SV 001 EU 001 Power Boiler 1 (Combusting Western Coal) 517 [101]4,528,920 [102]MMBtu NOx 0.71 [103] 364.94[112] 1,598.44 [113] 0 [114] 364.94 [116] 1,598.44 [121] SV 001 EU 001 517 [101]4,528,920 [102]MMBtu SO2 [104] 1,292.50 [112] 3,396.69 [113] 0 [114] 1,292.50 [116] 3,396.69 [121] SV 001 EU 001 Power Boiler 1 (Combusting Distillate Fuel Oil) 517 [101]4,528,920 [102]MMBtu NOx 0.15 [105] 76.03 [112] 333.01 [113] 0 [114] 76.03 [116] 333.01 [121] SV 001 EU 001 517 [101]4,528,920 [102]MMBtu SO2 0.21 [106] 109.63 [112] 480.20 [113] 0 [114] 109.63 [116] 480.20 [121] SV 001 EU 001 Power Boiler 1 (Combusting Natural Gas) 517 [101]4,528,920 [102]MMBtu NOx 0.9 [107] 465.30 [112] 2,038.01 [113] 0 [114] 465.30 [116] 2,038.01 [121] SV 001 EU 001 517 [101]4,528,920 [102]MMBtu SO2 0.0006 [108] 0.30 [112] 1.29 [113] 0 [114] 0.30 [116] 1.29 [121] SV 002 EU 002 Power Boiler 2 (Combusting Western Coal) 765 [101]6,701,400 [102]MMBtu NOx 0.71 [103] 540.00 [112] 2,365.20 [113] 0 [114] 540.00 [116] 2,365.20 [121] SV 002 EU 002 765 [101]6,701,400 [102]MMBtu SO2 [104] 1,912.50 [112] 5,026.05 [113] 0 [114] 1,912.50 [116] 5,026.05 [121] SV 002 EU 002 Power Boiler 2 (Combusting Natural Gas) 765 [101]6,701,400 [102]MMBtu NOx 0.9 [107] 688.50 [112] 3,015.63 [113] 0 [114] 688.50 [116] 3,015.63 [121] SV 002 EU 002 765 [101]6,701,400 [102]MMBtu SO2 0.0006 [108] 0.44[112] 1.91 [113] 0 [114] 0.44 [116] 1.91 [121] SV 003 EU 003 Process Boiler 1 (Combusting Distillate Fuel Oil) 79 [101] 692,040 [102]MMBtu NOx 0.15 [105] 11.62 [112] 50.89 [113] 0 [114] 11.62 [116] 50.89 [121] SV 003 EU 003 79 [101] 692,040 [102]MMBtu SO2 0.21 [106] 16.75 [112] 73.38 [113] 0 [114] 16.75 [116] 73.38 [121] SV 003 EU 003 Process Boiler 1 (Combusting Natural Gas) 79 [101] 692,040 [102]MMBtu NOx 0.095 [109] 7.52 [112] 32.95 [113] 0 [114] 7.52 [116] 32.95 [121] SV 003 EU 003 79 [101] 692,040 [102]MMBtu SO2 0.0006 [108] 0.05 [112] 0.20 [113] 0 [114] 0.05 [116] 0.20 [121] SV 003 EU 004 Process Boiler 2 (Combusting Distillate Fuel Oil) 79 [101] 692,040 [102]MMBtu NOx 0.15 [105] 11.62 [112] 50.89 [113] 0 [114] 11.62 [116] 50.89 [121] SV 003 EU 004 79 [101] 692,040 [102]MMBtu SO2 0.21 [106] 16.75 [112] 73.38 [113] 0 [114] 16.75 [116] 73.38 [121] SV 003 EU 004 Process Boiler 2 (Combusting Natural Gas) 79 [101] 692,040 [102]MMBtu NOx 0.095 [109] 7.52 [112] 32.95 [113] 0 [114] 7.52 [116] 32.95 [121] SV 003 EU 004 79 [101] 692,040 [102]MMBtu SO2 0.0006 [108] 0.05 [112] 0.20 [113] 0 [114] 0.05 [116] 0.20 [121] SVs 101-103 EU 100 Furnace 11 Hood Exhaust 160 [101] 1,401,600 [102]MMBtu NOx 0.3201 [110] 51.22 [112] 224.33 [113] 0 [114] 51.22 [117] 224.33 [122] SVs 101-103 EU 100 160 [101] 1,401,600 [102]MMBtu SO2 1.1077 [110] 177.22 [112] 776.24[113] 80 [115] 35.44 [118] 155.25 [122] SVs 104-105 EU 104 Furnace 11 Waste Gas 160 [101] 1,401,600 [102]MMBtu NOx 0.7799 [110] 124.78 [112] 546.55 [113] 0 [114] 124.78 [117] 546.55 [122] SVs 104-105 EU 104 160 [101] 1,401,600 [102]MMBtu SO2 0.3692 [110] 59.07 [112] 258.75 [113] 80 [115] 11.81 [118] 51.75 [122] SVs 111-113 EU 110 Furnace 12 Hood Exhaust 160 [101] 1,401,600 [102]MMBtu NOx 0.3201 [110] 51.22 [112] 224.33 [113] 0 [114] 51.22 [117] 224.33 [122] SVs 111-113 EU 110 160 [101] 1,401,600 [102]MMBtu SO2 1.1077 [110] 177.22 [112] 776.24[113] 80 [115] 35.44 [118] 155.25 [122] SVs 114-115 EU 114 Furnace 12 Waste Gas 160 [101] 1,401,600 [102]MMBtu NOx 0.7799 [110] 124.78 [112] 546.55 [113] 0 [114] 124.78 [117] 546.55 [122] SVs 114-115 EU 114 160 [101] 1,401,600 [102]MMBtu SO2 0.3692 [110] 59.07 [112] 258.75 [113] 80 [115] 11.81 [118] 51.75 [122] SVs 266-268 EU 634 Furnace 5 H.E./Waste Gas 100 [101] 876,000 [102]MMBtu NOx 0.4565 [110] 45.65 [112] 199.97 [113] 0 [114] 45.65 [119] 199.97 [122] SVs 266-268 EU 634 100 [101] 876,000 [102]MMBtu SO2 0.6373 [110] 63.73 [112] 279.12 [113] 80 [115] 12.75 [120] 55.82 [122] SVs 261-263 EU 262 Furnace 6 H.E./Waste Gas 100 [101] 876,000 [102]MMBtu NOx 0.4565 [110] 45.65 [112] 199.97 [113] 0 [114] 45.65 [119] 199.97 [122] SVs 261-263 EU 262 100 [101] 876,000 [102]MMBtu SO2 0.6490 [110] 64.90 [112] 284.25 [113] 80 [115] 12.98 [120] 56.85 [122]

Total NOx: 1,620.3[123] 7,097.1[125] 1,620.3[127] 7,097.1[129] Total SO2: 3,839.7[124] 11,202.8[126] 3,358.7[128] 9,096.2[130]

**Notes:** [101] Maximum hourly throughput = Design capacity of emission unit: For Furnaces 11 and 12, 10 MM Btu/hr is added to account for producing flux pellets at a heat input greater than the furnaces' design capacities.

Power Boiler 1 517MM Btu/hr Power Boiler 2 765MM Btu/hr Process Boiler 1 79MM Btu/hr Process Boiler 2 79MM Btu/hr Furnace 11 160MM Btu/hr Furnace 12 160MM Btu/hr Furnace 5 100MM Btu/hr Furnace 6 100MM Btu/hr [102] Maximum annual throughput = Maximum hourly throughput x 8,760 hours/yr. [103] AP-42, September 1998, Table 1.1-3 for 'PC-fired, dry bottom, wall-fired, bituminous, NSPS', converted from lbs/ton to lbs/MM Btu using the heat content in [111]. [104] Permit limit specified in permit 0750003-002, issued 9/29/2004: 2.5lbs/MM Btu for 1-hour average 1.5lbs/MM Btu for annual average [105] AP-42, September 1998, Table 1.3-1 for 'Commercial/institutional, Distillate oil fired', converted from lbs/ton to lbs/MM Btu using the heat content in [111]. [106] Assumes all S in fuel is converted to SO2: 0.002 lb S/lb fuel x 7.21 lb fuel/gal / 0.136 MM Btu/gal x 64 lb SO2/32 lb S (fuel data from Northshore Mining) [107] Based on results of stack test performed 5/27/94 on SV 002 (0.7 lb/MM Btu) while burning natural gas (worst case fuel for NOx), rounded to 0.9 lb/MM Btu. [108] AP-42, March 1998, Table 1.4-2. [109] AP-42, March 1998, Table 1.4-1 for 'Small Boilers (< 100 MM Btu/hr), Uncontrolled'. [110] Uncontrolled emission factor (lbs/MM Btu) is back-calculated as Maximum Controlled Emissions (lbs/hr) / ((100-Control Eff.)/100) / Maximum Hourly Throughput (MM Btu/hr) [111] Maximum hourly throughput = Design Heat input of emission unit (MM Btu/hr), Western Coal 17.0MM Btu/ton (from Northshore Mining Company) Distillate fuel oil 136MM Btu/1000 gals (from Northshore Mining Company) Natural gas 1,050MM Btu/MM cf (from AP-42, September 1995, Appendix A) [112] Maximum Uncontrolled Emissions (lbs/hr) = Maximum Hourly Throughput (units/hr) x Uncontrolled Emission Factor (lbs/unit). (%) (lbs/hr) (tons/yr) **Stack ID Emission Unit**  **Throughput Pollutant**  **Emission Factor** 

# Northshore Mining Company **Table 1: Facility-wide Potential to Emit Calculations for NOx and SO2**

**Maximum Uncontrolled Emissions Control Efficiency**  **Maximum Controlled Emissions ID**  **Description Maximum**  **Units** (Units/hr) (Units/yr) (lbs/Unit) (lbs/hr) (tons/yr)

# Northshore Mining Company **Table 1: Facility-wide Potential to Emit Calculations for NOx and SO2**

[113] Maximum Uncontrolled Emissions (tons/yr) = Maximum Annual Throughput (units/yr) x Uncontrolled Emission Factor (lbs/unit) / 2,000 (lbs/ton). [114] Either no Air Pollution Control Devices (APCDs) are used in this process or the APCD is ineffective for this pollutant. [115] Control Efficiency for a wet wall Electrostatic Precipitator (WWESP). [116] Maximum Controlled Emissions (lbs/hr) = Maximum Uncontrolled Emissions (lbs/hr) x ((100-Control Eff.)/100). [117] Based on results of stack test performed 1/8/1992 on Furnace 12. Emission factor = 1.1 lb/MM Btu x 160 MM Btu/hr = 176 lb/hr which is split between EU 100 and EU 104 (and EU 110 and EU 114) in the ratio 0.291:0.709. [118] Based on a S mass balance from fuel oil, concentrate, bentonite and fluxstone performed by Mike Osmundson, Northshore Mining, 8/7/1998. SO2 emissions (5.96 g/s) are distributed between the hood exhaust stacks and the waste gas stacks in the ratio 75:25. [119] Based on the result of a stack test performed 10/10/1995 on one of the three Furnace 6 stacks (12.2333 lbs/hr from SV 263) x 3 stacks x safety factor of 1.15.

[121] Maximum Controlled Emissions (tons/yr) = Maximum Uncontrolled Emissions (tons/yr) x ((100-Control Eff.)/100). [122] Maximum Controlled Emissions (tons/yr) = Maximum Controlled Emissions (lbs/hr) x 8,760 hours/yr / 2,000 lbs/ton. [123] Facility-wide Maximum Uncontrolled NOx emissions (lbs/hr) only considering worst-case fuel scenarios [124] Facility-wide Maximum Uncontrolled SO2 emissions (lbs/hr) only considering worst-case fuel scenarios [125] Facility-wide Maximum Uncontrolled NOx emissions (tons/yr) only considering worst-case fuel scenarios [126] Facility-wide Maximum Uncontrolled SO2 emissions (tons/yr) only considering worst-case fuel scenarios [127] Facility-wide Maximum Controlled NOx emissions (lbs/hr) only considering worst-case fuel scenarios [128] Facility-wide Maximum Controlled SO2 emissions (lbs/hr) only considering worst-case fuel scenarios [129] Facility-wide Maximum Controlled NOx emissions (tons/yr) only considering worst-case fuel scenarios [130] Facility-wide Maximum Controlled SO2 emissions (tons/yr) only considering worst-case fuel scenarios [120] Based on the result of a stack test performed 10/10/1995 on one of the three Furnace 6 (firing natural gas) stacks (1.08 lbs/hr from SV 263) x 3 stacks, adjusted to account for SO2 emissions from firing fuel oil. The latter assumes 0.4 % S in fuel oil and a density of 6.975 lbs/gallon.