# APPENDIX II **SUMMARY OF TEST RESULTS SUMMARY OF TEST RESULTS** 

**POTLINE 1-4 STACK Method 315** 
**[Raw Data]**
**Century Aluminum of Kentucky, LLC Hawesville, Kentucky** 

**Run Number 1 2 3 Mean**  Date Date of Test 3/13/2013 3/13/2013 3/13/2013 Start Start Time, Particulate Matter 9:05 AM 12:20 PM 3:35 PM - Stop Stop Time, Particulate Matter 12:05 PM 3:20 PM 6:35 PM - q Total Sampling Time, Particulate Matter 180.0 180.0 180.0 180.0 Pbar Barometric Pressure, in. Hg 29.65 29.65 30.00 29.77 Ds(w) Stack Diameter (Width), inches 311.75 311.75 311.75 311.75 Ds(d) Stack Diameter (Depth), inches 0.00 0.00 0.00 0.00 Dn Nozzle Diameter, inches 0.230 0.230 0.230 0.230 DP Average Velocity Head of Stack Gas, in. H2O 0.648 0.643 0.630 0.640 SQDP Average Squareroot Velocity Head of Stack Gas, 0.805 0.802 0.794 0.800

in. H2O DH Average Pressure Differential 1.75 1.76 1.72 1.74

Across the Orifice Meter, in. H2O Tm Absolute Dry Gas Meter Temperature, °F 44.8 51.9 49.2 49.0 Ts Absolute Stack Temperature, °F 73.8 74.9 74.7 74.0 Pg Stack Static Pressure, in. H2O 0.56 0.56 0.56 0.56 Vlc Total Volume of Water Vapor Condensed 59.7 54.6 62.4 58.9

in Impingers, ml Vwsg Total Volume of Water Vapor Condensed 17.0 16.9 21.1 18.3

in Silica Gel, g %CO2 Percent CO2 by Volume, Dry Basis 0.50 0.50 0.50 0.50 %O2 Percent O2 by Volume, Dry Basis 20.90 20.90 20.90 20.90 %CO Percent CO by Volume, Dry Basis 0.0 0.0 0.0 0.0 %N2 Percent N2 by Volume, Dry Basis 78.60 78.60 78.60 78.60 Vm Volume of Gas Sample as 118.429 130.225 128.174 125.609

measured by Dry Gas Meter, dcf Y Dry Gas Meter Calibration Factor 0.9968 0.9968 0.9968 0.9968 Cp Pitot Coefficient 0.84 0.84 0.84 0.84 Mn(PM) Particulate Matter Catch, ug 93,300 86,200 157,300 112,267 Mn(POM) POM Catch, ug 4,100 2,800 2,100 3,000 MW(C) Molecular Weight of Carbon, g/mole 12.00 12.00 12.00 12.00 MW(O2) Molecular Weight of Oxygen, g/mole 32.00 32.00 32.00 32.00 Tstd Standard Temperature, °R 528 528 528 528 Pstd Standard Pressure, in. Hg 29.92 29.92 29.92 29.92**SUMMARY OF TEST RESULTS**

**POTLINE 1-4 STACK Method 315** 
**[Flowrate Calculations]**
**Century Aluminum of Kentucky, LLC Hawesville, Kentucky** 

**Run Number 1 2 3 Mean**  An Cross Sectional Area of Nozzle, square feet 0.000289 0.000289 0.000289 0.000289 As Cross Sectional Area of Stack, square feet 530.08 530.08 530.08 530.08 Tm Absolute Dry Gas Meter Temperature, °R 505 512 509 509 Ts Absolute Stack Temperature, °R 534 535 535 535 Vmstd Volume of Gas Sample Measured by the Dry Gas 122.903 133.262 133.395 129.853

Meter, corrected to Standard Conditions, dscf Vwcstd Volume of Water Vapor Condensed in the Impingers, 2.81 2.57 2.94 2.77

Corrected to Standard Conditions Vwsgstd Volume of Water Vapor Condensed in the Silica Gel, 0.80 0.80 0.99 0.86

Corrected to Standard Conditions Bws Water Vapor in the Gas Stream, proportion 0.029 0.025 0.029 0.028

by volume Md Molecular Weight of Stack Gas, Dry Basis, lb/lb-mole 28.92 28.92 28.92 28.92 Ms Molecular Weight of Stack Gas, Wet Basis, lb/lb-mole 28.60 28.64 28.60 28.61 Ps Absolute Stack Gas Pressure, in. Hg 29.69 29.69 30.04 29.81 Vs Average Stack Gas Velocity, ft/sec 45.84 45.68 44.98 45.50 Qa Wet Volumetric Stack Gas Flow Rate at Actual 1,457,930 1,452,840 1,430,580 1,447,120

Conditions, acf/min Qa Wet Volumetric Stack Gas Flow Rate at Actual 87,475,900 87,170,600 85,834,800 86,827,100

Conditions, acf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 83,339,000 83,235,000 82,585,000 83,053,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 1,388,980 1,387,250 1,376,420 1,384,220

to Standard Conditions, dscf/min % I Isokinetics, % 90.2 97.9 98.8 95.6**SUMMARY OF TEST RESULTS**

**POTLINE 1-4 STACK Method 315** 
**[Pollutant Calculations]**
**Century Aluminum of Kentucky, LLC Hawesville, Kentucky** 

**Run Number 1 2 3 Mean** 
Cs(PM) Concentration of Particulate Matter, grains/dscf 1.17E-02 9.98E-03 1.82E-02 1.33E-02 Cs(POM) Concentration of POM, grains/dscf 5.15E-04 3.24E-04 2.43E-04 3.61E-04
Cs(PM) Concentration of Particulate Matter, mg/dscm 26.8 22.8 41.6 30.4 Cs(POM) Concentration of POM, mg/dscm 1.2 0.7 0.6 0.8
Mp(PM) Total Particulate Matter Emissions Rate, lbs/hour 139.5 118.7 214.7 157.6 Mp(POM) Total POM Emissions Rate, lbs/hour 6.13 3.86 2.87 4.28

PR(alum) Production Rate, ton/hour alum. equivalent **25.04 25.04 25.04 25.04** Mp(PM) Total Particulate Matter Emissions Rate,lbs/ton alum. Equivalent5.57 4.74 8.57 6.29 Mp(POM) Total POM Emissions Rate, lbs/ton alum. Equivalent 0.245 0.154 0.114 0.171**SUMMARY OF TEST RESULTS**

**POTLINE 1-4 STACK Method 315** 
**[Raw Data]**
**Century Aluminum of Kentucky, LLC Hawesville, Kentucky** 

**Run Number 4 5 6 Mean**  Date Date of Test 3/14/2013 3/14/2013 3/14/2013 Start Start Time, Particulate Matter 8:00 AM 11:15 AM 2:30 PM - Stop Stop Time, Particulate Matter 11:00 AM 2:15 PM 5:30 PM - q Total Sampling Time, Particulate Matter 180.0 180.0 180.0 180.0 Pbar Barometric Pressure, in. Hg 29.61 29.61 29.61 29.61 Ds(w) Stack Diameter (Width), inches 311.75 311.75 311.75 311.75 Ds(d) Stack Diameter (Depth), inches 0.00 0.00 0.00 0.00 Dn Nozzle Diameter, inches 0.230 0.230 0.230 0.230 DP Average Velocity Head of Stack Gas, in. H2O 0.633 0.623 0.653 0.636 SQDP Average Squareroot Velocity Head of Stack Gas, 0.796 0.789 0.808 0.800

in. H2O DH Average Pressure Differential 1.73 1.70 1.79 1.74

Across the Orifice Meter, in. H2O Tm Absolute Dry Gas Meter Temperature, °F 48.2 51.8 54.0 51.0 Ts Absolute Stack Temperature, °F 73.4 76.1 76.2 75.0 Pg Stack Static Pressure, in. H2O 0.52 0.52 0.54 0.53 Vlc Total Volume of Water Vapor Condensed 64.6 50.0 46.3 53.6

in Impingers, ml Vwsg Total Volume of Water Vapor Condensed 17.3 17.9 19.8 18.3

in Silica Gel, g %CO2 Percent CO2 by Volume, Dry Basis 0.50 0.50 0.50 0.50 %O2 Percent O2 by Volume, Dry Basis 20.90 20.90 20.90 20.90 %CO Percent CO by Volume, Dry Basis 0.0 0.0 0.0 0.0 %N2 Percent N2 by Volume, Dry Basis 78.60 78.60 78.60 78.60 Vm Volume of Gas Sample as 128.563 128.297 131.567 129.476

measured by Dry Gas Meter, dcf Y Dry Gas Meter Calibration Factor 0.9968 0.9968 0.9968 0.9968 Cp Pitot Coefficient 0.84 0.84 0.84 0.84 Mn(PM) Particulate Matter Catch, ug 113,200 123,100 199,200 145,167 Mn(POM) POM Catch, ug 4,500 1,100 2,900 2,833 MW(C) Molecular Weight of Carbon, g/mole 12.00 12.00 12.00 12.00 MW(O2) Molecular Weight of Oxygen, g/mole 32.00 32.00 32.00 32.00 Tstd Standard Temperature, °R 528 528 528 528 Pstd Standard Pressure, in. Hg 29.92 29.92 29.92 29.92**SUMMARY OF TEST RESULTS**

**POTLINE 1-4 STACK Method 315** 
**[Flowrate Calculations]**
**Century Aluminum of Kentucky, LLC Hawesville, Kentucky** 

**Run Number 4 5 6 Mean**  An Cross Sectional Area of Nozzle, square feet 0.000289 0.000289 0.000289 0.000289 As Cross Sectional Area of Stack, square feet 530.08 530.08 530.08 530.08 Tm Absolute Dry Gas Meter Temperature, °R 508 512 514 511 Ts Absolute Stack Temperature, °R 533 536 536 535 Vmstd Volume of Gas Sample Measured by the Dry Gas 132.331 131.119 133.915 132.455

Meter, corrected to Standard Conditions, dscf Vwcstd Volume of Water Vapor Condensed in the Impingers, 3.04 2.35 2.18 2.52

Corrected to Standard Conditions Vwsgstd Volume of Water Vapor Condensed in the Silica Gel, 0.82 0.84 0.93 0.86

Corrected to Standard Conditions Bws Water Vapor in the Gas Stream, proportion 0.028 0.024 0.023 0.025

by volume Md Molecular Weight of Stack Gas, Dry Basis, lb/lb-mole 28.92 28.92 28.92 28.92 Ms Molecular Weight of Stack Gas, Wet Basis, lb/lb-mole 28.61 28.65 28.66 28.64 Ps Absolute Stack Gas Pressure, in. Hg 29.65 29.65 29.65 29.65 Vs Average Stack Gas Velocity, ft/sec 45.29 45.02 46.09 45.47 Qa Wet Volumetric Stack Gas Flow Rate at Actual 1,440,440 1,431,850 1,465,880 1,446,060

Conditions, acf/min Qa Wet Volumetric Stack Gas Flow Rate at Actual 86,426,400 85,911,100 87,953,000 86,763,500

Conditions, acf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 82,467,000 81,852,000 83,884,000 82,734,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 1,374,450 1,364,200 1,398,070 1,378,910

to Standard Conditions, dscf/min % I Isokinetics, % 98.1 97.9 97.6 97.9**SUMMARY OF TEST RESULTS**

**POTLINE 1-4 STACK Method 315** 
**[Pollutant Calculations]**
**Century Aluminum of Kentucky, LLC Hawesville, Kentucky** 

**Run Number 4 5 6 Mean** 
Cs(PM) Concentration of Particulate Matter, grains/dscf 1.32E-02 1.45E-02 2.30E-02 1.69E-02 Cs(POM) Concentration of POM, grains/dscf 5.25E-04 1.29E-04 3.34E-04 3.29E-04

Cs(PM) Concentration of Particulate Matter, mg/dscm 30.2 33.1 52.5 38.6 Cs(POM) Concentration of POM, mg/dscm 1.2 0.3 0.8 0.8

Mp(PM) Total Particulate Matter Emissions Rate, lbs/hour 155.5 169.4 275.1 200.0 Mp(POM) Total POM Emissions Rate, lbs/hour 6.18 1.51 4.01 3.90

PR(alum) Production Rate, ton/hour alum. equivalent **25.04 25.04 25.04 25.04** Mp(PM) Total Particulate Matter Emissions Rate,lbs/ton alum. Equivalent6.21 6.77 10.99 7.99 Mp(POM) Total POM Emissions Rate, lbs/ton alum. Equivalent 0.247 0.060 0.160 0.156**SUMMARY OF TEST RESULTS**

**POTLINE 1-4 STACK EPA Method 29** 
**[Raw Data]**
**Century Aluminum of Kentucky, LLC Hawesville, Kentucky** 

**Run Number 1 2 3 Mean**  Date Date of Test 3/12/2013 3/12/2013 3/12/2013 Start Start Time, Metals 8:30 AM 12:40 PM 4:55 PM - Stop Stop Time, Metals 12:33 PM 4:43 PM 8:59 PM - q Total Sampling Time, 240.0 240.0 240.0 240.0 Pbar Barometric Pressure, in. Hg 29.25 29.25 29.35 29.28 Ds(w) Stack Diameter (Width), inches 311.75 311.75 311.75 311.75 Ds(d) Stack Diameter (Depth), inches 0.00 0.00 0.00 0.00 Dn Nozzle Diameter, inches 0.225 0.225 0.225 0.225 DP Average Velocity Head of Stack Gas, in. H2O 0.60 0.60 0.62 0.61 SQDP Average Squareroot Velocity Head of Stack Gas, 0.78 0.78 0.79 0.78

in. H2O DH Average Pressure Differential 1.71 1.73 1.75 1.73

Across the Orifice Meter, in. H2O Tm Absolute Dry Gas Meter Temperature, °F 59.2 63.5 60.6 61.0 Ts Absolute Stack Temperature, °F 77 79 79 78 Pg Stack Static Pressure, in. H2O 0.55 0.55 0.56 0.55 Vlc Total Volume of Water Vapor Condensed 59.3 85.1 102.1 82.2

in Impingers, ml Vwsg Total Volume of Water Vapor Condensed 19.5 24.8 19.6 21.3

in Silica Gel, g %CO2 Percent CO2 by Volume, Dry Basis 0.50 0.50 0.50 0.50 %O2 Percent O2 by Volume, Dry Basis 20.90 20.90 20.90 20.90 %CO Percent CO by Volume, Dry Basis 0.0 0.0 0.0 0.0 %N2 Percent N2 by Volume, Dry Basis 78.60 78.60 78.60 78.60 Vm Volume of Gas Sample as 160.247 168.572 160.623 163.147

measured by Dry Gas Meter, dcf Y Dry Gas Meter Calibration Factor 0.9968 0.9968 0.9968 0.9968 Cp Pitot Coefficient 0.84 0.84 0.84 0.84 Mn(An) Antimony, μg 2.16 0.89 0.95 0.00 Mn(As) Arsenic, μg 4.33 4.94 4.19 4.49 Mn(Be) Beryllium, μg 6.84 7.36 5.51 6.57 Mn(Cd) Cadmium, μg 1.67 1.72 1.06 1.48 Mn(Cr) Chromium, μg 12.20 14.90 4.80 10.63 Mn(Co) Cobalt, μg 1.82 1.57 0.85 1.41 Mn(Pb) Lead, μg 22.10 24.10 20.30 22.17 Mn(Mn) Manganese, μg 14.40 12.70 9.71 12.27 Mn(Ni) Nickel, μg 69.10 41.80 24.10 45.00 Mn(Hg) Mercury, μg < 0.50 < 0.60 0.71 0.60 Mn(Se) Selenium, μg 0.683 0.71 1.77 1.05 MW(C) Molecular Weight of Carbon, g/mole 12.00 12.00 12.00 12.00 MW(O2) Molecular Weight of Oxygen, g/mole 32.00 32.00 32.00 32.00 Tstd Standard Temperature, °R 528 528 528 528 Pstd Standard Pressure, in. Hg 29.92 29.92 29.92 29.92**SUMMARY OF TEST RESULTS**

**POTLINE 1-4 STACK EPA Method 29** 
**[Flowrate Calculations]**
**Century Aluminum of Kentucky, LLC Hawesville, Kentucky** 

**Run Number 1 2 3 Mean**  An Cross Sectional Area of Nozzle, square feet 0.000276 0.000276 0.000276 0.000276 As Cross Sectional Area of Stack, square feet 530.08 530.08 530.08 530.08 Tm Absolute Dry Gas Meter Temperature, °R 519 524 521 521 Ts Absolute Stack Temperature, °R 537 539 539 538 Vmstd Volume of Gas Sample Measured by the Dry Gas 159.487 166.402 159.990 161.960

Meter, corrected to Standard Conditions, dscf Vwcstd Volume of Water Vapor Condensed in the Impingers, 2.79 4.01 4.81 3.87

Corrected to Standard Conditions Vwsgstd Volume of Water Vapor Condensed in the Silica Gel, 0.92 1.17 0.92 1.00

Corrected to Standard Conditions Bws Water Vapor in the Gas Stream, proportion 0.023 0.030 0.035 0.029

by volume Md Molecular Weight of Stack Gas, Dry Basis, lb/lb-mole 28.92 28.92 28.92 28.92 Ms Molecular Weight of Stack Gas, Wet Basis, lb/lb-mole 28.66 28.59 28.53 28.59 Ps Absolute Stack Gas Pressure, in. Hg 29.29 29.29 29.39 29.32 Vs Average Stack Gas Velocity, ft/sec 44.60 44.66 45.44 44.90 Qa Wet Volumetric Stack Gas Flow Rate at Actual 1,418,490 1,420,400 1,445,210 1,428,030

Conditions, acf/min Qa Wet Volumetric Stack Gas Flow Rate at Actual 85,109,600 85,224,100 86,712,600 85,682,100

Conditions, acf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 80,037,000 79,275,000 80,518,000 79,943,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 1,333,950 1,321,250 1,341,970 1,332,390

to Standard Conditions, dscf/min % I Isokinetics, % 95.7 100.8 95.4 97.3**SUMMARY OF TEST RESULTS**

**POTLINE 1-4 STACK EPA Method 29** 
**[Pollutant Calculations]**
**Century Aluminum of Kentucky, LLC Hawesville, Kentucky** 

**Run Number 1 2 3 Mean**  Cs(An) Concentration of Antimony, grains/dscf 2.10E-07 8.00E-08 9.00E-08 1.30E-07 Cs(As) Concentration of Arsenic , grains/dscf 4.20E-07 4.60E-07 4.00E-07 4.30E-07 Cs(Be) Concentration of Beryllium, grains/dscf 6.60E-07 6.80E-07 5.30E-07 6.20E-07 Cs(Cd) Concentration of Cadmium, grains/dscf 1.60E-07 1.60E-07 1.00E-07 1.40E-07 Cs(Cr) Concentration of Chromium, grains/dscf 1.18E-06 1.38E-06 4.60E-07 1.01E-06 Cs(Co) Concentration of Cobalt, grains/dscf 1.80E-07 1.50E-07 8.00E-08 1.40E-07 Cs(Pb) Concentration of Lead, grains/dscf 2.14E-06 2.24E-06 1.96E-06 2.11E-06 Cs(Mn) Concentration of Manganese, grains/dscf 1.39E-06 1.18E-06 9.40E-07 1.17E-06 Cs(Ni) Concentration of Nickel, grains/dscf 6.69E-06 3.88E-06 2.32E-06 4.30E-06 Cs(Hg) Concentration of Mercury, grains/dscf < 5.00E-08 < 6.00E-08 7.00E-08 6.00E-08 Cs(Se) Concentration of Selenium, grains/dscf 7.00E-08 7.00E-08 1.70E-07 1.00E-07

Cs(An) Concentration of Antimony, mg/m3 4.80E-04 1.83E-04 2.06E-04 2.90E-04 Cs(As) Concentration of Arsenic, mg/m3 9.61E-04 1.05E-03 9.15E-04 9.76E-04 Cs(Be) Concentration of Beryllium, mg/m3 1.51E-03 1.56E-03 1.21E-03 1.43E-03 Cs(Cd) Concentration of Cadmium, mg/m3 3.66E-04 3.66E-04 2.29E-04 3.20E-04 Cs(Cr) Concentration of Chromium, mg/m3 2.70E-03 3.16E-03 1.05E-03 2.30E-03 Cs(Co) Concentration of Cobalt, mg/m3 4.12E-04 3.43E-04 1.83E-04 3.13E-04 Cs(Pb) Concentration of Lead, mg/m3 4.90E-03 5.13E-03 4.48E-03 4.84E-03 Cs(Mn) Concentration of Manganese, mg/m3 3.18E-03 2.70E-03 2.15E-03 2.68E-03 Cs(Ni) Concentration of Nickel, mg/m3 1.53E-02 8.88E-03 5.31E-03 9.83E-03 Cs(Hg) Concentration of Mercury, mg/m3 < 1.14E-04 < 1.37E-04 1.60E-04 1.37E-04 Cs(Se) Concentration of Selenium, mg/m3 1.60E-04 1.60E-04 3.89E-04 2.36E-04

Mp(An) Total Antimony Emissions Rate, lb/hour 2.40E-03 9.06E-04 1.04E-03 1.45E-03 Mp(As) Total Arsenic Emissions Rate, lb/hour 4.80E-03 5.21E-03 4.60E-03 4.87E-03 Mp(Be) Total Beryllium Emissions Rate, lb/hour 7.55E-03 7.70E-03 6.10E-03 7.11E-03 Mp(Cd) Total Cadmium Emissions Rate, lb/hour 1.83E-03 1.81E-03 1.15E-03 1.60E-03 Mp(Cr) Total Chromium Emissions Rate, lb/hour 1.35E-02 1.56E-02 5.29E-03 1.15E-02 Mp(Co) Total Cobalt Emissions Rate, lb/hour 2.06E-03 1.70E-03 9.20E-04 1.56E-03 Mp(Pb) Total Lead Emissions Rate, lb/hour 2.45E-02 2.54E-02 2.25E-02 2.41E-02 Mp(Mn) Total Manganese Emissions Rate, lb/hour 1.59E-02 1.34E-02 1.08E-02 1.34E-02 Mp(Ni) Total Nickel Emissions Rate, lb/hour 7.65E-02 4.39E-02 2.67E-02 4.90E-02 Mp(Hg) Total Mercury Emissions Rate, lb/hour < 5.72E-04 < 6.80E-04 8.05E-04 6.85E-04 Mp(Se) Total Selenium Emissions Rate, lb/hour 8.00E-04 7.93E-04 1.96E-03 1.18E-03

PR(alum) Production Rate, ton/hour alum. equivalent **25.04 25.04 25.04 25.05** Mp(An) Total Antimony Emissions Rate,lbs/ton alum. Equivalent 9.59E-05 3.62E-05 4.13E-05 5.78E-05 Mp(As) Total Arsenic Emissions Rate, lbs/ton alum. Equivalent 1.92E-04 2.08E-04 1.84E-04 1.94E-04 Mp(Be) Total Beryllium Emissions Rate, lbs/ton alum. Equivalent 3.01E-04 3.07E-04 2.43E-04 2.84E-04 Mp(Cd) Total Cadmium Emissions Rate,lbs/ton alum. Equivalent 7.30E-05 7.24E-05 4.59E-05 6.38E-05 Mp(Cr) Total Chromium Emissions Rate,lbs/ton alum. Equivalent 5.39E-04 6.24E-04 2.11E-04 4.58E-04 Mp(Co) Total Cobalt Emissions Rate, lbs/ton alum. Equivalent 8.22E-05 6.78E-05 3.67E-05 6.22E-05 Mp(Pb) Total Lead Emissions Rate,lbs/ton alum. Equivalent 9.77E-04 1.01E-03 9.00E-04 9.63E-04 Mp(Mn) Total Manganese Emissions Rate, lbs/ton alum. Equivalent 6.35E-04 5.34E-04 4.32E-04 5.33E-04 Mp(Ni) Total Nickel Emissions Rate, lbs/ton alum. Equivalent 3.05E-03 1.75E-03 1.07E-03 1.96E-03 Mp(Hg) Total Mercury Emissions Rate, lbs/ton alum. Equivalent 2.28E-05 < 2.71E-05 3.21E-05 2.74E-05 Mp(Se) Total Selenium Emissions Rate,lbs/ton alum. Equivalent 3.20E-05 3.17E-05 7.81E-05 4.72E-05SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 29
[Raw Data]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 1 2 3 Mean Date Date of Test 3/12/2013 3/12-13/2013 3/13/2013 Start Start Time, Particulate Matter 7:00 PM 10:50 PM 2:40 AM - Stop Stop Time, Particulate Matter 10:30 PM 2:20 AM 6:10 AM - q Total Sampling Time, Particulate Matter 210.0 210.0 210.0 210.0 Pbar Barometric Pressure, in. Hg 29.90 29.90 29.90 29.90 Ds(w) Stack Diameter (Width), inches 14.00 14.00 14.00 14.00 Ds(d) Stack Diameter (Depth), inches 0.00 0.00 0.00 0.00 Dn Nozzle Diameter, inches 0.430 0.430 0.430 0.430 DP Average Velocity Head of Stack Gas, in. H2O 0.043 0.042 0.044 0.043 SQDP Average Squareroot Velocity Head of Stack Gas, 0.208 0.206 0.210 0.210

in. H2O DH Average Pressure Differential 1.661 1.633 1.709 1.670

Across the Orifice Meter, in. H2O Tm Absolute Dry Gas Meter Temperature, °F 64.3 64.5 60.5 63.0 Ts Absolute Stack Temperature, °F 52.5 49.8 43.8 49.0 Pg Stack Static Pressure, in. H2O -0.32 -0.32 -0.30 -0.31 Vlc Total Volume of Water Vapor Condensed 8.9 7.4 9.6 8.6

in Impingers, ml Vwsg Total Volume of Water Vapor Condensed 2.3 3.5 3.5 3.1

in Silica Gel, g %CO2 Percent CO2 by Volume, Dry Basis 0.10 0.10 0.10 0.10 %O2 Percent O2 by Volume, Dry Basis 20.70 20.70 20.70 20.70 %CO Percent CO by Volume, Dry Basis 0.0 0.0 0.0 0.0 %N2 Percent N2 by Volume, Dry Basis 79.20 79.20 79.20 79.20 Vm Volume of Gas Sample as 145.992 144.172 147.052 145.739

measured by Dry Gas Meter, dcf Y Dry Gas Meter Calibration Factor 1.0102 1.0102 1.0102 1.0102 Cp Pitot Coefficient 0.84 0.84 0.84 0.84 Mn(An) Antimony, μg < 0.20 0.387 0.355 0.314 Mn(As) Arsenic, μg 0.569 0.529 0.681 0.593 Mn(Be) Beryllium, μg 0.804 0.742 1.020 0.855 Mn(Cd) Cadmium, μg 0.242 0.232 0.338 0.271 Mn(Cr) Chromium, μg 4.900 5.310 8.690 6.300 Mn(Co) Cobalt, μg 1.970 1.300 1.100 1.457 Mn(Pb) Lead, μg 3.320 3.780 5.330 4.143 Mn(Mn) Manganese, μg 34.700 16.500 11.800 21.000 Mn(Ni) Nickel, μg 96.500 55.600 44.000 65.367 Mn(Hg) Mercury, μg < 0.500 < 0.500 < 0.500 0.500 Mn(Se) Selenium, μg 0.269 0.329 < 0.200 0.266 MW(C) Molecular Weight of Carbon, g/mole 12.00 12.00 12.00 12.00 MW(O2) Molecular Weight of Oxygen, g/mole 32.00 32.00 32.00 32.00 Tstd Standard Temperature, °R 528 528 528 528 Pstd Standard Pressure, in. Hg 29.92 29.92 29.92 29.92SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 29
[Flowrate Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 1 2 3 Mean An Cross Sectional Area of Nozzle, square feet 0.001008 0.001008 0.001008 0.001008 As Cross Sectional Area of Stack, square feet 1.07 1.07 1.07 1.07 Tm Absolute Dry Gas Meter Temperature, °R 524 525 521 523 Ts Absolute Stack Temperature, °R 513 510 504 509 Vmstd Volume of Gas Sample Measured by the Dry Gas 149.029 147.105 151.225 149.120

Meter, corrected to Standard Conditions, dscf Vwcstd Volume of Water Vapor Condensed in the Impingers, 0.42 0.35 0.45 0.41

Corrected to Standard Conditions Vwsgstd Volume of Water Vapor Condensed in the Silica Gel, 0.11 0.17 0.17 0.15

Corrected to Standard Conditions Bws Water Vapor in the Gas Stream, proportion 0.004 0.004 0.004 0.004

by volume Md Molecular Weight of Stack Gas, Dry Basis, lb/lb-mole 28.84 28.84 28.84 28.84 Ms Molecular Weight of Stack Gas, Wet Basis, lb/lb-mole 28.80 28.80 28.80 28.80 Ps Absolute Stack Gas Pressure, in. Hg 29.88 29.88 29.88 29.88 Vs Average Stack Gas Velocity, ft/sec 11.52 11.37 11.54 11.48 Qa Wet Volumetric Stack Gas Flow Rate at Actual 740 730 740 740

Conditions, acf/min Qa Wet Volumetric Stack Gas Flow Rate at Actual 44,400 43,800 44,500 44,200

Conditions, acf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 45,000 45,000 46,000 45,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 750 750 770 760

to Standard Conditions, dscf/min % I Isokinetics, % 99.5 98.9 99.0 99.1SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 29
[Flowrate Calculations]

Run Number 1 2 3 Mean Ts Absolute Roof Temperature, °F 89.2 85.4 82.5 85.7 Ts Absolute Roof Temperature, °R 549.2 545.4 542.5 545.7 Vs Average Roof Gas Velocity, ft/min * 80.20 86.00 85.0 83.7 As Cross Sectional Area of Roof, square feet 8,880.5 8,880.5 8,880.5 8,880.5 Qa Wet Volumetric Roof Gas Flow Rate at Actual 712,220.0 763,720.0 754,840.0 743,593.3

Conditions, acf/min Qa Wet Volumetric Roof Gas Flow Rate at Actual 42,732,966 45,823,380 45,290,550 44,615,632

Conditions, acf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 40,987,000 44,258,000 43,977,000 43,074,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 683,117 737,633 732,950 717,900

to Standard Conditions, dscf/min % I Isokinetics, % (As per EPA Method 14, Section 12.2.1) 87.3 80.3 82.5 83.4

*NOTE: Flow measured by plant anemometer.SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 29
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 1 2 3 Mean Cs(An) Concentration of Antimony, grains/dscf < 2.00E-08 4.00E-08 4.00E-08 3.00E-08 Cs(As) Concentration of Arsenic, grains/dscf 6.00E-08 6.00E-08 7.00E-08 6.00E-08 Cs(Be) Concentration of Beryllium, grains/dscf 8.00E-08 8.00E-08 1.00E-07 9.00E-08 Cs(Cd) Concentration of Cadmium, grains/dscf 3.00E-08 2.00E-08 3.00E-08 3.00E-08 Cs(Cr) Concentration of Chromium, grains/dscf 5.10E-07 5.60E-07 8.90E-07 6.50E-07 Cs(Co) Concentration of Cobalt, grains/dscf 2.00E-07 1.40E-07 1.10E-07 1.50E-07 Cs(Pb) Concentration of Lead, grains/dscf 3.40E-07 4.00E-07 5.40E-07 4.30E-07 Cs(Mn) Concentration of Manganese, grains/dscf 3.59E-06 1.73E-06 1.20E-06 2.17E-06 Cs(Ni) Concentration of Nickel, grains/dscf 9.99E-06 5.83E-06 4.49E-06 6.77E-06 Cs(Hg) Concentration of Mercury, grains/dscf < 5.00E-08 < 5.00E-08 < 5.00E-08 < 5.00E-08 Cs(Se) Concentration of Selenium, grains/dscf 3.00E-08 3.00E-08 < 2.00E-08 3.00E-08

Cs(An) Concentration of Antimony, mg/m3 < 4.58E-05 9.15E-05 9.15E-05 7.63E-05 Cs(As) Concentration of Arsenic, mg/m3 1.37E-04 1.37E-04 1.60E-04 1.45E-04 Cs(Be) Concentration of Beryllium, mg/m3 1.83E-04 1.83E-04 2.29E-04 1.98E-04 Cs(Cd) Concentration of Cadmium, mg/m3 6.86E-05 4.58E-05 6.86E-05 6.10E-05 Cs(Cr) Concentration of Chromium, mg/m3 1.17E-03 1.28E-03 2.04E-03 1.49E-03 Cs(Co) Concentration of Cobalt, mg/m3 4.58E-04 3.20E-04 2.52E-04 3.43E-04 Cs(Pb) Concentration of Lead, mg/m3 7.78E-04 9.15E-04 1.24E-03 9.76E-04 Cs(Mn) Concentration of Manganese, mg/m3 8.21E-03 3.96E-03 2.75E-03 4.97E-03 Cs(Ni) Concentration of Nickel, mg/m3 2.29E-02 1.33E-02 1.03E-02 1.55E-02 Cs(Hg) Concentration of Mercury, mg/m3 < 1.14E-04 < 1.14E-04 < 1.14E-04 < 1.14E-04 Cs(Se) Concentration of Selenium, mg/m3 6.86E-05 6.86E-05 < 4.58E-05 6.10E-05

Mp(An) Total Antimony Emissions Rate, lb/hour < 1.29E-07 2.57E-07 2.63E-07 2.16E-07 Mp(As) Total Arsenic Emissions Rate, lb/hour 3.86E-07 3.86E-07 4.60E-07 4.10E-07 Mp(Be) Total Beryllium Emissions Rate, lb/hour 5.14E-07 5.14E-07 6.57E-07 5.62E-07 Mp(Cd) Total Cadmium Emissions Rate, lb/hour 1.93E-07 1.29E-07 1.97E-07 1.73E-07 Mp(Cr) Total Chromium Emissions Rate, lb/hour 3.28E-06 3.60E-06 5.85E-06 4.24E-06 Mp(Co) Total Cobalt Emissions Rate, lb/hour 1.29E-06 9.00E-07 7.23E-07 9.70E-07 Mp(Pb) Total Lead Emissions Rate, lb/hour 2.19E-06 2.57E-06 3.55E-06 2.77E-06 Mp(Mn) Total Manganese Emissions Rate, lb/hour 2.31E-05 1.11E-05 7.89E-06 1.40E-05 Mp(Ni) Total Nickel Emissions Rate, lb/hour 6.42E-05 3.75E-05 2.95E-05 4.37E-05 Mp(Hg) Total Mercury Emissions Rate, lb/hour < 3.21E-07 < 3.21E-07 < 3.29E-07 < 3.24E-07 Mp(Se) Total Selenium Emissions Rate, lb/hour 1.93E-07 1.93E-07 < 1.31E-07 1.72E-07SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 29
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number Total Test Section Emissions Rate 1 2 3 Mean Mp(An) Total Antimony Emissions Rate, lb/hour < 1.17E-04 2.53E-04 2.51E-04 2.07E-04 Mp(As) Total Arsenic Emissions Rate, lb/hour 3.51E-04 3.79E-04 4.40E-04 3.90E-04 Mp(Be) Total Beryllium Emissions Rate, lb/hour 4.68E-04 5.06E-04 6.28E-04 5.34E-04 Mp(Cd) Total Cadmium Emissions Rate, lb/hour 1.76E-04 1.26E-04 1.88E-04 1.64E-04 Mp(Cr) Total Chromium Emissions Rate, lb/hour 2.99E-03 3.54E-03 5.59E-03 4.04E-03 Mp(Co) Total Cobalt Emissions Rate, lb/hour 1.17E-03 8.85E-04 6.91E-04 9.16E-04 Mp(Pb) Total Lead Emissions Rate, lb/hour 1.99E-03 2.53E-03 3.39E-03 2.64E-03 Mp(Mn) Total Manganese Emissions Rate, lb/hour 2.10E-02 1.09E-02 7.54E-03 1.32E-02 Mp(Ni) Total Nickel Emissions Rate, lb/hour 5.85E-02 3.69E-02 2.82E-02 4.12E-02 Mp(Hg) Total Mercury Emissions Rate, lb/hour < 2.93E-04 < 3.16E-04 < 3.14E-04 < 3.08E-04 Mp(Se) Total Selenium Emissions Rate, lb/hour 1.76E-04 1.90E-04 < 1.26E-04 1.64E-04 PR(alum) Production Rate, ton/hour alum. equivalent 1.75 1.75 1.75 1.75 Mp(An) Total Antimony Emissions Rate, lb/ton alum. Equivalent < 6.70E-05 1.45E-04 1.44E-04 1.19E-04 Mp(As) Total Arsenic Emissions Rate, lb/ton alum. Equivalent 2.01E-04 2.17E-04 2.52E-04 2.23E-04 Mp(Be) Total Beryllium Emissions Rate, lb/ton alum. Equivalent 2.68E-04 2.89E-04 3.60E-04 3.06E-04 Mp(Cd) Total Cadmium Emissions Rate, lb/ton alum. Equivalent 1.01E-04 7.24E-05 1.08E-04 9.36E-05 Mp(Cr) Total Chromium Emissions Rate, lb/ton alum. Equivalent 1.71E-03 2.03E-03 3.20E-03 2.31E-03 Mp(Co) Total Cobalt Emissions Rate, lb/ton alum. Equivalent 6.70E-04 5.07E-04 3.95E-04 5.24E-04 Mp(Pb) Total Lead Emissions Rate, lb/ton alum. Equivalent 1.14E-03 1.45E-03 1.94E-03 1.51E-03 Mp(Mn) Total Manganese Emissions Rate, lb/ton alum. Equivalent 1.20E-02 6.26E-03 4.31E-03 7.53E-03 Mp(Ni) Total Nickel Emissions Rate, lb/ton alum. Equivalent 3.35E-02 2.11E-02 1.61E-02 2.36E-02 Mp(Hg) Total Mercury Emissions Rate, lb/ton alum. Equivalent < 1.68E-04 < 1.81E-04 < 1.80E-04 < 1.76E-04 Mp(Se) Total Selenium Emissions Rate, lb/ton alum. Equivalent 1.01E-04 1.09E-04 < 7.19E-05 9.37E-05

Run Number Total Line Emissions Rate 1 2 3 Mean Mp(An) Total Antimony Emissions Rate, lb/hour < 4.68E-04 1.01E-03 1.01E-03 8.28E-04 Mp(As) Total Arsenic Emissions Rate, lb/hour 1.41E-03 1.52E-03 1.76E-03 1.56E-03 Mp(Be) Total Beryllium Emissions Rate, lb/hour 1.87E-03 2.02E-03 2.51E-03 2.14E-03 Mp(Cd) Total Cadmium Emissions Rate, lb/hour 7.03E-04 5.06E-04 7.54E-04 6.54E-04 Mp(Cr) Total Chromium Emissions Rate, lb/hour 1.19E-02 1.42E-02 2.24E-02 1.62E-02 Mp(Co) Total Cobalt Emissions Rate, lb/hour 4.68E-03 3.54E-03 2.76E-03 3.66E-03 Mp(Pb) Total Lead Emissions Rate, lb/hour 7.96E-03 1.01E-02 1.36E-02 1.05E-02 Mp(Mn) Total Manganese Emissions Rate, lb/hour 8.41E-02 4.38E-02 3.02E-02 5.27E-02 Mp(Ni) Total Nickel Emissions Rate, lb/hour 2.34E-01 1.47E-01 1.13E-01 1.65E-01 Mp(Hg) Total Mercury Emissions Rate, lb/hour <1.17E-03<1.26E-03<1.26E-03<1.23E-03 Mp(Se) Total Selenium Emissions Rate, lb/hour 7.03E-04 7.59E-04<5.03E-04 6.55E-04SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 315
[Raw Data]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 1 2 3 Mean Date Date of Test 3/12/2013 3/12-13/2013 3/13/2013 Start Start Time, Particulate Matter 7:00 PM 9:50 PM 12:45 AM - Stop Stop Time, Particulate Matter 9:30 PM 12:24 AM 3:15 AM - q Total Sampling Time, Particulate Matter 150.0 154.0 150.0 151.3 Pbar Barometric Pressure, in. Hg 29.90 29.90 29.90 29.90 Ds(w) Stack Diameter (Width), inches 14.00 14.00 14.00 14.00 Ds(d) Stack Diameter (Depth), inches 0.00 0.00 0.00 0.00 Dn Nozzle Diameter, inches 0.430 0.430 0.430 0.430 DP Average Velocity Head of Stack Gas, in. H2O 0.044 0.043 0.045 0.044 SQDP Average Squareroot Velocity Head of Stack Gas, 0.210 0.206 0.211 0.210

in. H2O DH Average Pressure Differential 1.606 1.562 1.630 1.600

Across the Orifice Meter, in. H2O Tm Absolute Dry Gas Meter Temperature, °F 61.2 63.4 61.2 62.0 Ts Absolute Stack Temperature, °F 52.6 49.9 48.7 50.0 Pg Stack Static Pressure, in. H2O -0.32 -0.32 -0.32 -0.32 Vlc Total Volume of Water Vapor Condensed 6.5 6.0 6.1 6.2

in Impingers, ml Vwsg Total Volume of Water Vapor Condensed 1.5 1.7 0.6 1.3

in Silica Gel, g %CO2 Percent CO2 by Volume, Dry Basis 0.10 0.10 0.10 0.10 %O2 Percent O2 by Volume, Dry Basis 20.70 20.70 20.70 20.70 %CO Percent CO by Volume, Dry Basis 0.0 0.0 0.0 0.0 %N2 Percent N2 by Volume, Dry Basis 79.20 79.20 79.20 79.20 Vm Volume of Gas Sample as 107.262 106.232 107.153 106.882

measured by Dry Gas Meter, dcf Y Dry Gas Meter Calibration Factor 1.0062 1.0062 1.0062 1.0062 Cp Pitot Coefficient 0.84 0.84 0.84 0.84 Mn(PM) Particulate Matter Catch, ug 10,700 8,400 8,100 9,100 Mn(POM) POM Catch, μg 3,000 3,400 2,000 2,800 MW(C) Molecular Weight of Carbon, g/mole 12.00 12.00 12.00 12.00 MW(O2) Molecular Weight of Oxygen, g/mole 32.00 32.00 32.00 32.00 Tstd Standard Temperature, °R 528 528 528 528 Pstd Standard Pressure, in. Hg 29.92 29.92 29.92 29.92SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 315
[Flowrate Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 1 2 3 Mean An Cross Sectional Area of Nozzle, square feet 0.001008 0.001008 0.001008 0.001008 As Cross Sectional Area of Stack, square feet 1.07 1.07 1.07 1.07 Tm Absolute Dry Gas Meter Temperature, °R 521 523 521 522 Ts Absolute Stack Temperature, °R 513 510 509 511 Vmstd Volume of Gas Sample Measured by the Dry Gas 109.694 108.172 109.589 109.152

Meter, corrected to Standard Conditions, dscf Vwcstd Volume of Water Vapor Condensed in the Impingers, 0.31 0.28 0.29 0.29

Corrected to Standard Conditions Vwsgstd Volume of Water Vapor Condensed in the Silica Gel, 0.07 0.08 0.03 0.06

Corrected to Standard Conditions Bws Water Vapor in the Gas Stream, proportion 0.003 0.003 0.003 0.003

by volume Md Molecular Weight of Stack Gas, Dry Basis, lb/lb-mole 28.84 28.84 28.84 28.84 Ms Molecular Weight of Stack Gas, Wet Basis, lb/lb-mole 28.81 28.81 28.81 28.81 Ps Absolute Stack Gas Pressure, in. Hg 29.88 29.88 29.88 29.88 Vs Average Stack Gas Velocity, ft/sec 11.63 11.39 11.65 11.56 Qa Wet Volumetric Stack Gas Flow Rate at Actual 750 730 750 740

Conditions, acf/min Qa Wet Volumetric Stack Gas Flow Rate at Actual 44,800 43,900 44,900 44,500

Conditions, acf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 46,000 45,000 46,000 46,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 770 750 770 760

to Standard Conditions, dscf/min % I Isokinetics, % 101.5 98.9 100.4 100.3SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 315
[Flowrate Calculations]

Run Number
1 2 3 Mean Ts Absolute Roof Temperature, °F 89.5 86.8 82.5 86.3 Ts Absolute Roof Temperature, °R 549.5 546.8 542.5 546.3 Vs Average Roof Gas Velocity, ft/min * 78.60 87.50 85.0 83.7 As Cross Sectional Area of Roof, square feet 8,880.5 8,880.5 8,880.5 8,880.5 Qa Wet Volumetric Roof Gas Flow Rate at Actual 698,010.0 777,040.0 754,840.0 743,296.7

Conditions, acf/min Qa Wet Volumetric Roof Gas Flow Rate at Actual 41,880,438 46,622,625 45,290,550 44,597,871

Conditions, acf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 40,148,000 44,915,000 43,977,000 43,013,333

to Standard Conditions, dscf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 669,133 748,583 732,950 716,889

to Standard Conditions, dscf/min % I Isokinetics, % (As per EPA Method 14, Section 12.2.1) 89.9 79.1 83.3 84.1

*NOTE: Flow measured by plant anemometer.SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 315
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 1 2 3 Mean
Cs(PM) Concentration of Particulate Matter , grains/dscf 1.51E-03 1.20E-03 1.14E-03 1.28E-03 Cs(POM) Concentration of POM, grains/dscf 4.22E-04 4.85E-04 2.82E-04 3.96E-04
Cs(PM) Concentration of Particulate Matter, mg/dscm 3.4 2.7 2.6 2.9 Cs(POM) Concentration of POM, mg/dscm 1.0 1.1 0.6 0.9
Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 9.89E-03 7.70E-03 7.50E-03 8.00E-03 Mp(POM) Total POM Emissions Rate, lbs/hour 2.77E-03 3.12E-03 1.85E-03 3.00E-03

SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 315
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number Total Test Section Emissions Rate 1 2 3 Mean Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 8.63 7.69 7.17 7.83 Mp(POM) Total POM Emissions Rate, lbs/hour 2.42 3.11 1.77 2.43 PR(alum) Production Rate, ton/hour alum. equivalent 1.75 1.75 1.75 1.75 Mp(PM) Total Particulate Matter Emissions Rate,lbs/ton alum. Equivalent 4.94 4.40 4.10 4.48 Mp(POM) Total POM Emissions Rate, lbs/ton alum. Equivalent 1.39 1.78 1.01 1.39

Run Number Total Line Emissions Rate 1 2 3 Mean Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 34.53 30.76 28.66 31.32 Mp(POM) Total POM Emissions Rate, lbs/hour 9.68 12.45 7.08 9.74SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 315
[Raw Data]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 4 5 6 Mean Date Date of Test 3/13/2013 3/13-14/2013 3/14/2013 Start Start Time, Particulate Matter 7:15 PM 10:00 PM 12:45 AM - Stop Stop Time, Particulate Matter 9:45 PM 12:30 AM 3:15 AM - q Total Sampling Time, Particulate Matter 150.0 150.0 150.0 150.0 Pbar Barometric Pressure, in. Hg 29.90 29.90 29.90 29.90 Ds(w) Stack Diameter (Width), inches 14.00 14.00 14.00 14.00 Ds(d) Stack Diameter (Depth), inches 0.00 0.00 0.00 0.00 Dn Nozzle Diameter, inches 0.430 0.430 0.430 0.430 DP Average Velocity Head of Stack Gas, in. H2O 0.046 0.043 0.044 0.044 SQDP Average Squareroot Velocity Head of Stack Gas, 0.214 0.206 0.209 0.210

in. H2O DH Average Pressure Differential 1.665 1.566 1.602 1.610

Across the Orifice Meter, in. H2O Tm Absolute Dry Gas Meter Temperature, °F 45.0 53.2 54.1 51.0 Ts Absolute Stack Temperature, °F 37.3 37.0 38.1 37.0 Pg Stack Static Pressure, in. H2O -0.30 -0.30 -0.30 -0.30 Vlc Total Volume of Water Vapor Condensed 5.7 6.0 6.3 6.0

in Impingers, ml Vwsg Total Volume of Water Vapor Condensed 0.8 0.8 0.9 0.8

in Silica Gel, g %CO2 Percent CO2 by Volume, Dry Basis 0.10 0.10 0.10 0.10 %O2 Percent O2 by Volume, Dry Basis 20.70 20.70 20.70 20.70 %CO Percent CO by Volume, Dry Basis 0.0 0.0 0.0 0.0 %N2 Percent N2 by Volume, Dry Basis 79.20 79.20 79.20 79.20 Vm Volume of Gas Sample as 106.391 103.387 104.387 104.722

measured by Dry Gas Meter, dcf Y Dry Gas Meter Calibration Factor 1.0062 1.0062 1.0062 1.0062 Cp Pitot Coefficient 0.84 0.84 0.84 0.84 Mn(PM) Particulate Matter Catch, ug 6,800 7,700 10,000 8,200 Mn(POM) POM Catch, μg 3,200 1,400 1,700 2,100 MW(C) Molecular Weight of Carbon, g/mole 12.00 12.00 12.00 12.00 MW(O2) Molecular Weight of Oxygen, g/mole 32.00 32.00 32.00 32.00 Tstd Standard Temperature, °R 528 528 528 528 Pstd Standard Pressure, in. Hg 29.92 29.92 29.92 29.92SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 315
[Flowrate Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 4 5 6 Mean An Cross Sectional Area of Nozzle, square feet 0.001008 0.001008 0.001008 0.001008 As Cross Sectional Area of Stack, square feet 1.07 1.07 1.07 1.07 Tm Absolute Dry Gas Meter Temperature, °R 505 513 514 511 Ts Absolute Stack Temperature, °R 497 497 498 497 Vmstd Volume of Gas Sample Measured by the Dry Gas 112.309 107.368 108.227 109.301

Meter, corrected to Standard Conditions, dscf Vwcstd Volume of Water Vapor Condensed in the Impingers, 0.27 0.28 0.30 0.28

Corrected to Standard Conditions Vwsgstd Volume of Water Vapor Condensed in the Silica Gel, 0.04 0.04 0.04 0.04

Corrected to Standard Conditions Bws Water Vapor in the Gas Stream, proportion 0.003 0.003 0.003 0.003

by volume Md Molecular Weight of Stack Gas, Dry Basis, lb/lb-mole 28.84 28.84 28.84 28.84 Ms Molecular Weight of Stack Gas, Wet Basis, lb/lb-mole 28.81 28.81 28.81 28.81 Ps Absolute Stack Gas Pressure, in. Hg 29.88 29.88 29.88 29.88 Vs Average Stack Gas Velocity, ft/sec 11.70 11.25 11.39 11.45 Qa Wet Volumetric Stack Gas Flow Rate at Actual 750 720 730 730

Conditions, acf/min Qa Wet Volumetric Stack Gas Flow Rate at Actual 45,100 43,300 43,900 44,100

Conditions, acf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 48,000 46,000 46,000 47,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 800 770 770 780

to Standard Conditions, dscf/min % I Isokinetics, % 100.0 99.5 99.2 99.6SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 315
[Flowrate Calculations]

Run Number
4 5 6 Mean Ts Absolute Roof Temperature, °F 77.0 74.0 74.3 75.1 Ts Absolute Roof Temperature, °R 537.0 534.0 534.3 535.1 Vs Average Roof Gas Velocity, ft/min * 81.80 58.90 64.70 68.5 As Cross Sectional Area of Roof, square feet 8,880.5 8,880.5 8,880.5 8,880.5 Qa Wet Volumetric Roof Gas Flow Rate at Actual 726,420.0 523,060.0 574,570.0 608,016.7

Conditions, acf/min Qa Wet Volumetric Roof Gas Flow Rate at Actual 43,585,494 31,383,687 34,474,101 36,481,094

Conditions, acf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 42,755,000 30,959,000 33,988,000 35,900,667

to Standard Conditions, dscf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 712,583 515,983 566,467 598,344

to Standard Conditions, dscf/min % I Isokinetics, % (As per EPA Method 14, Section 12.2.1) 86.9 116.0 106.9 103.3

*NOTE: Flow measured by plant anemometer.SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 315
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 4 5 6 Mean
Cs(PM) Concentration of Particulate Matter , grains/dscf 9.34E-04 1.11E-03 1.43E-03 1.16E-03 Cs(POM) Concentration of POM, grains/dscf 4.40E-04 2.01E-04 2.42E-04 2.94E-04
Cs(PM) Concentration of Particulate Matter, mg/dscm 2.1 2.5 3.3 2.6 Cs(POM) Concentration of POM, mg/dscm 1.0 0.5 0.6 0.7
Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 6.41E-03 7.27E-03 9.37E-03 8.00E-03 Mp(POM) Total POM Emissions Rate, lbs/hour 3.02E-03 1.32E-03 1.59E-03 2.00E-03

SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 315
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number Total Test Section Emissions Rate 4 5 6 Mean Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 5.71 4.89 6.92 5.84 Mp(POM) Total POM Emissions Rate, lbs/hour 2.69 0.89 1.18 1.58 PR(alum) Production Rate, ton/hour alum. equivalent 1.75 1.75 1.75 1.75 Mp(PM) Total Particulate Matter Emissions Rate,lbs/ton alum. Equivalent 3.27 2.80 3.96 3.34 Mp(POM) Total POM Emissions Rate, lbs/ton alum. Equivalent 1.54 0.51 0.67 0.91

Run Number Total Line Emissions Rate 4 5 6 Mean Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 22.83 19.58 27.69 23.37 Mp(POM) Total POM Emissions Rate, lbs/hour 10.74 3.56 4.71 6.34SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 17
[Raw Data]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 1 2 3 Mean Date Date of Test 5/7/2013 5/7-8/2013 5/8/2013 Start Start Time, Particulate Matter 5:30 PM 9:45 PM 2:00 AM - Stop Stop Time, Particulate Matter 9:30 PM 1:45 AM 6:00 AM - q Total Sampling Time, Particulate Matter 240.0 240.0 240.0 240.0 Pbar Barometric Pressure, in. Hg 29.90 29.90 29.90 29.90 Ds(w) Stack Diameter (Width), inches 14.00 14.00 14.00 14.00 Ds(d) Stack Diameter (Depth), inches 0.00 0.00 0.00 0.00 Dn Nozzle Diameter, inches 0.390 0.390 0.390 0.390 DP Average Velocity Head of Stack Gas, in. H2O 0.065 0.062 0.064 0.064 SQDP Average Squareroot Velocity Head of Stack Gas, 0.255 0.250 0.253 0.250

in. H2O DH Average Pressure Differential 1.576 1.526 1.575 1.560

Across the Orifice Meter, in. H2O Tm Absolute Dry Gas Meter Temperature, °F 87.8 83.3 81.3 84.0 Ts Absolute Stack Temperature, °F 82.6 74.7 69.6 76.0 Pg Stack Static Pressure, in. H2O -0.04 -0.04 -0.04 -0.04 Vlc Total Volume of Water Vapor Condensed 24.8 23.4 24.7 24.3

in Impingers, ml Vwsg Total Volume of Water Vapor Condensed 28.6 26.5 30.8 28.6

in Silica Gel, g %CO2 Percent CO2 by Volume, Dry Basis 0.10 0.10 0.10 0.10 %O2 Percent O2 by Volume, Dry Basis 20.70 20.70 20.70 20.70 %CO Percent CO by Volume, Dry Basis 0.0 0.0 0.0 0.0 %N2 Percent N2 by Volume, Dry Basis 79.20 79.20 79.20 79.20 Vm Volume of Gas Sample as 169.858 167.624 169.858 169.113

measured by Dry Gas Meter, dcf Y Dry Gas Meter Calibration Factor 1.0062 1.0062 1.0062 1.0062 Cp Pitot Coefficient 0.84 0.84 0.84 0.84 Mn(PM) Particulate Matter Catch, ug 22,928 13,498 16,685 17,700 MW(C) Molecular Weight of Carbon, g/mole 12.00 12.00 12.00 12.00 MW(O2) Molecular Weight of Oxygen, g/mole 32.00 32.00 32.00 32.00 Tstd Standard Temperature, °R 528 528 528 528 Pstd Standard Pressure, in. Hg 29.92 29.92 29.92 29.92SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 17
[Flowrate Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 1 2 3 Mean An Cross Sectional Area of Nozzle, square feet 0.000830 0.000830 0.000830 0.000830 As Cross Sectional Area of Stack, square feet 1.070 1.070 1.070 1.070 Tm Absolute Dry Gas Meter Temperature, °R 548 543 541 544 Ts Absolute Stack Temperature, °R 543 535 530 536 Vmstd Volume of Gas Sample Measured by the Dry Gas 165.262 164.419 167.246 165.642

Meter, corrected to Standard Conditions, dscf Vwcstd Volume of Water Vapor Condensed in the Impingers, 1.17 1.10 1.16 1.14

Corrected to Standard Conditions Vwsgstd Volume of Water Vapor Condensed in the Silica Gel, 1.35 1.25 1.45 1.35

Corrected to Standard Conditions Bws Water Vapor in the Gas Stream, proportion 0.015 0.014 0.015 0.015

by volume Md Molecular Weight of Stack Gas, Dry Basis, lb/lb-mole 28.84 28.84 28.84 28.84 Ms Molecular Weight of Stack Gas, Wet Basis, lb/lb-mole 28.68 28.69 28.68 28.68 Ps Absolute Stack Gas Pressure, in. Hg 29.90 29.90 29.90 29.90 Vs Average Stack Gas Velocity, ft/sec 14.57 14.16 14.28 14.34 Qa Wet Volumetric Stack Gas Flow Rate at Actual 940 910 920 920

Conditions, acf/min Qa Wet Volumetric Stack Gas Flow Rate at Actual 56,100 54,500 55,000 55,200

Conditions, acf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 54,000 53,000 54,000 54,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 900 880 900 890

to Standard Conditions, dscf/min % I Isokinetics, % 99.2 99.9 99.9 99.7SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 17
[Flowrate Calculations]

Run Number
1 2 3 Mean Ts Absolute Roof Temperature, °F 116.8 110.0 103.0 109.9 Ts Absolute Roof Temperature, °R 576.8 570.0 563.0 569.9 Vs Average Roof Gas Velocity, ft/min * 79.80 85.00 70.7 78.5 As Cross Sectional Area of Roof, square feet 8,821.3 8,821.3 8,821.3 8,821.3 Qa Wet Volumetric Roof Gas Flow Rate at Actual 703,940.0 749,810.0 623,670.0 692,473.3

Conditions, acf/min Qa Wet Volumetric Roof Gas Flow Rate at Actual 42,236,384 44,988,630 37,419,955 41,548,323

Conditions, acf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 38,728,000 41,743,000 35,152,000 38,541,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 645,467 695,717 585,867 642,350

to Standard Conditions, dscf/min % I Isokinetics, % (As per EPA Method 14, Section 12.2.1) 110.9 101.2 122.7 111.6

*NOTE: Flow measured by plant anemometer.SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 17
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 1 2 3 Mean
Cs(PM) Concentration of Particulate Matter , grains/dscf 2.14E-03 1.27E-03 1.54E-03 1.65E-03
Cs(PM) Concentration of Particulate Matter, mg/dscm 4.9 2.9 3.5 3.8
Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 1.65E-02 9.59E-03 1.19E-02 1.30E-02

SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 17
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number Total Test Section Emissions Rate 1 2 3 Mean Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 11.85 7.55 7.73 9.04 PR(alum) Production Rate, ton/hour alum. equivalent 1.57 1.57 1.57 1.57 Mp(PM) Total Particulate Matter Emissions Rate,lbs/ton alum. Equivalent 7.54 4.81 4.92 5.76

Run Number Total Line Emissions Rate 1 2 3 Mean Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 47.38 30.22 30.92 36.18SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 17
[Raw Data]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 4 5 6 Mean Date Date of Test 5/8/2013 5/8-9/2013 5/9/2013 Start Start Time, Particulate Matter 4:45 PM 9:00 PM 1:15 AM - Stop Stop Time, Particulate Matter 8:45 PM 1:00 AM 5:15 AM - q Total Sampling Time, Particulate Matter 240.0 240.0 240.0 240.0 Pbar Barometric Pressure, in. Hg 29.90 29.90 29.90 29.90 Ds(w) Stack Diameter (Width), inches 14.00 14.00 14.00 14.00 Ds(d) Stack Diameter (Depth), inches 0.00 0.00 0.00 0.00 Dn Nozzle Diameter, inches 0.390 0.390 0.390 0.390 DP Average Velocity Head of Stack Gas, in. H2O 0.064 0.050 0.062 0.059 SQDP Average Squareroot Velocity Head of Stack Gas, 0.253 0.224 0.249 0.240

in. H2O DH Average Pressure Differential 1.538 1.518 1.566 1.540

Across the Orifice Meter, in. H2O Tm Absolute Dry Gas Meter Temperature, °F 89.7 90.9 87.3 89.0 Ts Absolute Stack Temperature, °F 91.4 78.1 72.0 81.0 Pg Stack Static Pressure, in. H2O -0.04 -0.04 -0.04 -0.04 Vlc Total Volume of Water Vapor Condensed 18.5 20.0 23.5 20.7

in Impingers, ml Vwsg Total Volume of Water Vapor Condensed 22.9 20.9 21.6 21.8

in Silica Gel, g %CO2 Percent CO2 by Volume, Dry Basis 0.10 0.10 0.10 0.10 %O2 Percent O2 by Volume, Dry Basis 20.70 20.70 20.70 20.70 %CO Percent CO by Volume, Dry Basis 0.0 0.0 0.0 0.0 %N2 Percent N2 by Volume, Dry Basis 79.20 79.20 79.20 79.20 Vm Volume of Gas Sample as 169.181 169.094 171.280 169.852

measured by Dry Gas Meter, dcf Y Dry Gas Meter Calibration Factor 1.0062 1.0062 1.0062 1.0062 Cp Pitot Coefficient 0.84 0.84 0.84 0.84 Mn(PM) Particulate Matter Catch, ug 9,709 18,515 16,461 14,900 MW(C) Molecular Weight of Carbon, g/mole 12.00 12.00 12.00 12.00 MW(O2) Molecular Weight of Oxygen, g/mole 32.00 32.00 32.00 32.00 Tstd Standard Temperature, °R 528 528 528 528 Pstd Standard Pressure, in. Hg 29.92 29.92 29.92 29.92SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 17
[Flowrate Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 4 5 6 Mean An Cross Sectional Area of Nozzle, square feet 0.000830 0.000830 0.000830 0.000830 As Cross Sectional Area of Stack, square feet 1.07 1.07 1.07 1.07 Tm Absolute Dry Gas Meter Temperature, °R 550 551 547 549 Ts Absolute Stack Temperature, °R 551 538 532 540 Vmstd Volume of Gas Sample Measured by the Dry Gas 164.019 163.569 166.793 164.794

Meter, corrected to Standard Conditions, dscf Vwcstd Volume of Water Vapor Condensed in the Impingers, 0.87 0.94 1.11 0.97

Corrected to Standard Conditions Vwsgstd Volume of Water Vapor Condensed in the Silica Gel, 1.08 0.99 1.02 1.03

Corrected to Standard Conditions Bws Water Vapor in the Gas Stream, proportion 0.012 0.012 0.013 0.012

by volume Md Molecular Weight of Stack Gas, Dry Basis, lb/lb-mole 28.84 28.84 28.84 28.84 Ms Molecular Weight of Stack Gas, Wet Basis, lb/lb-mole 28.71 28.71 28.70 28.71 Ps Absolute Stack Gas Pressure, in. Hg 29.90 29.90 29.90 29.90 Vs Average Stack Gas Velocity, ft/sec 14.57 12.71 14.08 13.79 Qa Wet Volumetric Stack Gas Flow Rate at Actual 940 820 900 890

Conditions, acf/min Qa Wet Volumetric Stack Gas Flow Rate at Actual 56,100 49,000 54,200 53,100

Conditions, acf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 53,000 47,000 53,000 51,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Stack Gas Flow Rate corrected 880 780 880 850

to Standard Conditions, dscf/min % I Isokinetics, % 99.6 111.1 101.2 104.0SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 17
[Flowrate Calculations]

Run Number
4 5 6 Mean Ts Absolute Roof Temperature, °F 119.8 104.8 99.3 108.0 Ts Absolute Roof Temperature, °R 579.8 564.8 559.3 568.0 Vs Average Roof Gas Velocity, ft/min * 74.90 70.20 85.3 76.8 As Cross Sectional Area of Roof, square feet 8,821.3 8,821.3 8,821.3 8,821.3 Qa Wet Volumetric Roof Gas Flow Rate at Actual 660,720.0 619,260.0 752,460.0 677,480.0

Conditions, acf/min Qa Wet Volumetric Roof Gas Flow Rate at Actual 39,642,922 37,155,316 45,147,413 40,648,550

Conditions, acf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 36,162,000 34,792,000 42,692,000 37,882,000

to Standard Conditions, dscf/hour Qs Dry Volumetric Roof Gas Flow Rate corrected 602,700 579,867 711,533 631,367

to Standard Conditions, dscf/min % I Isokinetics, % (As per EPA Method 14, Section 12.2.1) 118.2 110.0 100.3 109.5

*NOTE: Flow measured by plant anemometer.SUMMARY OF TEST RESULTS

POTLINE 4 DOWNCOMER METHOD 17
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number 4 5 6 Mean
Cs(PM) Concentration of Particulate Matter , grains/dscf 9.13E-04 1.75E-03 1.52E-03 1.39E-03
Cs(PM) Concentration of Particulate Matter, mg/dscm 2.1 4.0 3.5 3.2
Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 6.92E-03 1.17E-02 1.15E-02 1.00E-02

SUMMARY OF TEST RESULTS

POTLINE 4 ROOF MONITOR DUCT

METHOD 315
[Pollutant Calculations]
Century Aluminum of Kentucky, LLC Hawesville, Kentucky

Run Number Total Test Section Emissions Rate 4 5 6 Mean Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 4.72 8.68 9.29 7.56 PR(alum) Production Rate, ton/hour alum. equivalent 1.57 1.57 1.57 1.57 Mp(PM) Total Particulate Matter Emissions Rate,lbs/ton alum. Equivalent 3.01 5.53 5.92 4.82

Run Number Total Line Emissions Rate 4 5 6 Mean Mp(PM) Total Particulate Matter Emissions Rate , lbs/hour 18.88 34.73 37.15 30.25