benefit of submitting these data to WebFIRE 
electronically is that these data will improve greatly the overall 
quality of the existing and new emissions factors by supplementing the 
pool of emissions test data upon which the emissions factor is based 
and by ensuring that data are more representative of current industry 
operational procedures. A common complaint we hear from industry and 
regulators is that emissions factors are outdated or not representative 
of a particular source category. Receiving and incorporating data for 
most performance tests will ensure that emissions factors, when 
updated, represent accurately the most current operational practices. 
In summary, receiving test data already collected for other purposes 
and using them in the emissions factors development program will save 
industry, State/local/Tribal agencies, and EPA time and money and work 
to improve the quality of emissions inventories and related regulatory 
decisions.
    As mentioned earlier, the electronic data base that will be used is 
EPA's WebFIRE, which is a Web site accessible through EPA's Technology 
Transfer Network (TTN). The WebFIRE Web site was constructed to store 
emissions test data for use in developing emissions factors. A 
description of the WebFIRE data base can be found at http://cfpub.epa.gov/oarweb/index.cfm?action=fire.main.
    The ERT will be able to transmit the electronic report through 
EPA's Central Data Exchange (CDX) network for storage in the WebFIRE 
data base. Although ERT is not the only electronic interface that can 
be used to submit source test data to the CDX for entry

[[Page 22486]]

into WebFIRE, it makes submittal of data very straightforward and easy. 
A description of the ERT can be found at http://www.epa.gov/ttn/chief/ert/ert_tool.html.

VI. Impacts of the Proposed Standards

A. What are the emissions, cost, economic, and non-air environmental 
impacts?

    We estimate the proposed MACT standard will reduce mercury 
emissions from gold mine ore processing and production by 1,650 lb/year 
from current emissions levels down to a level of 1,390 lb/year post-
MACT. The annual emissions expected after MACT (of 1,390 lbs) represent 
a 73 percent reduction from 2007 emissions (5,000 pounds), more than 90 
percent reduction from the emissions level in 2001 (about 23,000 
pounds), and more than 96 percent reduction from uncontrolled emissions 
levels (more than 37,000 pounds). The capital cost of emission controls 
is estimated as $5 million with a total annualized cost of $2.3 million 
per year. The capital costs for monitoring, reporting, and 
recordkeeping are estimated as $1.0 to $1.3 million with a total 
annualized cost of $0.8 to $1.5 million per year, depending on the 
monitoring option that is chosen. The cost of compliance is estimated 
to be less than 0.3 percent of sales. We therefore believe that the 
economic impact on an affected company would be insignificant. 
Electricity consumption is expected to increase by about 2,100 
megawatt-hours per year due to increased fan capacity for carbon 
adsorbers and the installation of refrigeration units or condensers on 
a few process units. Non-hazardous solid waste (spent carbon containing 
mercury that must be regenerated or disposed of) would increase by 
about 7 tons per year.

B. What are the health benefits of reducing mercury emissions?

    Mercury is emitted to the air from various man-made and natural 
sources. These emissions transport through the atmosphere and 
eventually deposit to land or water bodies. This deposition can occur 
locally, regionally, or globally, depending on the form of mercury 
emitted and other factors such as the weather. The form of mercury 
emitted varies depending on source type and other factors. Available 
data indicate that the majority of air emissions from gold mine ore 
processing and production facilities are in the form of gaseous 
elemental mercury. This form of mercury can be transported very long 
distances, even globally, to regions far from the emissions source 
(becoming part of the global ``pool'') before deposition occurs. 
However, this source category also emits some gaseous inorganic ionic 
mercury forms (such as mercuric chloride), and smaller amounts of 
particulate bound mercury. These forms have a shorter atmospheric 
lifetime and can deposit to land or water bodies closer to the 
emissions source. Furthermore, elemental mercury in the atmosphere can 
undergo transformation into ionic mercury, providing a significant 
pathway for deposition of emitted elemental mercury.
    As mentioned previously, the gold mine ore processing and 
production source category emitted about 2.5 tons of mercury to the air 
in 2007 in the U.S. Based on the EPA's National Emission Inventory, 
about 103 tons of mercury were emitted from all anthropogenic sources 
in the U.S. in 2005. Moreover, the United Nations has estimated that 
about 2100 tons were emitted worldwide by anthropogenic sources in 
2005.\3\ We believe that total mercury emissions in the U.S. and 
globally in 2007 were about the same magnitude as in 2005. Therefore, 
we estimate that in 2007 the gold mine ore processing and production 
source category emitted about 2.5 percent of the total anthropogenic 
mercury emissions in the U.S. and about 0.12 percent of the global 
emissions.
---------------------------------------------------------------------------

    \3\ United Nations Environment Programme/Arctic Monitoring and 
Assessment Program (UNEP/AMAP). Study on mercury-emitting sources, 
including emissions trends and cost and effectiveness of alternative 
control measures: ``UNEP Paragraph 29 study.'' 2008. Available at: 
http://www.chem.unep.ch/mercury/Paragraph29/Zero%20Draft%20Report%20March%208.doc.
---------------------------------------------------------------------------

    Potential exposure routes to mercury emissions include both direct 
inhalation, and consumption of fish containing methylmercury. The 
primary route of human exposure to mercury emissions from industrial 
sources is generally indirectly through the consumption of fish 
containing methylmercury. As described above, mercury that has been 
emitted to the air eventually settles into water bodies or onto land 
where it can either move directly or be leached into water bodies. Once 
deposited, certain microorganisms can change it into methylmercury, a 
highly toxic form that builds up in fish, shellfish and animals that 
eat fish. Consumption of fish and shellfish are the main sources of 
methylmercury exposure to humans. Methylmercury builds up more in some 
types of fish and shellfish than others. The levels of methylmercury in 
fish and shellfish vary widely depending on what they eat, how long 
they live and how high they are in the food chain. Most fish, including 
ocean species and local freshwater fish, contain some methylmercury. 
For example, in recent studies by EPA and the United States Geological 
Survey (USGS) of fish tissues, every fish sampled contained some 
methylmercury.\4\\, \\5\
---------------------------------------------------------------------------

    \4\ The National Study of Chemical Residues in Lake Fish Tissue. 
U.S. Environmental Protection Agency Office of Water Office of 
Science and Technology September 2009. Available at: http://www.epa.gov/waterscience/fish/study/index.htm.
    \5\ Scudder, B., L. Chasar, D. Wentz, N. Bauch, M. Brigham, P. 
Moran, and D. Krabbenhoft. (United States Geological Survey). 
Mercury in Fish, Bed Sediment, and Water from Streams Across the 
United States, 1998-2005. 2009. Available at: http://pubs.usgs.gov/sir/2009/5109/.
---------------------------------------------------------------------------

    Research shows that most people's fish consumption does not cause a 
mercury-related health concern. However, certain sub-populations may be 
at higher risk because of their routinely high consumption of fish 
(e.g., Tribal and other subsistence fishers and their families who rely 
heavily on fish for a substantial part of their diet). It has been 
demonstrated that high levels of methylmercury in the bloodstreams of 
unborn babies and young children may harm the developing nervous 
system, making the child less able to think and learn. Moreover, 
mercury exposure at high levels can harm the brain, heart, kidneys, 
lungs, and immune system of people of all ages.\6\
---------------------------------------------------------------------------

    \6\ For more information see http://www.epa.gov/mercury/about.htm.
---------------------------------------------------------------------------

    The majority of the fish consumed in the U.S. are ocean species. 
The methylmercury concentrations in ocean fish species are primarily 
influenced by the global mercury pool. However, the methylmercury found 
in local fish can be due, at least partly, to mercury emissions from 
local sources.
    Overall, this regulation will reduce mercury emissions from the 
gold ore processing and production source category by about 1,650 
pounds per year from current levels and, therefore, contribute to 
reductions in mercury exposures and health effects.

VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    This action is a ``significant regulatory action'' under the terms 
of Executive Order 12866 (58 FR 51735, October 4, 1993) because it may 
raise novel legal or policy issues. Accordingly, EPA submitted this 
action to the Office of Management and Budget (OMB) for review under 
Executive Order 12866, and any changes made in response to OMB 
recommendations have been

[[Page 22487]]

documented in the docket for this action.

B. Paperwork Reduction Act

    The information collection requirements in this proposed rule have 
been submitted for approval to OMB under the Paperwork Reduction Act, 
44 U.S.C. 3501 et seq. The Information Collection Request (ICR) 
document prepared by EPA has been assigned EPA ICR No. 2383.01.
    The recordkeeping and reporting requirements in this proposed rule 
are based, in large part, on the information collection requirements in 
EPA's NESHAP General Provisions (40 CFR part 63, subpart A). The 
recordkeeping and reporting requirements in the General Provisions are 
specifically authorized by section 114 of the CAA (42 U.S.C. 7414). All 
information other than emissions data submitted to EPA pursuant to the 
information collection requirements for which a claim of 
confidentiality is made is safeguarded according to CAA section 114(c) 
and EPA's implementing regulations at 40 CFR part 2, subpart B.
    This proposed NESHAP would require applicable one-time 
notifications according to the NESHAP General Provisions. In addition, 
owners or operators must submit annual notifications of compliance 
status and report any deviations in each semiannual reporting period. 
Records of all performance tests, measurements of feed input rates, 
monitoring data, and corrective actions would be required.
    The average annual burden for this information collection averaged 
over the first 3 years of this ICR is estimated to total 4,225 labor 
hours per year at a cost of approximately $213,726 per year for the 21 
facilities that would be subject to this proposed rule, or 
approximately 201 hours per year per facility. Capital costs are 
estimated as $1.3 million, operation and maintenance costs are 
estimated as $65,000 per year, and total annualized cost (including 
capital recovery) is estimated as $256,000 per year for this proposed 
rule's information collection requirements. No costs or burden hours 
are estimated for new sources because none is projected for the next 3 
years. Burden is defined at 5 CFR 1320.3(b).
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless the collection 
displays a currently valid OMB control number. The OMB control numbers 
for EPA's regulations in 40 CFR part 63 are listed in 40 CFR part 9.
    To comment on the Agency's need for this information, the accuracy 
of the provided burden estimates, and any suggested methods for 
minimizing respondent burden, EPA has established a public docket for 
this rule, which includes this ICR, under Docket ID number EPA-HQ-OAR-
2010-0239.
    Submit any comments related to the ICR to EPA and OMB. See 
ADDRESSES section at the beginning of this notice for where to submit 
comments to EPA. Send comments to OMB at the Office of Information and 
Regulatory Affairs, Office of Management and Budget, 725 17th Street, 
NW., Washington, DC 20503, Attention: Desk Office for EPA. Since OMB is 
required to make a decision concerning the ICR between 30 and 60 days 
after April 28, 2010, a comment to OMB is best assured of having its 
full effect if OMB receives it by May 28, 2010. The final rule will 
respond to any OMB or public comments on the information collection 
requirements contained in this proposal.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act generally requires an agency to 
prepare a regulatory flexibility analysis of any rule subject to notice 
and comment rulemaking requirements under the Administrative Procedure 
Act or any other statute unless the agency certifies that this rule 
would not have a significant economic impact on a substantial number of 
small entities. Small entities include small businesses, small not-for-
profit enterprises, and small governmental jurisdictions.
    For the purposes of assessing the impacts of this proposed NESHAP 
on small entities, a small entity is defined as: (1) A small business 
whose parent company meets the Small Business Administration size 
standards for small businesses found at 13 CFR 121.201 (less than 500 
employees for gold mine ore processing and production facilities--NAICS 
212221); (2) a small governmental jurisdiction that is a government of 
a city, county, town, school district, or special district with a 
population of less than 50,000; and (3) a small organization that is 
any not-for-profit enterprise that is independently owned and operated 
and is not dominant in its field.
    After considering the economic impacts of this proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. This 
proposed rule is estimated to impact about 21 gold mine ore processing 
and production facilities, none of which are owned by small entities. 
Thus, there are no impacts to small entities from this proposed rule. 
Although this proposed rule will contain requirements for new sources, 
EPA expects few, if any, new sources to be constructed in the next 
several years. Therefore, EPA did not estimate the impacts for new 
affected sources for this proposed rule.
    Although this proposed rule will not have a significant economic 
impact on a substantial number of small entities, EPA nonetheless has 
tried to reduce the impact of this proposed rule on small and large 
entities. These standards establish emission limits that reflect 
practices and controls that are used throughout the industry and in 
many cases are already required by State operating permits. These 
standards also require only the essential monitoring, recordkeeping, 
and reporting needed to verify compliance. These proposed standards 
were developed based on information obtained from industry 
representatives in our surveys, consultation with business 
representatives and their trade association and other stakeholders. We 
continue to be interested in the potential impacts of this proposed 
rule on small entities and welcome comments on issues related to such 
impacts.

D. Unfunded Mandates Reform Act

    This proposed rule does not contain a Federal mandate that may 
result in expenditures of $100 million or more for State, local, and 
Tribal governments, in the aggregate, or to the private sector in any 
one year. This proposed rule is not expected to impact State, local, or 
Tribal governments. The nationwide annualized cost of this proposed 
rule for affected industrial sources is $3.8 million/yr. Thus, this 
proposed rule is not subject to the requirements of sections 202 and 
205 of the Unfunded Mandates Reform Act (UMRA).
    This proposed rule is also not subject to the requirements of 
section 203 of UMRA because it contains no regulatory requirements that 
might significantly or uniquely affect small governments. This proposed 
rule will not apply to such governments and will not impose any 
obligations upon them.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government, as 
specified in Executive Order 13132. This proposed rule does not impose 
any requirements on State and local governments. Thus,

[[Page 22488]]

Executive Order 13132 does not apply to this action.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comment on this proposed action 
from State and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have Tribal implications, as specified in 
Executive Order 13175 (65 FR 67249, November 9, 2000). This proposed 
rule imposes no requirements on Tribal governments; thus, Executive 
Order 13175 does not apply to this action. EPA specifically solicits 
additional comment on this proposed action from Tribal officials.

G. Executive Order 13045: Protection of Children From Environmental 
Health and Safety Risks

    EPA interprets Executive Order 13045 (62 FR 19885, April 22, 1997) 
as applying only to those regulatory actions that are based on health 
or safety risks, such that the analysis required under section 5-501 of 
the Executive Order has the potential to influence the regulation. This 
action is not subject to Executive Order 13045 because it is based 
solely on technology performance.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy action'' as defined in 
Executive Order 13211 (66 FR 28355, May 22, 2001) because it is not 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy. We have concluded that this proposed 
rule will not likely have any significant adverse energy effects 
because energy consumption would increase by only 2,100 megawatt-hours 
per year.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113 (15 U.S.C. 272 note), 
directs EPA to use voluntary consensus standards (VCS) in its 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. VCS are technical standards 
(e.g., materials specifications, test methods, sampling procedures, 
business practices) that are developed or adopted by voluntary 
consensus standards bodies. NTTAA directs EPA to provide Congress, 
through OMB, explanations when the Agency decides not to use available 
and applicable VCS.
    This proposed rulemaking involves technical standards. EPA proposes 
to use ASME PTC 19.10-1981, ``Flue and Exhaust Gas Analyses,'' for its 
manual methods of measuring the oxygen or carbon dioxide content of the 
exhaust gas. These parts of ASME PTC 19.10-1981 are acceptable 
alternatives to EPA Method 3B. This standard is available from the 
American Society of Mechanical Engineers (ASME), Three Park Avenue, New 
York, NY 10016-5990.
    Another VCS, ASTM D6784-02, ``Standard Test Method for Elemental, 
Oxidized, Particle-Bound and Total Mercury in Flue Gas Generated From 
Coal-Fired Stationary Sources (Ontario Hydro Method)'' is an acceptable 
alternative to EPA Method 29. This performance test method is available 
from ASTM International. See http://www.astm.org/.
    EPA has also decided to use EPA Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 
2G, 3, 3A, 3B, 4, 29, 30A, 30B, Method 7471A, ``Mercury in Solid or 
Semisolid Waste (Manual Cold-Vapor Technique),'' and ASTM D6784-02, 
``Standard Test Method for Elemental, Oxidized, Particle-Bound and 
Total Mercury in Flue Gas Generated From Coal-Fired Stationary 
Sources,'' (incorporated by reference--see 63.14). Although the Agency 
has identified 14 VCS as being potentially applicable to these methods 
cited in this rule, we have decided not to use these standards in this 
proposed rulemaking. The use of these VCS would have been impractical 
because they do not meet the objectives of the standards cited in this 
rule. The search and review results are in the docket for this proposed 
rule.
    EPA welcomes comments on this aspect of this proposed rulemaking 
and, specifically, invites the public to identify potentially 
applicable voluntary consensus standards and to explain why such 
standards should be used in this regulation.
    Under section 63.7(f) and section 63.8(f) of Subpart A of the 
General Provisions, a source may apply to EPA for permission to use 
alternative test methods or alternative monitoring requirements in 
place of any required testing methods, performance specifications, or 
procedures in the proposed rule.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994) establishes 
Federal executive policy on environmental justice. Its main provision 
directs Federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    EPA has determined that this proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations because it will increase 
the level of environmental protection for all affected populations 
without having any disproportionately high and adverse human health or 
environmental effects on any population, including any minority or low-
income population. This proposed rule is expected to reduce mercury 
emissions from gold mine ore processing and production facilities and 
thus decrease the amount of such emissions to which all affected 
populations are exposed.

List of Subjects in 40 CFR Parts 9 and 63

    Environmental protection, Air pollution control, Hazardous 
substances, Incorporations by reference, Reporting and recordkeeping 
requirements.

    Dated: April 15, 2010.
Lisa P. Jackson,
Administrator.
    For the reasons stated in the preamble, title 40, chapter I, of the 
Code of Federal Regulations is proposed to be amended as follows:

PART 9--[AMENDED]

    1. The authority citation for part 9 continues to read as follows:

    Authority: 7 U.S.C. 135, et seq., 136-136y; 15 U.S.C. 2001, 
2003, 2005, 2006, 2601-2671; 21 U.S.C. 331j, 346a, 348; 31 U.S.C. 
9701; 33 U.S.C. 1251, et seq., 1311, 1313d, 1314, 1318, 1321, 1326, 
1330, 1342, 1344, 1345(d) and (e), 1361; E.O. 11735, 38 FR 21243, 3 
CFR, 1971-1975 Comp. p. 973; 42 U.S.C. 241, 242b, 243, 246, 300f, 
300g, 300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-1, 300j-
2, 300j-3, 300j-4, 300j-9, 1857, et seq., 6901-6992k, 7401-7671q, 
7542, 9601-9657, 11023, 11048.

[[Page 22489]]

Subpart A--[Amended]

* * * * *
    2. The table in Sec.  9.1 is amended by adding an entry in 
numerical order for ``63.11647-63.11648'' under the heading ``National 
Emission Standards for Hazardous Air Pollutants for Source Categories'' 
to read as follows:


Sec.  9.1  OMB Approvals under the Paperwork Reduction Act.

* * * * *

------------------------------------------------------------------------
             40 CFR citation                      OMB control No.
------------------------------------------------------------------------
 
                              * * * * * * *
------------------------------------------------------------------------
   National Emission Standards for Hazardous Air Pollutants for Source
                             Categories \3\
------------------------------------------------------------------------
 
                              * * * * * * *
------------------------------------------------------------------------
63.11647-63.11648.......................  2060-NEW
------------------------------------------------------------------------
 
                              * * * * * * *
------------------------------------------------------------------------
* * * * * * *
\3\ The ICRs referenced in this section of the table encompass the
  applicable general provisions contained in 40 CFR part 63, subpart A,
  which are not independent information collection requirements.

* * * * *

PART 63--[AMENDED]

    3. The authority citation for part 63 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart A--[Amended]

    4. Section 63.14 is amended by revising paragraphs (b)(35) and 
(i)(1) and by adding paragraph (k)(1)(v) to read as follows:


Sec.  63.14  Incorporations by reference.

* * * * *
    (b) * * *
    (35) ASTM D6784-02, Standard Test Method for Elemental, Oxidized, 
Particle-Bound and Total Mercury in Flue Gas Generated from Coal-Fired 
Stationary Sources (Ontario Hydro Method), IBR approved for Sec.  
63.11646(a)(1)(v) and table 5 to subpart DDDDD of this part.
* * * * *
    (i) * * *
    (1) ANSI/ASME PTC 19.10-1981, ``Flue and Exhaust Gas Analyses [Part 
10, Instruments and Apparatus],'' IBR approved for Sec. Sec.  
63.309(k)(1)(iii), 63.865(b), 63.3166(a)(3), 63.3360(e)(1)(iii), 
63.3545(a)(3), 63.3555(a)(3), 63.4166(a)(3), 63.4362(a)(3), 
63.4766(a)(3), 63.4965(a)(3), 63.5160(d)(1)(iii), 63.9307(c)(2), 
63.9323(a)(3), 63.11148(e)(3)(iii), 63.11155(e)(3), 63.11162(f)(3)(iii) 
and (f)(4), 63.11163(g)(1)(iii) and (g)(2), 63.11410(j)(1)(iii), 
63.11551(a)(2)(i)(C), 63.11646(a)(1)(iii), table 5 to subpart DDDDD of 
this part, and table 1 to subpart ZZZZZ of this part.
* * * * *
    (k) * * *
    (1) * * *
    (v) Method 7471A, ``Mercury in Solid or Semisolid Waste (Manual 
Cold-Vapor Technique),'' IBR approved for Sec.  63.11647(f)(2).
* * * * *
    5. Part 63 is amended by adding subpart EEEEEEE to read as follows:
Subpart EEEEEEE--National Emission Standards for Hazardous Air 
Pollutants: Gold Mine Ore Processing and Production Area Source 
Category

Applicability and Compliance Dates

Sec.
63.11640 Am I subject to this subpart?
63.11641 What are my compliance dates?

Standards and Compliance Requirements

63.11645 What are my mercury emission standards?
63.11646 What are my compliance requirements?
63.11647 What are my monitoring requirements?
63.11648 What are my notification, reporting, and recordkeeping 
requirements?

Other Requirements and Information

63.11650 What General Provisions apply to this subpart?
63.11651 What definitions apply to this subpart?
63.11652 Who implements and enforces this subpart?
63.11653 [Reserved]

Tables to Subpart EEEEEEE of Part 63

Table 1 to Subpart EEEEEEE of Part 63--Applicability of General 
Provisions to Subpart EEEEEEE

Subpart EEEEEEE--National Emission Standards for Hazardous Air 
Pollutants: Gold Mine Ore Processing and Production Area Source 
Category

Applicability and Compliance Dates


Sec.  63.11640  Am I subject to this subpart?

    (a) You are subject to this subpart if you own or operate a gold 
mine ore processing and production facility as defined in Sec.  
63.11651, that is an area source.
    (b) This subpart applies to each new or existing affected source. 
The affected sources are each collection of ``ore pretreatment 
processes'' at a gold mine ore processing and production facility, each 
collection of ``carbon processes'' at a gold mine ore processing and 
production facility, and each collection of ``non-carbon concentrate 
processes'' at a gold mine ore processing and production facility, as 
defined in Sec.  63.11651.
    (1) An affected source is existing if you commenced construction or 
reconstruction of the affected source on or before April 28, 2010.
    (2) An affected source is new if you commenced construction or 
reconstruction of the affected source after April 28, 2010.
    (c) This subpart does not apply to research and development 
facilities, as defined in section 112(c)(7) of the Clean Air Act (CAA).
    (d) If you own or operate a source subject to this subpart, you 
must have or you must obtain a permit under 40 CFR part 70 or 40 CFR 
part 71.


Sec.  63.11641  What are my compliance dates?

    (a) If you own or operate an existing affected source, you must 
comply with the applicable provisions of this subpart

[[Page 22490]]

no later than 2 years after the date of publication of the final rule 
in the Federal Register.
    (b) If you start up a new affected source on or before the date of 
publication of the final rule in the Federal Register, you must comply 
with the provisions of this subpart no later than the date of 
publication of the final rule in the Federal Register.
    (c) If you start up a new affected source after the date of 
publication of the final rule in the Federal Register, you must comply 
with the provisions of this subpart upon startup of your affected 
source.

Standards and Compliance Requirements


Sec.  63.11645  What are my mercury emission standards?

    (a) For existing ore pretreatment processes, you must emit no more 
than 149 pounds of mercury per million tons of ore processed.
    (b) For existing carbon processes, you must emit no more than 2.6 
pounds of mercury per ton of concentrate processed.
    (c) For existing non-carbon concentrate processes, you must emit no 
more than 0.25 pounds of mercury per ton of concentrate processed.
    (d) For new ore pretreatment processes, you must emit no more than 
149 pounds of mercury per million tons of ore processed.
    (e) For new carbon processes, you must either:
    (1) Emit no more than 0.14 pounds of mercury per ton of concentrate 
processed, or
    (2) Achieve a 97-percent reduction in mercury emissions as measured 
before and after the mercury emission control devices.
    (f) For new non-carbon concentrate processes, you must emit no more 
than 0.2 pounds of mercury per ton of concentrate processed.
    (g) The standards set forth in this section apply at all times.


Sec.  63.11646  What are my compliance requirements?

    (a) Except as provided in paragraph (b) of this section, you must 
conduct a mercury compliance emission test within 180 days of the 
compliance date for all process units at new and existing affected 
sources according to the requirements in paragraphs (a)(1) through (13) 
of this section. This compliance testing must be repeated annually 
thereafter (i.e., once every four successive calendar quarters).
    (1) You must determine the concentration of mercury and the 
volumetric flow rate of the stack gas according to the following test 
methods and procedures:
    (i) Method 1 or 1A (40 CFR part 60, appendix A-1) to select 
sampling port locations and the number of traverse points in each stack 
or duct. Sampling sites must be located at the outlet of the control 
device (or at the outlet of the emissions source if no control device 
is present) and prior to any releases to the atmosphere.
    (ii) Method 2, 2A, 2C, 2D, 2F (40 CFR part 60, appendix A-1), or 
Method 2G (40 CFR part 60, appendix A-2) to determine the volumetric 
flow rate of the stack gas.
    (iii) Method 3, 3A, or 3B (40 CFR part 60, appendix A-2) to 
determine the dry molecular weight of the stack gas. You may use ANSI/
ASME PTC 19.10-1981, ``Flue and Exhaust Gas Analyses'' (incorporated by 
reference--see Sec.  63.14) as an alternative to EPA Method 3B.
    (iv) Method 4 (40 CFR part 60, appendix A-3) to determine the 
moisture content of the stack gas.
    (v) Method 29 (40 CFR part 60, appendix A-8), ASTM D6784-02; 
``Standard Test Method for Elemental, Oxidized, Particle-Bound and 
Total Mercury in Flue Gas Generated from Coal-Fired Stationary Sources 
(Ontario Hydro Method)'' (incorporated by reference--see Sec.  63.14); 
Method 30A (40 CFR part 60, appendix A-8); or Method 30B (40 CFR part 
60, appendix A-8) to determine the concentration of mercury. If you use 
Method 29, the acetone rinse procedures in Section 8.2.6 of the method 
must be followed and are not optional (i.e., quantitative removal of 
particulate matter and any condensate from the sampling apparatus 
(probe nozzle, fitting, holder) and front half of the filter holder 
must be performed using acetone).
    (vi) The absence of cyclonic flow must be determined prior to or 
during the test. For retorts and other narrow stacks where sampling is 
done at a single point with a standard pitot tube, a ``null'' check 
must be performed prior to sampling.
    (2) A minimum of three test runs must be conducted for each 
performance test of each process unit. Each test run must be conducted 
for at least two hours and collect a minimum sample volume of 1.7 dry 
standard cubic meters (60 dry standard cubic feet).
    (3) Tests must be conducted under operating conditions (including 
process or production throughputs) that are based on representative 
performance. Record and report the process throughput for each test 
run.
    (4) Calculate the mercury emission rate for each process unit using 
Equation (1) of this section:
[GRAPHIC] [TIFF OMITTED] TP28AP10.022

Where:

E = mercury emissions in lb/hr;
Cs = concentration of mercury in the stack gas, in milligrams per 
dry standard cubic meter (mg/dscm);
Qs = volumetric flow rate of the stack gas, in dry standard cubic 
feet per hour; and
K = conversion factor from mg/dscm to pounds per dry standard cubic 
foot, 6.23 x 10- 8.

    (5) Monitor and record the number of hours each process unit 
operates during each month.
    (6) For the initial compliance determination for both new and 
existing sources, determine the total mercury emissions for the 6-month 
period following the compliance date by multiplying the emission rate 
in lb/hr for each process unit by the number of hours each process unit 
operated during the 6-month period. After the initial 6 months 
following the compliance date, determine the annual mercury mass 
emissions in accordance with the procedures in paragraph (a)(7) of this 
section. Existing sources may use a previous emission test for their 
initial compliance determination in lieu of conducting a new test if 
the test was conducted within one year of the compliance date using the 
methods specified in paragraphs (a)(1) through (4) of this section, and 
the tests were representative of current operating processes and 
conditions.
    (7) For compliance determinations following the initial compliance 
test for new and existing sources, determine the total mercury mass 
emissions for each process unit for the 12-month period preceding the 
performance test by multiplying the emission rate in lb/hr for each 
process unit by the number of hours each process unit operated during 
the 12-month period preceding the completion of the performance tests.
    (8) You must install, calibrate, maintain and operate an 
appropriate weight measurement device or densitometers and volumetric 
flow

[[Page 22491]]

meters to measure ore throughput for each roasting operation and 
autoclave and calculate hourly, daily and monthly totals in tons of as 
fed ore.
    (i) Measure the weight or the density and volumetric flow rate of 
the oxidized ore slurry as it exits the roaster oxidation circuit and 
before the carbon-in-leach tanks.
    (ii) Measure the weight or the density and volumetric flow rate of 
the ore slurry as it is fed to the autoclave(s).
    (9) Measure the weight of concentrate processed (by electrowinning, 
Merrill Crowe process, gravity feed, or other methods) using weigh 
scales for each batch prior to retorting. The concentrate must be 
weighed in the same State and condition as it is when fed to the 
retort. For facilities without retorts, the concentrate must be weighed 
prior to being fed to the melt furnace before drying in any ovens. For 
facilities that ship concentrate offsite, measure the weight of 
concentrate as shipped offsite. You must keep accurate records of the 
weights of each batch of concentrate processed and calculate and record 
the total weight of concentrate processed each month.
    (10) You must maintain the systems for measuring density, 
volumetric flow rate, and weight within 5 percent accuracy. 
You must describe the specific equipment used to make measurements at 
your facility and how that equipment is periodically calibrated. You 
must also explain, document, and maintain written procedures for 
determining the accuracy of the measurements and make these written 
procedures available to your permitting authority upon request. You 
must determine, record, and maintain a record of the accuracy of the 
measuring systems before the beginning of your initial compliance test 
and during each subsequent quarter of affected source operation.
    (11) Record the weight in tons of ore for ore pretreatment 
processes and concentrate for carbon processes and for non-carbon 
concentrate processes on a daily and monthly basis.
    (12) Calculate the emissions from each new and existing affected 
source for the 6-month period following the compliance date in pounds 
of mercury per ton of process input using the procedures in paragraphs 
(a)(12)(i) through (iii) of this section to determine initial 
compliance with the emission standards in Sec.  63.11645. After the 
initial 6-month period, determine annual compliance using the 
procedures in paragraph (a)(13) of this section for existing sources.
    (i) For ore pretreatment processes, divide the sum of mercury mass 
emissions from all roasting operations and autoclaves during the 
initial 6-month period following the compliance date by the sum of the 
total amount of gold mine ore processed in these process units during 
the 6-month period following the compliance date.
    (ii) For carbon processes, divide the sum of mercury mass emissions 
from all carbon kilns, preg tanks, electrowinning, retorts, and melt 
furnaces during the initial 6-month period following the compliance 
date by the total amount of concentrate processed in these process 
units during the initial 6-month period following the compliance date.
    (iii) For non-carbon concentrate processes, divide the sum of 
mercury mass emissions from retorts and melt furnaces during the 
initial 6-month period following the compliance date by the total 
amount of concentrate processed in these process units during the 6-
month period following the compliance date.
    (13) After the initial compliance test, calculate the emissions 
from each new and existing affected source for each 12-month period 
preceding each subsequent compliance test in pounds of mercury per ton 
of process input using the procedures in paragraphs (a)(13)(i) through 
(iii) of this section to determine compliance with the emission 
standards in Sec.  63.11645.
    (i) For ore pretreatment processes, divide the sum of mercury mass 
emissions from all roasting operations and autoclaves in the 12-month 
period preceding a compliance test by the sum of the total amount of 
gold mine ore processed in that 12-month period.
    (ii) For carbon processes, divide the sum of mercury mass emissions 
from all carbon kilns, preg tanks, electrowinning, retorts, and melt 
furnaces in the 12-month period preceding a compliance test by the 
total amount of concentrate processed in these process units in that 
12-month period.
    (iii) For non-carbon concentrate processes, divide the sum of 
mercury mass emissions from retorts and melt furnaces in the 12-month 
period preceding a compliance test by the total amount of concentrate 
processed in these process units in that 12-month period.
    (b) If you have a new carbon processes affected source and elect to 
comply with the percent reduction standard in Sec.  63.11645(e)(2), you 
must perform annual tests of the inlet and outlet to each control 
device used in the new affected source and calculate emissions at the 
inlet and outlet using the methods and procedures in paragraphs (a)(1) 
through (7) of this section. The sampling and analysis of inlet 
emissions for retorts must be performed following the mercury condenser 
and before the carbon adsorber. Calculate the percent reduction in 
mercury emissions based on the difference in emission rates at the 
inlet and outlet to each control device. Perform a compliance 
determination for the initial 6-month period following the compliance 
date using the procedures in paragraph (a)(6) of this section. Perform 
compliance determinations annually following the initial 6-month period 
using the procedures in paragraph (a)(7) of this section.
    (c) At all times, you must operate and maintain any affected 
source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions.


Sec.  63.11647  What are my monitoring requirements?

    (a) Except as provided in paragraph (a)(4) of this section, you 
must monitor each roaster for mercury emissions using one of the 
procedures in paragraphs (a)(1) or (2) of this section and establish 
operating limits for mercury concentration as described in paragraph 
(a)(3) of this section.
    (1) Perform sampling and analysis of the roaster's exhaust for 
mercury concentration using EPA Performance Specification 12B each week 
and maintain the daily average concentration below the operating limit 
established in paragraph (a)(3) of this section.
    (i) To determine the appropriate sampling duration, you must review 
the available data from previous stack tests to determine the upper 
99th percentile of the range of mercury concentrations in the exit 
stack gas. Based on this upper end of expected concentrations, select 
an appropriate sampling duration that is likely to provide a valid 
sample and not result in breakthrough of the sampling tubes. If 
breakthrough of the sampling tubes occurs, you must re-sample within 30 
days using a shorter sampling duration.
    (ii) If you measure a daily average concentration above the 
operating limit, you must take corrective action and correct the 
problem within 48 hours of the exceedance or stop the feed of ore to 
the roaster, and report the exceedance as a deviation.
    (2) Install, operate, calibrate, and maintain a continuous 
emissions monitoring system (CEMS) to continuously measure the mercury 
concentration in the final exhaust stream from each roaster according 
to

[[Page 22492]]

the requirements of Performance Specification 12A (40 CFR part 60, 
appendix B) except that calibration standards traceable to the National 
Institute of Standards and Technology are not required. You must 
perform a data accuracy assessment of the CEMS according to section 5 
of Appendix F in part 60 and follow the monitoring requirements in 
Sec.  63.8.
    (i) You must continuously monitor the daily average mercury 
concentration from the roaster and maintain the daily average 
concentration below the operating limit established in paragraph (a)(3) 
of this section. If you measure a daily average concentration above the 
operating limit, you must take corrective action and correct the 
problem within 48 hours of the exceedance or stop the feed of ore to 
the roaster, and report the exceedance as a deviation.
    (ii) You must submit a monitoring plan that includes quality 
assurance and quality control (QA/QC) procedures sufficient to 
demonstrate the accuracy of the CEMS to your permitting authority for 
approval 180 days prior to your initial compliance test. At a minimum, 
the QA/QC procedures must include daily calibrations and an annual 
accuracy test for the CEMS.
    (3) Use Equation (2) of this section to establish an upper 
operating limit for mercury concentration as determined by using the 
procedures in paragraphs (a)(1) or (2) of this section concurrently 
while you are also doing your annual compliance performance stack test 
according to the procedures in Sec.  63.11646(a).
[GRAPHIC] [TIFF OMITTED] TP28AP10.023

Where:

OLR = mercury concentration operating limit for the roaster (in 
micrograms per cubic meter);
Ctest = average mercury concentration measured by the 
monitoring procedures (PS 12A or PS 12B) during the annual 
performance stack test (in micrograms per cubic meter);
149 = emission limit for ore pretreatment processes (in lb/million 
tons of ore);
CT = compliance test results for ore pretreatment processes (in lb/
million tons of ore).

    (4) For roasters that utilize calomel-based mercury control systems 
for emissions controls, you are not required to perform the monitoring 
for mercury emissions in paragraphs (a)(1) or (2) of this section if 
you demonstrate to the satisfaction of your permitting authority that 
mercury emissions from the roaster are less than 10 pounds of mercury 
per million tons of ore throughput. If you make this demonstration, you 
must conduct the parametric monitoring as described below in paragraphs 
(b) and (c) of this section.
    (i) The initial demonstration must include three or more 
consecutive independent stack tests for mercury at least one month 
apart on the roaster exhaust stacks. Subsequent demonstrations may be 
based upon the single stack test required in paragraph (a) of section 
Sec.  63.11646. The results of each of the tests must be less than 10 
pounds of mercury per million tons of ore. The testing must be 
performed according to the procedures in Sec.  63.11646(a)(1) through 
(4) to determine mercury emissions in pounds per hour.
    (ii) Divide the mercury emission rate in pounds per hour by the ore 
throughput rate during the test expressed in millions of tons per hour 
to determine the emissions in pounds per million tons of ore.
    (iii) You must continue to perform annual compliance tests of the 
roaster stack as required in Sec.  63.11646(a). In addition, if the 
mercury concentration in the ore processed in the roaster increases to 
a level higher than any mercury concentration measured in the previous 
12 months, you must perform a compliance test within 30 days of the 
first day that the ore with higher mercury levels is processed to 
determine whether the mercury emissions are still below 10 lbs per 
million tons of ore. If any subsequent compliance tests indicate that 
the roaster is emitting more than 10 pounds of mercury per million tons 
of ore input, then you must implement the monitoring required in 
paragraphs (a)(1) or (2) of this section within 30 days.
    (b) For facilities with roasters and a calomel-based mercury 
control system that choose to monitor for mercury emissions using the 
procedures in paragraph (a)(1) of this section or that qualify for and 
choose to follow the requirements in paragraph (a)(4) of this section, 
you must establish operating parameters for scrubber liquor flow, 
scrubber pressure drop and scrubber inlet gas temperature and monitor 
these parameters. Monitor the scrubber liquor flow, scrubber pressure 
drop and scrubber inlet gas temperature during each run of your initial 
compliance test. The minimum operating rate for scrubber liquor flow 
and pressure drop are the lowest values during any run of the initial 
compliance test, and your maximum scrubber inlet temperature limit is 
the highest measured during any run of the initial compliance test. 
Subsequently, you must monitor the scrubber liquor flow, scrubber 
pressure drop and scrubber inlet gas temperature hourly and maintain 
the scrubber liquor flow and scrubber pressure drop at or above the 
operating parameters established during the initial compliance test and 
maintain the inlet gas temperature below the operating parameters 
established during the initial compliance test.
    (c) For facilities with roasters and a calomel-based mercury 
control system that choose to monitor for mercury emissions using the 
procedures in paragraph (a)(1) of this section or that qualify for and 
follow the requirements in paragraph (a)(4) of this section, you must 
establish operating parameters for mercuric ion and chloride ion 
concentrations or for oxidation reduction potential and pH using the 
procedures in either paragraph (c)(1) or (2) of this section.
    (1) Establish the mercuric ion concentration and chloride ion 
concentration range for each calomel-based mercury control system. The 
mercuric ion concentration and chloride ion concentration for each 
calomel-based mercury control system must be based on the 
manufacturer's specifications. Alternatively, the mercuric ion 
concentration and chloride ion concentration range for each calomel-
based mercury control system may be approved by your permitting 
authority. Measure the mercuric ion concentration and chloride ion 
concentrations at least once during each run of your initial compliance 
test. The measurements must be within the established concentration 
range for mercuric ion concentration and chloride ion concentration. 
Subsequently, you must sample four times daily and maintain the 
mercuric ion concentration and chloride ion concentrations within their 
established range.
    (2) Establish the oxidation reduction potential and pH range for 
each calomel-based mercury control system. The oxidation reduction 
potential and pH range for each calomel-based mercury control system 
must be based on the manufacturer's specifications.

[[Page 22493]]

Alternatively, the oxidation reduction potential and pH range for each 
calomel-based mercury control system may be approved by your permitting 
authority. Install monitoring equipment to continuously monitor the 
oxidation reduction potential and pH of the calomel-based mercury 
control system scrubber liquor. Measure the oxidation reduction 
potential and pH of the scrubber liquor during each run of your initial 
compliance test. The measurements must be within the established range 
for oxidation reduction potential and pH. Subsequently, you must 
monitor the oxidation reduction potential and pH of the scrubber liquor 
continuously and maintain it within the established operating range.
    (d) If you have an exceedance of an operating limit or range in 
paragraphs (b) or (c) of this section, you must take corrective action 
and bring the system operations back into the specified operational 
range or limit within 45 minutes or commence shutdown of the roaster.
    (e) You may submit a request to your permitting authority for 
approval to change the operating limits established under paragraph 
(a)(3) of this section for the monitoring required in paragraph (a)(1) 
or (2) of this section. In the request, you must demonstrate that the 
proposed change to the operating limit detects changes in levels of 
mercury emission control. An approved change to the operating limit 
under this paragraph only applies until a new operating limit is 
established during the next annual compliance test.
    (f) You must monitor each process unit at each new and existing 
affected source that uses a carbon adsorber to control mercury 
emissions using the procedures in paragraphs (f)(1), (2), or (3) of 
this section.
    (1) Continuously sample and analyze the exhaust stream from the 
carbon adsorber for mercury using Method 30B (40 CFR part 60, appendix 
A-8) for one week that includes the period of the annual performance 
test.
    (i) Establish an upper operating limit for the process as 
determined using the mercury concentration measurements from the 
sorbent trap as calculated from Equation (3) of this section.
[GRAPHIC] [TIFF OMITTED] TP28AP10.024

Where:

OLC = mercury concentration operating limit for the process as 
measured using the sorbent trap, (micrograms per cubic meter);
Ctrap = average mercury concentration measured using the 
sorbent trap during the week that includes the performance test, 
(micrograms per cubic meter);
EL = emission limit for the affected sources (lb/ton of 
concentrate);
CT = compliance test results for the affected sources (lb/ton of 
concentrate).

    (ii) Sample and analyze the exhaust stream from the carbon adsorber 
for mercury at least monthly using Method 30B (40 CFR part 60, appendix 
A-8). When the mercury concentration reaches 50 percent of the 
operating limit, begin weekly sampling and analysis. When the mercury 
concentration reaches 90 percent of the operating limit, replace the 
carbon in the carbon adsorber within 30 days.
    (2) Conduct an initial sampling of the carbon in the carbon bed for 
mercury 90 days after the replacement of the carbon. A representative 
sample must be collected from the top of the bed and the exit of the 
bed and analyzed using EPA Method 7471A (incorporated by reference--see 
Sec.  63.14). The depth to which the sampler is inserted must be 
recorded. Calculate an average carbon loading from the two 
measurements. Sampling and analysis of the carbon bed for mercury must 
be performed quarterly thereafter. When the carbon loading reaches 50 
percent of the design capacity of the carbon, monthly sampling must be 
performed until 90 percent of the carbon loading capacity is reached. 
The carbon must be removed and replaced with fresh carbon no later than 
30 days after reaching 90 percent of capacity.
    (3) Calculate the change out rate for the carbon in the carbon 
adsorber based on the carbon lifetime as determined from at least 2 
years of data for the process unit from following the procedures in 
paragraphs (f)(1) or (2) of this section. You must submit supporting 
data and request approval from your permitting authority to 
periodically change out the carbon instead of monitoring. After 
approval from your permitting authority, change out the carbon in the 
carbon adsorber no less frequently than the established lifetime. If 
you change the process or inputs in such a manner that mercury 
emissions might increase (e.g., increase throughput), you must re-
establish the change out period based on two years of historical data 
as described in this paragraph.
    (g) You must monitor gas stream temperature at the inlet to the 
carbon adsorber for each autoclave, carbon kiln, melt furnace, and 
retort equipped with a carbon adsorber during the annual performance 
test required in Sec.  63.11646(a) and establish a maximum value for 
the inlet temperature. Establish the temperature operating limit based 
on either the highest reading during the test or at 10 [deg]F higher 
than the average temperature measured during the performance test. 
Continuously monitor the inlet temperature thereafter. If an hourly 
average inlet temperature exceeds the temperature operating limit, you 
must follow the requirements for outlet concentration measurement in 
paragraph (f)(1) of this section. If the concentration is below 90 
percent of the operating limit, you may set a new temperature operating 
limit 10 [deg]F above the previous operating limit. If the 
concentration is above 90 percent of the operating limit, you must take 
corrective action to reduce the temperature back below the temperature 
operating limit and again measure the outlet concentration according to 
paragraph (f)(1) of this section. If the concentration is still above 
90 percent of the operating limit, then you must change the carbon in 
the bed within 30 days.
    (h) For each wet scrubber at each new and existing affected source, 
you must monitor the water flow rate and pressure drop during the 
performance test required in Sec.  63.11646(a) and establish a minimum 
value as the operating limit based on either the lowest average value 
during any test run or as no lower than 10 percent of the average value 
measured during the test. You must continuously monitor the water flow 
rate and pressure drop and take corrective action within 24 hours if 
any daily average is less than the operating limit.
    (i) You may conduct additional compliance tests according to the 
procedures in Sec.  63.11646 and re-establish the operating limits 
required in paragraphs (a) through (c) and (f) through (h) of this 
section at any time.


Sec.  63.11648  What are my notification, reporting, and recordkeeping 
requirements?

    (a) You must submit the Initial Notification required by Sec.  
63.9(b)(2) no later than 120 calendar days after the date of 
publication of the final rule in the Federal Register or within 120 
days

[[Page 22494]]

after the source becomes subject to the standard. The Initial 
Notification must include the information specified in Sec.  
63.9(b)(2)(i) through (b)(2)(iv).
    (b) You must submit an initial Notification of Compliance Status as 
required by Sec.  63.9(h).
    (c) If a deviation occurs during a semiannual reporting period, you 
must submit a deviation report to your permitting authority according 
to the requirements in paragraphs (c)(1) and (2) of this section.
    (1) The first reporting period covers the period beginning on the 
compliance date specified in Sec.  63.11641 and ending on June 30 or 
December 31, whichever date comes first after your compliance date. 
Each subsequent reporting period covers the semiannual period from 
January 1 through June 30 or from July 1 through December 31. Your 
deviation report must be postmarked or delivered no later than July 31 
or January 31, whichever date comes first after the end of the 
semiannual reporting period.
    (2) A deviation report must include the information in paragraphs 
(c)(2)(i) through (iv) of this section.
    (i) Company name and address.
    (ii) Statement by a responsible official, with the official's name, 
title, and signature, certifying the truth, accuracy and completeness 
of the content of the report.
    (iii) Date of the report and beginning and ending dates of the 
reporting period.
    (iv) Identification of the affected source, the pollutant being 
monitored, applicable requirement, description of deviation, and 
corrective action taken.
    (d) If you had a malfunction during the reporting period, the 
compliance report must include the number, duration, and a brief 
description for each type of malfunction which occurred during the 
reporting period and which caused or may have caused any applicable 
emission limitation to be exceeded. The report must also include a 
description of actions taken by an owner or operator during a 
malfunction of an affected source to minimize emissions in accordance 
with Sec.  63.11646(c), including actions taken to correct a 
malfunction.
    (e) You must keep the records specified in paragraphs (e)(1) 
through (3) of this section.
    (1) As required in Sec.  63.10(b)(2)(xiv), you must keep a copy of 
each notification that you submitted to comply with this subpart and 
all documentation supporting any Initial Notification, Notification of 
Compliance Status, and semiannual compliance certifications that you 
submitted.
    (2) You must keep the records of all performance tests, monitoring 
data, and corrective actions required by Sec. Sec.  63.11646 and 
63.11647, and the information identified in paragraphs (c)(2)(i) 
through (vi) of this section for each corrective action required by 
Sec.  63.11647.
    (i) The date, place, and time of the monitoring event requiring 
corrective action;
    (ii) Technique or method used for monitoring;
    (iv) Operating conditions during the activity;
    (v) Results, including the date, time, and duration of the period 
from the time the monitoring indicated a problem (e.g., VE) to the time 
that monitoring indicated proper operation; and
    (vi) Maintenance or corrective action taken (if applicable).
    (3) You must keep records of operating hours for each process as 
required by Sec.  63.11646(a)(5) and records of the monthly quantity of 
ore and concentrate processed as required by Sec.  63.11646(a)(10).
    (f) Your records must be in a form suitable and readily available 
for expeditious review, according to Sec.  63.10(b)(1). As specified in 
Sec.  63.10(b)(1), you must keep each record for 5 years following the 
date of each recorded action. You must keep each record onsite for at 
least 2 years after the date of each recorded action according to Sec.  
63.10(b)(1). You may keep the records offsite for the remaining 3 
years.
    (g) After December 31, 2011, within 60 days after the date of 
completing each performance evaluation conducted to demonstrate 
compliance with this subpart, the owner or operator of the affected 
facility must submit the test data to EPA by entering the data 
electronically into EPA's WebFIRE data base through EPA's Central Data 
Exchange. The owner or operator of an affected facility shall enter the 
test data into EPA's data base using the Electronic Reporting Tool or 
other compatible electronic spreadsheet. Only performance evaluation 
data collected using methods compatible with ERT are subject to this 
requirement to be submitted electronically into EPA's WebFIRE database.

Other Requirements and Information


Sec.  63.11650  What General Provisions apply to this subpart?

    Table 1 to this subpart shows which parts of the General Provisions 
in Sec. Sec.  63.1 through 63.16 apply to you.


Sec.  63.11651  What definitions apply to this subpart?

    Terms used in this subpart are defined in the Clean Air Act, in 
Sec.  63.2, and in this section as follows:
    Autoclave means a pressure oxidation vessel that is used to treat 
gold ores (primarily sulfide refractory ore) and involves pumping a 
slurry of milled ore into the vessel which is highly pressurized with 
oxygen and heated to temperatures of approximately 350 to 430[deg]F.
    Calomel-based mercury control system means a mercury emissions 
control system that uses scrubbers to remove mercury from the gas 
stream of a roaster or combination of roasters by complexing the 
mercury from the gas stream with mercuric chloride to form mercurous 
chloride (calomel). Sometimes these scrubbers are also referred to as 
``mercury scrubbers.''
    Carbon kiln means a kiln or furnace where carbon is regenerated by 
heating, usually in the presence of steam, after the gold has been 
stripped from the carbon.
    Carbon processes means the affected source that includes carbon 
kilns, preg tanks, electrowinning cells, mercury retorts, and melt 
furnaces at gold mine ore processing and production facilities that use 
activated carbon to recover (adsorb) gold from the pregnant cyanide 
solution.
    Concentrate means the sludge-like material that is loaded with gold 
along with various other metals (such as silver, copper, and mercury) 
and various other substances, that is produced by electrowinning, the 
Merrill-Crowe process, flotation and gravity separation processes. 
Concentrate is measured as the input to retorts, or for facilities 
without retorts, as the input to melt furnaces before any drying takes 
place. For facilities without retorts or melt furnaces, concentrate is 
measured as the quantity shipped.
    Deviation means any instance where an affected source subject to 
this subpart, or an owner or operator of such a source:
    (1) Fails to meet any requirement or obligation established by this 
subpart, including but not limited to any emissions limitation or work 
practice standard;
    (2) Fails to meet any term or condition that is adopted to 
implement an applicable requirement in this subpart and that is 
included in the operating permit for any affected source required to 
obtain such a permit; or
    (3) Exceeds any operating limit established under this subpart.
    Electrowinning means a process that uses induced voltage on anode 
and

[[Page 22495]]

cathode plates to remove metals from the continuous flow of solution, 
where the gold in solution is plated onto the cathode. Steel wool is 
typically used as the plating surface.
    Electrowinning Cells means a tank in which the electrowinning takes 
place.
    Gold mine ore processing and production facility means any facility 
engaged in the processing of gold mine ore that uses any of the 
following processes: roasting operations, autoclaves, carbon kilns, 
preg tanks, electrowinning, retorts, or melt furnaces. A facility that 
produces primarily copper (where copper is 95 percent or more of the 
total metal production) that may also recover some gold as a byproduct 
is not a gold mine ore processing and production facility.
    Melt furnace means a furnace (typically a crucible furnace) that is 
used for smelting the gold-bearing material recovered from retorting, 
or the gold-bearing material from electrowinning, the Merrill-Crowe 
process or other processes for facilities without retorts.
    Merrill-Crowe process means a precipitation technique using zinc 
oxide for removing gold from a cyanide solution. Zinc dust is added to 
the solution, and gold is precipitated to produce a concentrate.
    Non-carbon concentrate processes means the affected source that 
includes retorts and melt furnaces at gold mine ore processing and 
production facilities that use the Merrill-Crowe process or other 
processes and do not use carbon to recover (adsorb) gold from the 
pregnant cyanide solution.
    Ore dry grinding means a process in which the gold ore is ground 
and heated (dried) prior to additional preheating or prior to entering 
the roaster.
    Ore preheating means a process in which ground gold ore is 
preheated prior to entering the roaster.
    Ore pretreatment processes means the affected source that includes 
roasting operations and autoclaves that are used to pre-treat gold mine 
ore at gold mine ore processing and production facilities prior to the 
cyanide leaching process.
    Pregnant solution tank (or preg tank) means a storage tank for 
pregnant solution, which is the cyanide solution that contains gold-
cyanide complexes that is generated from leaching gold ore with cyanide 
solution.
    Pregnant cyanide solution means the cyanide solution that contains 
gold-cyanide complexes that are generated from leaching gold ore with a 
dilute cyanide solution.
    Quenching means a process in which the hot calcined ore is cooled 
and quenched with water after it leaves the roaster.
    Retort means a vessel that is operated under a partial vacuum at 
approximately 1,100 to 1,300 [deg]F to remove mercury and moisture from 
the gold bearing sludge material that is recovered from electrowinning, 
the Merrill-Crowe process or other processes. Retorts are usually 
equipped with condensers that recover liquid mercury during the 
processing.
    Roasting operation means a process that uses an industrial furnace 
in which milled ore is combusted across a fluidized bed to oxidize and 
remove organic carbon and sulfide mineral grains in refractory gold 
ore. The emissions points of the roasting operation subject to this 
subpart include ore dry grinding, ore preheating, the roaster stack, 
and quenching.


Sec.  63.11652  Who implements and enforces this subpart?

    (a) This subpart can be implemented and enforced by the U.S. EPA or 
a delegated authority, such as your State, local, or Tribal agency. If 
the U.S. EPA Administrator has delegated authority to your State, 
local, or Tribal agency, then that agency has the authority to 
implement and enforce this subpart. You should contact your U.S. EPA 
Regional Office to find out if this subpart is delegated to your State, 
local, or Tribal agency.
    (b) In delegating implementation and enforcement authority of this 
subpart to a State, local, or Tribal agency under 40 CFR part 63, 
subpart E, the authorities contained in paragraph (c) of this section 
are retained by the Administrator of the U.S. EPA and are not 
transferred to the State, local, or Tribal agency.
    (c) The authorities that will not be delegated to State, local, or 
Tribal agencies are listed in paragraphs (c)(1) through (4) of this 
section.
    (1) Approval of alternatives to the applicability requirements in 
Sec.  63.11640, the compliance date requirements in Sec.  63.11641, and 
the applicable standards in Sec.  63.11645.
    (2) Approval of an alternative nonopacity emissions standard under 
Sec.  63.6(g).
    (3) Approval of a major change to a test method under Sec.  
63.7(e)(2)(ii) and (f). A ``major change to test method'' is defined in 
Sec.  63.90(a).
    (4) Approval of a major change to monitoring under Sec.  63.8(f). A 
``major change to monitoring'' is defined in Sec.  63.90(a).
    (5) Approval of a waiver of recordkeeping or reporting requirements 
under Sec.  63.10(f), or another major change to recordkeeping/
reporting. A ``major change to recordkeeping/reporting'' is defined in 
Sec.  63.90(a).


Sec.  63.11653  [Reserved]

Tables to Subpart EEEEEEE of Part 63

          Table 1 to Subpart EEEEEEE of Part 63--Applicability of General Provisions to Subpart EEEEEE
 [As stated in Sec.   63.11650, you must comply with the applicable General Provisions requirements according to
                                              the following table]
----------------------------------------------------------------------------------------------------------------
                                                             Applies to
            Citation                     Subject           subpart EEEEEEE               Explanation
----------------------------------------------------------------------------------------------------------------
Sec.   63.1(a)(1), (a)(2),       Applicability..........  Yes.............
 (a)(3), (a)(4), (a)(6),
 (a)(10)-(a)(12), (b)(1),
 (b)(3), (c)(1), (c)(2),
 (c)(5), (e).
Sec.   63.1(a)(5), (a)(7)-       Reserved...............  No..............
 (a)(9), (b)(2), (c)(3),
 (c)(4), (d).
Sec.   63.2....................  Definitions............  Yes.............
Sec.   63.3....................  Units and Abbreviations  Yes.............
Sec.   63.4....................  Prohibited Activities    Yes.............
                                  and Circumvention.
Sec.   63.5....................  Preconstruction Review   Yes.............
                                  and Notification
                                  Requirements.
Sec.   63.6(a), (b)(1)-(b)(5),   Compliance with          Yes.............
 (b)(7), (c)(1), (c)(2),          Standards and
 (c)(5), (e)(1)(iii), (f)(2),     Maintenance
 (f)(3), (g), (i), (j).           Requirements.
Sec.   63.6(e)(1)(i) and (ii),   Startup, Shutdown and    No..............  Subpart EEEEEEE standards apply at
 (e)(3), and (f)(1).              Malfunction                                all times.
                                  Requirements (SSM).

[[Page 22496]]

 
Sec.   63.6(h)(1), (h)(2),       Compliance with Opacity  No..............  Subpart EEEEEEE does not contain
 (h)(4), (h)(5)(i), (ii), (iii)   and Visible Emission                       opacity or visible emission limits.
 and (v), (h)(6)-(h)(9).          Limits.
Sec.   63.6(b)(6), (c)(3),       Reserved...............  No..............
 (c)(4), (d), (e)(2),
 (e)(3)(ii), (h)(3), (h)(5)(iv).
Sec.   63.7, except (e)(1).....  Applicability and        Yes.............
                                  Performance Test Dates.
Sec.   63.7(e)(1)..............  Performance Testing      No..............
                                  Requirements Related
                                  to SSM.
Sec.   63.8(a)(1), (b)(1),       Monitoring Requirements  Yes.............
 (f)(1)-(5), (g).
Sec.   63.8(a)(2), (a)(4),       Continuous Monitoring    Yes.............  Except cross references to SSM
 (b)(2)-(3), (c), (d), (e),       Systems.                                   requirements in Sec.   63.6(e)(1)
 (f)(6), (g).                                                                and (3) do not apply.
Sec.   63.8(a)(3)..............  [Reserved].............  No..............
Sec.   63.9(a), (b)(1),          Notification             Yes.............
 (b)(2)(i)-(v), (b)(4), (b)(5),   Requirements.
 (c), (d), (e), (g), (h)(1)-
 (h)(3), (h)(5), (h)(6), (i),
 (j).
Sec.   63.9(f).................  .......................  No..............
Sec.   63.9(b)(3), (h)(4)......  Reserved...............  No..............
Sec.   63.10(a), (b)(1),         Recordkeeping and        Yes.............
 (b)(2)(vi)-(xiv), (b)(3), (c),   Reporting Requirements.
 (d)(1)-(4), (e), (f).
Sec.   63.10(b)(2)(i)-(v),       Recordkeeping/Reporting  No..............
 (d)(5).                          Associated with SSM.
Sec.   63.10(c)(2)-(c)(4),       Reserved...............  No..............
 (c)(9).
Sec.   63.11...................  Control Device           No..............
                                  Requirements.
Sec.   63.12...................  State Authority and      Yes.............
                                  Delegations.
Sec.  Sec.   63.13-63.16.......  Addresses,               Yes.............
                                  Incorporations by
                                  Reference,
                                  Availability of
                                  Information,
                                  Performance Track
                                  Provisions.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2010-9363 Filed 4-27-10; 8:45 am]
BILLING CODE 6560-50-P


