DATE: 		July 23, 2019
SUBJECT: 	Taconite Iron Ore Processing  -  Ample Margin of Safety (AMOS) Analysis
FROM:		Mike Laney, RTI International
TO: 		Docket No. EPA-HQ-OAR-2017-0644, NESHAP for Taconite Iron Ore Processing
The results of the multipathway risk analysis indicate that of the eight taconite iron ore processing plants operating in Minnesota and Michigan, all but two have maximum individual risk (MIR) of between 1-in-1 million and 2-in-1 million. The drivers for these risks are metal hazardous air pollutants (HAP) from indurating furnaces. This memorandum documents the estimated costs of reducing emissions of metal HAP from indurating furnaces at the six taconite iron ore processing plants with MIRs in excess of 1-in-1 million. The six plants considered in this AMOS analysis and the number of processing lines at each plant and the metal HAP emissions in tons per year (tpy) from each plant are listed in Table 1.
       Table 1. Taconite Iron Ore Processing Plants  -  AMOS Analysis[a]
                                     Plant
                                Number of lines
                         Metal HAP emissions (tpy)[1]
Hibbing
                                       3
                                     1.09
US Steel - Minntac
                                       5
                                     4.54
United Taconite
                                       2
                                     1.13
Tilden
                                       2
                                     2.00
Empire
                                       3
                                     0.60
Northshore
                                       4
                                     1.10
                                     Total
                                      19
                                     10.46
[a] This table excludes the US Steel - Keetac and ArcelorMittal Minorca plants because they are not part of the AMOS analysis because their MIRs are already estimated to be less than 1-in-1 million.
Control Options
Due to the high moisture content of the exhaust gases from indurating furnaces, baghouses are not considered viable controls and particulate matter (PM) emissions (a surrogate for metal HAP emissions) are typically controlled using either high efficiency wet scrubbers or wet walled electrostatic precipitators (WWESP).
To evaluate the cost and cost effectiveness of measures to further reduce metal HAP emissions from indurating furnaces at the six taconite iron ore facilities with MIRs in excess of 1-in-1 million, the addition of a WWESP downstream of existing controls was evaluated.
Cost for Reducing Metal HAP Emissions from Indurating Furnaces
To conduct this AMOS analysis, information from the 2006 Best Available Control Technology (BART) reports prepared for the taconite facilities in Minnesota[2,3,4,5,6,7] was used. A BART analysis is required by the EPA as part of their regional haze rule for industrial facilities that emit air pollutants that reduce visibility. The BART reports used for this analysis contained cost estimates for installing WWESP for the reduction of PM emissions. The BART reports presented control costs either for each processing line at a taconite plant or for each stack of an indurating furnace. Because similar control costs were not available for the Tilden and Empire taconite plants in Michigan, the average cost per line was estimated using the cost data from all of the Minnesota plants and applied to the two Michigan plants. Although the AMOS analysis excludes the Keetac and Minorca plants, their cost information from the BART reports was used to estimate costs for the Michigan plants. Capital costs and annual costs from the BART reports that were used in this analysis are summarized in Attachment 1.
Cost effectiveness. The cost effectiveness of reducing metal HAP emissions from indurating furnaces is determined by dividing the total annual cost of additional controls by the amount of emission reductions achieved by the additional controls and is described below.
To calculate the total annual cost for each plant, the annual costs for individual lines at each plant from the BART analyses were summed. To estimate the costs for the Michigan plants that were not part of the BART analysis, the average of the annual per line costs from the Minnesota plants (about $7.2 million per year per production line) was multiplied by the number of production lines at the Michigan plants. The annual cost for each plant was then summed to get the total annual cost of $144.5 million for the taconite industry. Because costs from the BART reports were estimated for 2006, an inflation factor was applied to estimate 2014 costs, the year for which emissions were estimated. Factors for updating the cost were taken from Chemical Engineering Plant Cost Index (CECPI). For 2006, the factor was 499.6 and the factor for 2014 was 576.1. Applying the ratio of the indices for 2014/2006 brought the total industry cost up to $166.6 million.
Cost effectiveness was then calculated by dividing the total industry annual cost by the expected reduction in metal HAP emissions. To estimate emission reductions, a control efficiency of 99.9 percent[8] was used. The reduction in metal HAP emissions after applying WWESP is 10.45 tpy. The cost effectiveness for the industry was estimated at $15.9 million per ton of metal HAP removed. Table 2 summarizes the information used to estimate the cost effectiveness.
Table 2. Cost Effectiveness Results for AMOS Analysis for the Taconite Iron Ore Processing Industry
                               Taconite Facility
                         No. of Lines in AMOS Analysis
           Metal HAP emissions (tpy) from furnaces in AMOS analysis
                      Total Annual Cost of WWESP ($2006)
                     Total Annual Cost of WWESP ($2014)[3]
                Emission Reduction @ 99.9% Efficiency (tons/yr)
               Cost Effectiveness ($2014/ton emission reduction)
US Steel - Keetac. MN
                                                                              0
                                                                          NA[1]
                                                                          NA[1]
                                                                          NA[1]
                                                                          NA[1]
                                                                          NA[1]
Hibbing, MN
                                                                              3
                                                                           1.09
                                                                     28,745,360
                                                                     33,146,921
                                                                          1.089
                                                                     30,440,460
ArcelorMittal, MN
                                                                              0
                                                                          NA[1]
                                                                          NA[1]
                                                                          NA[1]
                                                                          NA[1]
                                                                          NA[1]
US Steel - Minntac, MN
                                                                              5
                                                                           4.54
                                                                     38,282,376
                                                                     44,144,269
                                                                          4.535
                                                                      9,733,140
United Taconite, MN
                                                                              2
                                                                           1.13
                                                                     25,415,930
                                                                     29,307,681
                                                                          1.129
                                                                     25,961,963
Northshore, MN
                                                                              4
                                                                           1.10
                                                                     16,046,370
                                                                     18,503,430
                                                                          1.099
                                                                     16,838,138
Tilden, MI[2]
                                                                              2
                                                                           2.00
                                                                     14,395,668
                                                                     16,599,969
                                                                          1.998
                                                                      8,308,293
Empire, MI[2]
                                                                              3
                                                                           0.60
                                                                     21,593,502
                                                                     24,899,953
                                                                          0.599
                                                                     41,541,463
Total
                                                                             19
                                                                          10.46
                                                                    144,479,206
                                                                    166,602,223
                                                                         10.450
                                                                     15,943,498
1 NA = not applicable. Not included in the AMOS analysis.
2 Control costs were not available for the Tilden and Empire facilities. The average of the costs/line from the BART analyses ($7,197,834) was multiplied by the number of lines at the Tilden and Empire facilities to calculate the total facility costs.
3 The 2006 costs from the BART analyses were updated to 2014 cost using the Chemical Engineering Plant Cost Index (CEPCI). 2006 CEPCI = 499.6; 2014 CEPCI = 576.1.
References
    Putney, David, US Environmental Protection Agency, Memorandum, "Development of the Residual Risk Review Emissions Dataset for the Taconite Iron Ore Processing Source Category," March 29, 2019.
    Hibbing Taconite Analysis of Best Available Control Technology (BART), no date.
    Minntac BART Report, September 8, 2006.
    United Taconite Analysis of Best Available Retrofit Technology (BART), August 30, 2006.
    Northshore Mining Company Analysis of Best Available Retrofit Technology (BART), September 6, 2006.
    Keetac BART Report, September 8, 2006.
    Mittal Steel BART Report, September 8, 2006.
    U.S. EPA, Wet Electrostatic Precipitator (ESP)  -  Wire-Pipe Type, Air Pollution Control Technology Fact Sheet, EPA-452/F-03-029, no date.

                                 Attachment 1
Capitol and Annual Costs ($2006) of Wet Walled ESPs (WWESP) for Taconite Iron Ore Processing
                                   Facility
                                   Location
                                   Line No.
                                       
                             Capitol cost ($/Line)
                             Annual Cost ($/Line)
                           Capitol cost ($/facility)
                           Annual Cost ($/facility)
Hibbing[1]
Hibbing
                                       1
                                       
                                                                     42,951,640
                                                                      9,337,928
                                                                    131,057,337
                                                                     28,745,360


                                       2
                                       
                                                                     43,604,738
                                                                      9,559,244




                                       3
                                       
                                                                     44,500,959
                                                                      9,848,188


Minntac[2]
Mountain Iron
                                       3
                                       
                                                                     27,948,027
                                                                      5,322,323
                                                                    180,807,847
                                                                     38,282,376


                                       4
                                       
                                                                     39,347,773
                                                                      8,448,332




                                       5
                                       
                                                                     39,347,773
                                                                      8,448,332




                                       6
                                       
                                                                     36,370,821
                                                                      7,939,628




                                       7
                                       
                                                                     37,793,453
                                                                      8,123,761


United Taconite[3]
Eveleth
                                       1
                                       
                                                                     29,805,809
                                                                      7,441,650
                                                                     71,427,421
                                                                     25,415,930


                                       2
                                       
                                                                     41,621,612
                                                                     17,974,280


Northshore[4]
Silver Bay
                                11 Hood Exhaust
                                       
                                                                     23,617,556
                                                                      4,188,875
                                                                     90,927,890
                                                                     16,046,370


                                 11 Waste Gas
 
                                                                     21,846,389
                                                                      3,799,211




                                12 Hood Exhaust
 
                                                                     23,617,556
                                                                      4,294,171




                                 12 Waste Gas
 
                                                                     21,846,389
                                                                      3,764,113


Keetac[5]
Keewatin
                              Indurating Furnace
 
                                                                     45,081,576
                                                                     11,531,318
                                                                     45,081,576
                                                                     11,531,318
ArcelorMittal[6]
Virginia
                                     SV014
 
                                                                     22,809,844
                                                                      4,184,373
                                                                     91,239,376
                                                                     16,737,492


                                     SV015
 
                                                                     22,809,844
                                                                      4,184,373




                                     SV016
 
                                                                     22,809,844
                                                                      4,184,373




                                     SV017
 
                                                                     22,809,844
                                                                      4,184,373


                                   Total ($)
 
                                                                    610,541,447
                                                                    136,758,846
                                                                    610,541,447
                                                                    136,758,846
                               Average 
($/unit)
 
                                                                     32,133,760
                                                                      7,197,834
                                                                              
                                                                              
Source:
1 Hibbing Taconite Analysis of Best Available Control Technology (BART), no date.
2 Minntac BART Report, September 8, 2006.
3 United Taconite Analysis of Best Available Retrofit Technology (BART), August 30, 2006.
4 Northshore Mining Company Analysis of Best Available Retrofit Technology (BART), September 6, 2006.
5 Keetac BART Report, September 8, 2006.
6 Mittal Steel BART Report, September 8, 2006.
