DEVELOPMENT OF THE MACT FLOORS AND MACT FOR THE FINAL NESHAP 

FOR GOLD MINE ORE PROCESSING AND PRODUCTION

Metals and Minerals Group

Sector Policies and Programs Division

Office of Air Quality Planning and Standards

U.S. Environmental Protection Agency

Research Triangle Park, NC

December 16, 2010
1

Development of the MACT Floors and MACT for the Final NESHAP for Gold Mine Ore 

Processing and Production

1. Selection of Affected Source

The Gold Mine Ore Processing and Production source category consists of facilities 

engaged in processing gold ore to recover gold using roasters, autoclaves, carbon kilns, melt 

furnaces, mercury retorts, electrowinning, and preg tanks. There were approximately 21 gold 

mine ore processing facilities operating these processes in the United States in 2008.

The final rule applies to each new or existing affected source and specifies maximum 

achievable control technology (MACT) standards for mercury emissions for the following four

affected sources in the Gold Mine Ore Processing and Production source category: ore 

pretreatment, carbon processes with mercury retorts, carbon processes without mercury retorts, 

and non-carbon concentrate processes. These affected sources reflect the differences in process 

operations, the sources of mercury entering the processes, and the nature of the emissions.

Ore Pretreatment

The ore pretreatment affected source includes roasting operations and autoclaves that 

pretreat refractory ore, which contains organic carbon and sulfide mineral grains that prevent the 

initial use of cyanide leaching to effectively extract the gold from the ore. The refractory ore is 

oxidized in the roaster or autoclave, converting it to an “oxidized” ore, which can then be 

effectively leached with cyanide solution. Mercury enters these processes with the ore. 

There are four existing facilities that use ore pretreatment processes, and mercury 

emissions data are available for all four of these facilities. The potential for mercury emissions 

from this affected source is directly related to the amount of ore processed in the autoclaves and 

roasters; consequently, the format selected for the standard for this affected source is pounds of 

mercury emissions (lb) per million ton of ore processed (lb/million ton of ore). In the 2007-2009 

timeframe, the ore pretreatment sources accounted for approximately 55 percent of the mercury 

emissions from the source category.

Carbon Processes with Mercury Retorts

 The second affected source is carbon processes with mercury retorts, which includes 

those gold production operations that use carbon to collect (adsorb) the gold and mercury from 

solution and the process units that follow (i.e., carbon kilns, pregnant tanks, electrowinning cells, 

mercury retorts, and melt furnaces). Mercury emissions are subsequently generated by these 
2

process units. The primary intermediate product that is common to all of the facilities with these 

carbon processes with mercury retorts is the gold-bearing concentrate, which is the input to 

mercury retorts. Further, concentrate is closely related to the final product because it contains 

about 60 percent gold, and because of its value, it is carefully weighed and records of the 

quantities are kept. The amount of concentrate input to the mercury retort is also required to be 

reported under the Nevada Division of Environmental Protection (NDEP) program, so we had 

comparable and reliable data from the different gold mine facilities. Consequently, we decided 

that the most appropriate format of the emission limit for the carbon processes with mercury 

retorts is lb/ton of concentrate processed. 

There are approximately 10 facilities with the carbon processes with mercury retorts, and 

we have mercury emissions data for 10 of these facilities. In the 2007-2009 timeframe, the 

carbon processes with mercury retorts sources accounted for approximately 44 percent of the 

mercury emissions from the source category.

Carbon Processes without Mercury Retorts

The third affected source is carbon processes without mercury retorts, which includes 

those gold production operations that use carbon to collect the gold and mercury from solution

without the use of mercury retorts. Several facilities have such low concentrations of mercury in 

their ore that they do not require a mercury retort to remove and recover mercury. In addition, 

the average mercury emissions from these types of facilities that do not have mercury retorts are 

a factor of 10 less than facilities that do have mercury retorts. For these reasons, the final rule 

differentiates between carbon processes with and without mercury retorts.

Mercury emissions are subsequently generated by the process units included in this 

affected source (i.e., carbon kilns, pregnant tanks, electrowinning cells, and melt furnaces). 

Similar to the reasons described previously for carbon processes with mercury retorts, the 

concentrate is the input to the melt furnace for carbon processes without mercury retorts; we 

decided that the most appropriate format of the emission limit for the carbon processes without 

mercury retorts is lb/ton of concentrate processed. 

There are approximately eight facilities with the carbon processes without mercury 

retorts, and we have mercury emissions data for two of these facilities. In the 2007-2009 

timeframe, the carbon processes without mercury retorts sources accounted for approximately 

0.19 percent of the mercury emissions from the source category.
3

Non-Carbon Concentrate Processes

This affected source includes facilities with gold ore processes that do not use carbon or 

ore pre-treatment. These facilities do not have roasters, autoclaves, or carbon kilns and instead 

only use mercury retorts and melt furnaces to recover the gold and liberate mercury from the 

concentrate. The amount of mercury entering these processes and potential mercury emissions 

are directly related to the amount of concentrate processed; consequently, the appropriate format 

for the final standard for this affected source is lb/ton of concentrate processed. There are about 

three gold mine ore processing facilities sources with non-carbon concentrate affected sources, 

and we have mercury emissions data for two of these facilities. In the 2007-2009 timeframe, the 

non-carbon concentrate sources accounted for approximately 0.98 percent of the mercury 

emissions from the source category.

2. Approach for Developing the MACT Floor

Pursuant to Section 112(d) of the Clean Air Act, MACT standards for existing 

affected sources must be at least as stringent as the average emissions limitation achieved by 

sources in the MACT pool; that is, the best performing 12 percent of existing affected sources 

for which the Administrator has data for source categories with 30 or more sources or the best 

performing 5 sources for source categories with fewer than 30 sources. This level of 

minimum stringency is called the MACT floor. For new sources, MACT standards must be at 

least as stringent as the control level achieved in practice by the best controlled similar 

affected source. 

The MACT floor limits for each of the four affected sources were calculated based on 

the performance of the lowest emitting (best performing) sources in each pool of sources with 

available data. We ranked all of the sources for which we had valid data representing current 

performance based on their emissions and identified the lowest emitting of the existing 

affected sources, which resulted in 4 facilities with ore pretreatment processes, 10 facilities 

for those with carbon processes with mercury retorts, 2 facilities for those with carbon 

processes without mercury retorts, and 2 facilities with the non-carbon concentrate processes. 

For new sources, MACT was based on the best performing source for each of the four

affected sources.

The run-by-run data and the details of the statistical calculations for the MACT floor 

analyses are provided in Appendices A through E.
4

2.1 Statistical Approach for Existing Sources 

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 the limits are based are 

expressed in terms of pounds of mercury emitted per unit of mass of input, where millions of 

tons of gold mine ore is the input for the ore pretreatment processes and tons of concentrate is the 

input for the carbon processes with mercury retorts, carbon processes without mercury retorts,

and the non-carbon concentrate processes. 

The emissions data for those best performing affected sources were used to determine the 

final emission limits, 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 (D.C. 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 upper prediction 

limit (UPL) approach, which is defined by the following equation:

T df T UPL = x + t v

where:

UPL = upper prediction limit,

T x = the average total emission rate over the best performing affected sources,

df t = the 99th percentile of the t distribution, and

T v = the total variance for the top performing affected sources.

The degrees of freedom associated with df t is given by:

∑ ∑ ( ) = = = − N

i

M

j ij

i

df n

1 1

1
5

where:

N = number of best performing affected sources (2 to 4 for the four affected sources),

Mi = number of mercury emitting processes at each affected source, and

nij = number of mercury emission test runs for each process unit.

The average total emission rate ( T x ) is calculated from: 

∑=

=

N

i

T Ti x

N

x

1

1

where:

N = the number of top N affected sources (N = 2 to 5),

Ti x = the total emission rate of an entire ith affected source.

To calculate Ti x :

∑=

=

Mi

j

Ti ij x x

1

where: 

Mi = the number of distinct units within the ith affected source (i.e., we count all the distinct 

units in an affected source, so if a process type has two or more units, then each of those 

units must be counted), 

ij x = the unit average for the jth unit within the ith affected source. 

To calculate ij x :

∑=

=

ij n

k

ijk

ij

ij x

n

x

1

1

where:

nij = the number of runs within the jth unit of the ith affected source,

xijk = the observation associated with the kth run within the jth unit and ith affected source. 

The total variance ( T v ) consists of the following two variance components:

T B W v = v + v
6

The first variance component ( B v ) is simply the variance of T x (the average total emission rate 

over all affected sources). Suppose 2 var( ) ij ijk s x = is the variance of an individual run in the jth 

unit and ith affected source, then the variance of the unit average, ij x in the jth unit and ith 

affected source is

ij

ij

ij n

s

x

2

var( ) = .

If all units operate independently, then the unit variances, 2

ij s , will be additive. Therefore, based 

on the assumption of variance additivity, the variance of the total emission rate of the ith affected 

source is 

∑=

=

Mi

j ij

ij

Ti

n

s

x

1

2

var( ) ,

and the variance of the average total emission rate over all affected sources is

∑∑= =

= =

N

i

M

j ij

ij

B T

i

n

s

N

v x

1 1

2

2

1 var( ) .

The second variance component ( Wv ) is the variance of T new x , , the total emission rate 

from new test runs at an affected source in the future to determine compliance. The theoretical

formulation of Wv based on these future runs is:

, , 2 ,

1 1 1

1 var( ) var( ) var( )

M M m

W T new j new jk new

j j k

vx x x = m = =

= = ∑ ∑∑ = ,

where jk new , x refers to the kth run of the jth unit in the new affected source, and M is the number 

of units in the new affected source. Also note that the number of units, M, in the affected source

to be tested in the future is unknown and may vary.

However, the theoretical formulation informs us how to derive an operational

formulation of Wv based on the data available from the runs already completed from the top N

affected sources:
7

2

2

1 11 1 1

1 1 1 var( )

N m M M i i N

W ijk ij

i jk i j

v xs

N m = = = Nm = =

  =   =

  ∑ ∑∑ ∑∑

Substituting into the equation provided for UPL earlier and rearranging yields:

2

1 1

1 11 N Mi

T df ij

i j ij

UPL x t s

N Nn m = =

  = + +  

  ∑∑

The first term of the equation refers to the average total emission rate of the top N affected 

sources. The second term accounts for the expected variability in future measurements due to 

variations resulting from system operation and measurement activities, and this variability 

consists of two components. The first component accounts for the variability of the average 

total emissions of the existing lowest emitting MACT pool sources, and the second component 

accounts for the variability of the average of m new test runs based on the observed variance of 

individual runs within test conditions from the lowest emitting MACT pool sources (the 

second component typically accounts for the major portion of the overall variability). The 

variability factor assumes that variability from the individual best performing sources are 

independent, and thus are additive. This is a reasonable assumption because each individual 

best performing source has certain characteristics, such as material inputs, design and 

operation, etc., that are unique to that process unit. 

2.2 Statistical Approach for New Sources

MACT for new sources is based on the UPL for the best performing source for each of 

the four types of affected sources and is calculated from:

1 df T1 UPL = x + t v

where:

1 x = the average total emission rate of the best performing affected source,

df t = the 99th percentile of the t distribution with (n – 1) degrees of freedom, and

T1 v = the total variance of the best performing source.

The total variance of the best performing source is calculated from the formulas given in Section 

2.1, except that in this case, N = 1 and the subscript i is replaced by the subscript 1:

1

2

1 1

1 1

1 1 M

T j

j j

v s = n m

 

= +  

  ∑ ,
8

where 2

1 j s and 1 j n are the variance and number of runs, respectively, from the jth mercuryemitting unit of the best performing source, M1 is the number of distinct mercury-emitting units 

in this source, and m is the number of future runs to determine compliance (typically 3).

3. MACT Floor for Mercury

Most of the mercury emissions data used in the MACT floor analyses were obtained 

from annual testing that was required by the Nevada Division of Environmental Protection 

(NDEP) for 2007 through 2009.

1

The NDEP invalidated several mercury emission tests conducted in 2007 and 2008 

because of failures to comply with the federal reference test method, failure to comply with

the established testing protocol, possible sample contamination, etc. See docket item EPAHQ-OAR-2010-0239-0061 for a complete list and rationale for invalidated tests. As a result, 

none of the test data for Barrick Goldstrike’s roasters and autoclaves for 2008 were used in 

the analysis. However, 2007 and 2009 data for Goldstrike’s autoclaves and roasters were

used in the analyses. The 2007 and 2008 tests for the mercury retorts at Goldstrike were also 

invalidated; however, test data for 2009 were available for the mercury retorts and were used 

in the analysis for the carbon processes with mercury retorts. Other tests that were invalidated 

included the 2007 tests at Coeur Rochester, one of the October 2008 tests at Marigold, two of 

the August 2007 ore preheater tests at Goldstrike, and one of the February 2010 roaster tests 

at Jerritt Canyon. In addition, we excluded data from the October 2009 emission test on one 

of the melt furnaces for the Cortez Pipeline facility. The NDEP reported that, for that test, the 

 However, 2010 test data were used for one facility that 

installed new mercury emission controls on its roasters and resumed operation in late 2009. 

The tests generally consist of three runs per test per process at each affected source. Most of 

the measurements were made using EPA Method 29; however, Method 101A and the Ontario 

Hydro method were used in a few cases. There were cases where 2007 and/or 2008 results 

represent emissions before a control device was installed, and 2008 and/or 2009 test results 

represent emissions after a mercury emission control device had been installed. In those 

cases, we used only the controlled test results to determine the top performing affected 

sources. Emissions in lb/hr were multiplied by the number of hours the process operated in 

2007, 2008, or 2009 and then divided by the process input rate for the year (in tons or million 

tons) to express mercury emissions in lbs per ton (or million tons) of input material.

 

1 A complete listing of the emission test data is provided in Appendix A through F of this document.
9

mercury content of the concentrate was only 8 ppm, whereas the content for the December 

2009 test was 1,557 ppm, and the content in 2007 and 2008 averaged 4,480 ppm and 4,250

ppm, respectively. Based on that information, we concluded that the mercury content was 

unusually low for the October test, and the emissions data would not be representative of 

typical operations.

The following paragraphs discuss the results of the MACT floor analyses for the four 

affected sources for the Gold Mine Ore Processing and Production source category. Tables 1

through 4 summarize the results. 

Ore Pretreatment

Valid emissions data were available for all four of the facilities with ore pretreatment 

processes. As shown in Table 1, the average emissions level achieved by these four facilities 

is 84 lb Hg/million tons of ore. The MACT floor based on the UPL is 158 lb Hg/million tons 

of ore. For new sources, MACT corresponds to 84 lb Hg/million tons of ore. We estimate 

that requiring the MACT floor emission limit for this affected source would reduce emissions 

of mercury by about 431 pounds per year (lbs/yr), a reduction of 30 percent from current 

levels. In addition, energy consumption would increase by about 11,400 megawatt-hours per 

year (or 11.4 gigawatt-hours per year). Solid waste generation and disposal (spent carbon 

loaded with mercury) would increase by about 3 tons per year.

Table 1. MACT Floor Results for Ore Pretreatment

Affected Source Average performance (lb Hg/million tons ore)

Goldstrike (Facility A) 45 (14 tests, 42 runs)

Gold Quarry (Facility C) 56 (17 tests, 51 runs)

Jerritt Canyon Mine (Facility E) 71 (7 tests, 21 runs)

Twin Creeks Mine (Facility D) 165 (12 tests, 36 runs)

Summary of Statistical Analysis

Statistic Existing (top 4) New

Average (lb/MM tons) 84 45

df 131 42

t 2.36 2.42

Vb 52 65

Vw 935 198

Vt 988 263

99% UPL (lb/MM tons), MACT Floor 158 84
10

Carbon Processes with Mercury Retorts

Valid emissions data were available for 10 facilities that operate carbon processes with 

mercury retorts. Based on the MACT floor analysis, the average emissions level achieved by 

the best performing five sources is 1.1 lb Hg/ton of concentrate. After accounting for the 

variability in emissions, the MACT floor for this affected source is 2.2 lb Hg/ton of 

concentrate. For new sources, MACT is 0.8 lb Hg/ton concentrate. We estimate that the 

MACT floor limit for this affected source would reduce emissions by about 899 lbs/yr, a 

reduction of 78 percent from current levels.

Table 2. MACT Floor Results for Carbon Processes with Mercury Retorts

Affected Source Average performance (lb Hg/ton concentrate)

Marigold (Facility N) 0.53 (7 tests, 21 runs)

Bald Mountain (Facility J) 0.74 (4 tests, 12 runs)

Ruby Hill (Facility I) 1.06 (4 tests, 11 runs)

Goldstrike (Facility A) 1.47 (18 tests, 54 runs)

Denton-Rawhide (Facility H) 1.67 (12 tests, 36 runs)

Twin Creeks (Facility D) 2.20 (31 tests, 93 runs)

Gold Quarry (Facility C) 3.71 (21 tests, 57 runs)

Florida Canyon (Facility G) 8.17 (18 tests, 54 runs)

Jerritt Canyon (Facility E) 14.49 (2 tests, 6 runs)

Lone Tree (Facility B) 20.60 (7 tests, 21 runs)

Summary of Statistical Analysis

Statistic Existing (top 5) New

Average (lb/tons) 1.1 0.53

Df 110 17

t 2.36 2.57

Vb 0.015 0.0032

Vw 0.20 0.0037

Vt 0.22 0.0069

99% UPL (lb/ton), MACT Floor 2.2 0.8

Carbon Processes without Mercury Retorts

Valid data were available for two facilities that operate carbon processes without 

mercury retorts. As shown in Table 3, the average emissions level achieved by these two

facilities is 0.078 lb Hg/ton of concentrate. The existing MACT floor based on the UPL is 
11

0.17 lb Hg/ton of concentrate. For new sources, MACT corresponds to 0.14 lb Hg/ton of 

concentrate.

Table 3. MACT Floor Results for Carbon Processes without Mercury Retorts

Affected Source Average performance (lb Hg/ton concentrate)

Round Mountain (Facility M) 0.058 (5 tests, 15 runs)

Cortez (Facility F) 0.098 (13 tests, 39 runs)

Summary of Statistical Analysis

Statistic Existing (top 2) New

Average (lb/ton) 0.078 0.058

df 43 12

t 2.42 2.68

Vb 0.00031 0.00045

Vw 0.0010 0.00048

Vt 0.0013 0.00093

99% UPL (lb/ton), MACT Floor 0.17 0.14

Non-Carbon Concentrate Processes

For this affected source, valid emissions data were available for two facilities. The 

results of the analysis are summarized in Table 4. Based on the MACT floor analysis, the 

average emissions level achieved by these two facilities is 0.062 lb Hg/ton of concentrate. 

The MACT floor for this affected source is 0.2 Hg/ton of concentrate. For new sources, 

MACT is 0.1 lb Hg/ton concentrate. We estimate that requiring the MACT floor emissions 

limit for non-carbon concentrate processes would reduce emissions by about 14 lbs/yr, a 

reduction of 54 percent from current levels.

Table 4. MACT Floor Results for Non-Carbon Concentrate Processes

Affected Source Average performance (lb Hg/ton concentrate)

Coeur Rochester Mine (Facility K) 0.047 (5 tests, 17 runs)

Midas Operations (Facility L) 0.078 (13 tests, 27 runs)

Summary of Statistical Analysis

Statistic Existing (top 2) New

Average (lb/ton) 0.062 0.047

df 39 15

t 2.43 2.60

Vb 0.00024 0.00026

Vw 0.0026 0.00052

Vt 0.0028 0.00077

99% UPL (lb/ton), MACT Floor 0.2 0.1
12

4. Beyond the Floor2

To evaluate opportunities for emission reductions beyond those that would result from 

requiring facilities to meet the MACT floor emissions limits, we typically identify control 

techniques that have the ability to achieve an emissions limit more stringent than the MACT 

floor. The following paragraphs summarize the results of this "beyond-the-floor" analysis for 

the four affected sources for the Gold Mine Ore Processing and Production source category.

 

Ore Pretreatment

Facilities with ore pretreatment processes have installed, or would need to install, 

calomel mercury scrubbers on their roasters and venturi scrubbers and/ maybe carbon 

adsorbers on their autoclaves, to achieve the MACT floor for ore pretreatment processes. To 

achieve further reduction in mercury, one beyond-the-floor option is the installation of both a 

refrigeration unit and a carbon adsorber on the facilities with autoclaves. This additional 

control system would follow the existing venturi scrubbers, and, because autoclave exhaust is 

saturated with water, a refrigeration unit or condenser would be required to remove moisture

that would otherwise adversely affect the adsorptive capacity of the carbon adsorber. We 

assumed that the additional control from the carbon adsorber would result in a 70 percent 

reduction of mercury emissions. This value was proposed by Newmont Twin Creeks facility 

in their Phase 2 application to the Nevada Mercury Control Program. We believe that it is an 

appropriate estimate of emissions reductions seeing as this control has never been 

demonstrated on an autoclave. 

The estimated capital cost for the additional controls for the autoclaves at Twin Creeks 

would be $29.3 million, with a total annualized cost of $4.9 million/yr. Based on an 

estimated control efficiency of 70 percent, mercury emissions would be reduced by 431 

lbs/yr, resulting in an estimated cost effectiveness of $11,390/lb. We are incorporating this 

beyond-the-floor analysis in the final rule.

We estimate the capital cost for the additional controls on the autoclaves at Goldstrike 

would be $47,000,000, with a total annualized cost of $8,200,000/yr. This option would

reduce mercury emissions by 10 lbs/yr, resulting in an estimated cost effectiveness of 

 

2 Additional details and documentation for the estimates of emissions, emission reductions, and costs are provided 

in the rulemaking docket (EPA-HQ-OAR-2010-0239).
13

$782,409/lb. Because of the high cost effectiveness for addition controls to the autoclaves at 

Goldstrike, we are not incorporating this beyond-the-floor analysis in the final rule.

We also identified as a beyond-the-floor option the installation of a carbon adsorber on 

ore preheater/dryer units. Again, we assumed that the additional control from the carbon 

adsorber would result in a 70 percent reduction of mercury emissions on the ore 

preheater/dryer units. We believe that this is an appropriate estimate of emissions reductions 

because this control has never been demonstrated on these units. We estimated the capital 

cost for the additional controls as $2,962,000, with a total annualized cost of $1,622,000/yr. 

Based on an estimated control efficiency of 70 percent, mercury emissions would be reduced 

by 118 lbs/yr, resulting in an estimated cost effectiveness of $13,784/lb. 

Another assumption used in the beyond-the-floor calculations was that one facility, 

which has both roasters and autoclaves, would operate only their roasters. With these

additional controls, the average emissions level achieved by these sources facilities would be 

80 lb/million tons of ore. We estimate that requiring the MACT floor emissions limit and the 

beyond-the-floor options for ore pretreatment processes results in a total emissions reductions 

of 548 lbs/yr, a reduction of 38 percent from current levels. Applying the UPL formula to 

account for variability, the resulting beyond-the-floor emissions limit would be 127 lb/million 

tons of ore. Table 5 summarizes the beyond-the-floor analysis for ore pretreatment processes. 

This emission limit was incorporated in the final rule. 

We also evaluated a beyond-the-floor option for the new source standard. The best 

performing similar source for the ore pretreatment affected source is the Goldstrike facility. 

We identified as a beyond-the-floor option the installation of a carbon adsorber on the 

autoclaves and on ore preheater units at this facility. We estimated the capital cost for the 

additional controls as $48,100,000, with a total annualized cost of $9,419,000/yr. Based on 

an estimated control efficiency of 70 percent for the controls on the autoclaves and the ore 

preheaters, mercury emissions would be reduced by 44.6 lbs/yr, resulting in an estimated cost 

effectiveness of $211,188/lb. Because of the high cost effectiveness values, the beyond-thefloor anyslsysis for new sources in the ore pretreatment affected source were not adopted in 

the final rule.
14

Table 5. Beyond the Floor Results for Ore Pretreatment

Affected Source

Average performance 

(lb Hg/million tons ore)

Gold Quarry (Facility C) (70% reduction) 37

Twin Creeks (Facility D) (70% reduction) 49

Jerritt Canyon (Facility E) (70% reduction) 58

Goldstrike (Facility A) (70% reduction) 80

Summary of Statistical Analysis

Statistic

Average achieved by all (lb/MM tons) 80

df 123

t 2.36

Vb 30

Vw 369

Vt 399

Affected Source 99% UPL (lb/MM tons) 127

Other Affected Sources

For two of the other affected sources (carbon processes with mercury retorts and noncarbon concentrate processes), existing sources are equipped with efficient mercury emission 

controls, and it is difficult to identify a technology that might be applied to achieve further 

reductions in emissions, especially considering the very low mercury concentrations after the 

MACT floor level of control and the difficulty in obtaining efficient additional percent 

reductions for low concentration streams. For the beyond-the-floor analysis, we assumed that 

a second carbon adsorption system could be installed in series with the first or existing 

adsorber and would get an additional reduction of 90 percent. (We acknowledge that there is 

significant uncertainty in the additional reductions the redundant control system might 

achieve.) For carbon processes with mercury retorts, the capital cost for the additional control 

was estimated to be $3 million, with a total annualized cost of $1.3 million/yr. The emissions

reductions for this control option would be 9 lbs/yr, resulting in an estimated cost 

effectiveness of $150,275/lb. For non-carbon concentrate processes, we estimated the capital 

cost for the additional adsorber to be $0.4 million, with a total annualized cost of 

$191,000/year. The mercury emissions reductions that would be achieved by this option 

would be 0.13 lb/year, resulting in an estimated cost effectiveness of $1,400,000/lb. Because 

of the uncertainties in the emissions reductions that could be achieved, and the high cost 

effectiveness values, beyond-the-floor limits for these three types of affected sources were not 
15

adopted in the final rule.

For a beyond-the-floor analysis for carbon processes without mercury retorts, we 

estimated the costs and reductions for installing a carbon adsorber to a unit at Round 

Mountain that is currently uncontrolled. The capital cost for a carbon adsorber was estimated 

to be $0.2 million with a total annualized cost of $72,000/yr. The mercury emissions

reduction associated with this option would be 1.6 lbs/yr, resulting in an estimated cost 

effectiveness of $44,000/lb. We do not believe that the small emission reduction that this 

control option would achieve is justified in light of its cost. We therefore decided not to go 

beyond-the-floor.

4. Summary of Final Emission Standards 

Table 6 summarizes the mercury emission limits included in the final Gold Mine Ore 

Processing and Production Area Source NESHAP. 

Table 6. Summary of Final Mercury Emission Limits

Affected Source

Hg Emission Limits

Existing Units

Sources

New 

Sources

Ore pretreatment processes 127 84 lb/million tons of ore

Carbon processes with mercury retorts 2.2 0.8 lb/ton of concentrate

Carbon processes without mercury retorts 0.17 0.14 lb/ton of concentrate

Non-carbon concentrate processes 0.2 0.1 lb/ton of concentrate
16

Appendix A. Mercury Emissions Data for the Ore Pretreatment Affected Source (lb/ton of ore)

Facility Unit 

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs per 

unit

DF (n-1) 

per unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 

3 per 

unit)

Facility 

Vw

Gold Quarry

Roaster/Calcine 

quench 1.35E-05 9.56E-06 1.37E-05

Gold Quarry

Roaster/Calcine 

quench 1.05E-05 1.33E-05 1.69E-05

Gold Quarry

Roaster/Calcine 

quench 8.45E-06 1.05E-05 9.66E-06 1.06E-04 1.18E-05 7.33E-12 9 8 8.14E-13 2.44E-12

Gold Quarry

Roaster Ore 

Preheater 1.27E-05 5.41E-06 4.53E-06

Gold Quarry

Roaster Ore 

Preheater 2.63E-05 2.50E-05 1.54E-04

Gold Quarry

Roaster Ore 

Preheater 8.18E-06 3.48E-06 3.03E-06 2.43E-04 2.70E-05 2.35E-09 9 8 2.62E-10 7.85E-10

Gold Quarry Roaster 8.99E-07 6.97E-07 7.87E-07

Gold Quarry Roaster 1.27E-06 1.61E-06 6.19E-07

Gold Quarry Roaster 4.92E-07 2.75E-07 3.56E-07 7.00E-06 7.78E-07 1.86E-13 9 8 2.07E-14 6.21E-14

Gold Quarry

Roaster Ore 

Grinder 1.66E-06 2.06E-06 1.48E-06

Gold Quarry

Roaster Ore 

Grinder 1.50E-06 4.82E-06 1.75E-06 1.33E-05 2.21E-06 1.67E-12 6 5 2.79E-13 5.58E-13

Gold Quarry

Roaster/Calcine 

quench 1.67E-05 1.36E-05 9.55E-06

Gold Quarry

Roaster/Calcine 

quench 1.27E-05 1.46E-05 2.11E-05

Gold Quarry

Roaster/Calcine 

quench 1.03E-05 1.31E-05 1.32E-05 1.25E-04 1.39E-05 5.56E-05 1.19E-11 9 8 1.32E-12 2.64E-10 3.96E-12 7.92E-10

Goldstrike

Roaster Ore 

Preheater 3.23E-07 5.03E-07 3.60E-07

Goldstrike

Roaster Ore 

Preheater 8.61E-07 5.96E-07 5.17E-07

Goldstrike

Roaster Ore 

Preheater 1.79E-06 1.39E-06 2.65E-07

Goldstrike

Roaster Ore 

Preheater 2.19E-06 1.13E-06 2.65E-07 1.02E-05 8.48E-07 4.12E-13 12 11 3.43E-14 1.37E-13

Goldstrike

Roaster Ore 

Preheater 8.68E-06 4.71E-06 1.71E-06

Goldstrike

Roaster Ore 

Preheater 2.36E-05 5.05E-06 7.86E-07

Goldstrike

Roaster Ore 

Preheater 8.52E-07 8.52E-07 3.93E-07

Goldstrike

Roaster Ore 

Preheater 1.64E-06 8.52E-07 3.93E-07 4.95E-05 4.12E-06 4.40E-11 12 11 3.67E-12 1.47E-11
17

Facility Unit 

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs per 

unit

DF (n-1) 

per unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 

3 per 

unit)

Facility 

Vw

Goldstrike Roaster 7.25E-05 5.71E-05 5.26E-05

Goldstrike Roaster 1.25E-05 1.25E-05 1.71E-05

Goldstrike Roaster 1.95E-05 1.73E-05 1.31E-05 2.74E-04 3.05E-05 5.47E-10 9 8 6.08E-11 1.82E-10

Goldstrike

Roaster/Calcine 

quench 4.35E-06 2.96E-06 2.87E-06 1.02E-05 3.39E-06 6.86E-13 3 2 2.29E-13 2.29E-13

Goldstrike

Roaster/Calcine 

quench 3.55E-06 3.76E-06 3.32E-06 1.06E-05 3.54E-06 4.72E-14 3 2 1.57E-14 1.57E-14

Goldstrike Autoclave 2.59E-07 4.01E-07 4.70E-07 1.13E-06 3.77E-07 1.16E-14 3 2 3.87E-15 3.87E-15

Goldstrike Autoclave 6.57E-07 7.71E-07 5.50E-07 1.98E-06 6.59E-07 1.23E-14 3 2 4.09E-15 4.09E-15

Goldstrike Autoclave 1.42E-06 1.65E-07 1.81E-07 1.77E-06 5.90E-07 5.21E-13 3 2 1.74E-13 1.74E-13

Goldstrike Autoclave 1.42E-06 8.32E-07 4.62E-07 2.71E-06 9.03E-07 4.49E-05 2.32E-13 3 2 7.72E-14 6.50E-11 7.72E-14 1.98E-10

Jerritt 

Canyon Ore dryer 1.35E-05 2.86E-05 1.92E-05

Jerritt 

Canyon Ore dryer 3.82E-06 3.24E-05 1.14E-05 1.09E-04 1.82E-05 1.17E-10 6 5 1.95E-11 3.90E-11

Jerritt 

Canyon Roaster 4.42E-05 4.47E-05 5.14E-05

Jerritt 

Canyon Roaster 4.48E-05 2.07E-05 2.99E-05

Jerritt 

Canyon Roaster 7.01E-06 7.92E-06 8.36E-06 2.59E-04 2.88E-05 3.31E-10 9 8 3.68E-11 1.10E-10

Jerritt 

Canyon Roaster 5.50E-05 4.65E-05 2.82E-05

Jerritt 

Canyon Roaster 5.80E-06 4.30E-06 4.65E-06 1.44E-04 2.41E-05 7.10E-05 5.16E-10 6 5 8.60E-11 1.42E-10 1.72E-10 3.21E-10

Twin Creeks Autoclave 5.52E-05 1.45E-04 1.02E-04

Twin Creeks Autoclave 7.82E-05 2.59E-04 2.90E-05

Twin Creeks Autoclave 2.36E-04 1.17E-04 1.08E-04

Twin Creeks Autoclave 2.13E-04 1.33E-04 1.10E-04

Twin Creeks Autoclave 9.97E-05 1.97E-04 2.66E-04

Twin Creeks Autoclave 1.06E-04 6.95E-05 6.21E-05

Twin Creeks Autoclave 8.65E-06 8.07E-06 7.63E-06 2.41E-03 1.15E-04 6.39E-09 21 20 3.04E-10 2.13E-09

Twin Creeks Autoclave 1.14E-04 5.47E-05 5.33E-05

Twin Creeks Autoclave 8.67E-05 4.98E-05 3.45E-05

Twin Creeks Autoclave 4.87E-05 9.07E-05 7.96E-05

Twin Creeks Autoclave 3.53E-05 2.50E-05 2.12E-05

Twin Creeks Autoclave 2.04E-05 1.91E-05 1.96E-05 7.53E-04 5.02E-05 1.65E-04 9.06E-10 15 14 6.04E-11 3.65E-10 3.02E-10 2.43E-09

Average 

of top 4: 8.41E-05 t DF: 131 Vb: 5.22E-11

Vw 

(unpoole

d): 9.35E-10

t(.99): 2.36
18

Appendix B. Mercury Emissions Data for the Carbon Processes with Mercury Retorts Affected Source (lb/ton concentrate)

Facility Unit

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs 

per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 3 

per unit)

Facility 

Vw

Marigold EW, P/B 3.68E-01 5.43E-01 4.32E-01 1.34E+00 4.48E-01 7.86E-03 3 2 2.62E-03 2.62E-03

Marigold Retort 7.72E-02 1.14E-01 9.07E-02

Marigold Retort 2.48E-03 1.14E-02 1.37E-03 2.97E-01 4.95E-02 2.52E-03 6 5 4.20E-04 8.41E-04

Marigold Furnace 8.49E-02 4.11E-02 2.52E-02

Marigold Melt Furnace 1.00E-02 1.09E-02 1.74E-02 1.90E-01 3.16E-02 8.13E-04 6 5 1.36E-04 2.71E-04

Marigold Carbon Kiln 7.52E-03 6.29E-03 6.99E-03

Marigold Carbon Kiln 7.36E-04 2.45E-04 3.93E-04 2.22E-02 3.69E-03 5.33E-01 1.27E-05 6 5 2.12E-06 3.18E-03 4.25E-06 3.74E-03

Bald 

Mountain Carbon Kiln 2.37E-02 1.61E-02 1.82E-02 5.80E-02 1.93E-02 1.55E-05 3 2 5.17E-06 5.17E-06

Bald 

Mountain

EW, Barren 

Tank 7.41E-01 1.76E-01 1.08E+00 2.00E+00 6.66E-01 2.10E-01 3 2 6.99E-02 6.99E-02

Bald 

Mountain Melt Furnace 7.09E-02 3.63E-02 4.76E-02 1.55E-01 5.16E-02 3.11E-04 3 2 1.04E-04 1.04E-04

Bald 

Mountain Retort 1.11E-03 1.09E-03 4.79E-04 2.68E-03 8.94E-04 7.38E-01 1.30E-07 3 2 4.32E-08 7.00E-02 4.32E-08 7.00E-02

Ruby Hill Carbon Kiln 2.30E-01 2.16E-01 8.08E-02 5.26E-01 1.75E-01 6.77E-03 3 2 2.26E-03 2.26E-03

Ruby Hill EW, P/B 1.51E+00 5.45E-01 4.97E-01 2.55E+00 8.49E-01 3.24E-01 3 2 1.08E-01 1.08E-01

Ruby Hill Melt Furnace 3.02E-02 3.63E-02 6.65E-02 3.33E-02 1.83E-05 2 1 9.13E-06 6.09E-06

Ruby Hill Retort 1.30E-04 1.30E-04 1.14E-04 3.73E-04 1.24E-04 1.06E+00 8.79E-11 3 2 2.93E-11 1.10E-01 2.93E-11 1.10E-01

Goldstrike Carbon Kiln 5.45E+00 9.68E-01 5.60E-01

Goldstrike Carbon Kiln 4.27E-01 6.21E-01 4.20E-01

Goldstrike Carbon Kiln 1.28E+00 1.31E+00 1.57E+00

Goldstrike Carbon Kiln 1.40E+00 1.46E+00 1.35E+00

Goldstrike Carbon Kiln 6.41E-01 9.07E-01 4.05E-01

Goldstrike Carbon Kiln 2.39E-02 3.23E-02 3.77E-02 1.89E+01 1.05E+00 1.47E+00 18 17 8.18E-02 4.91E-01

Goldstrike Electrowinning 1.58E-01 1.80E-01 2.02E-01

Goldstrike Electrowinning 2.74E-01 3.93E-01 2.25E-01

Goldstrike Electrowinning 1.06E-01 7.07E-02 1.63E-01 1.77E+00 1.97E-01 9.04E-03 9 8 1.00E-03 3.01E-03

Goldstrike Melt Furnace 2.93E-02 7.35E-02 2.35E-02

Goldstrike Melt Furnace

Goldstrike Melt Furnace 4.56E-02 1.28E-01 2.10E-01 5.10E-01 8.50E-02 5.21E-03 6 5 8.68E-04 1.74E-03

Goldstrike Preg Tank 2.07E-02 1.43E-02 7.33E-03

Goldstrike Preg Tank 2.78E-03 3.18E-03 4.04E-03 5.23E-02 8.72E-03 5.28E-05 6 5 8.79E-06 1.76E-05

Goldstrike Preg Tank 3.97E-03 1.33E-02 1.19E-02

Goldstrike Preg Tank 3.18E-03 1.99E-03 2.19E-03 3.66E-02 6.10E-03 2.63E-05 6 5 4.39E-06 8.77E-06

Goldstrike Retort

Goldstrike Retort

Goldstrike Retort
19

Facility Unit

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs 

per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 3 

per unit)

Facility 

Vw

Goldstrike Retort

Goldstrike Retort 5.91E-02 4.77E-02 3.29E-02 1.40E-01 4.65E-02 1.73E-04 3 2 5.76E-05 5.76E-05

Goldstrike Retort

Goldstrike Retort

Goldstrike Retort

Goldstrike Retort 3.00E-02 1.52E-02 1.23E-02 5.75E-02 1.92E-02 8.94E-05 3 2 2.98E-05 2.98E-05

Goldstrike Retort

Goldstrike Retort

Goldstrike Retort

Goldstrike Retort

Goldstrike Retort 5.85E-02 6.70E-02 6.34E-02 1.89E-01 6.29E-02 1.47E+00 1.84E-05 3 2 6.13E-06 8.38E-02 6.13E-06 4.95E-01

DentonRawhide Carbon Kiln 3.16E-03 3.47E-03 1.66E-02

DentonRawhide Carbon Kiln 1.15E-02 6.48E-03 2.07E-03

DentonRawhide Carbon Kiln 2.50E-01 1.45E-01 1.28E-01 5.67E-01 6.30E-02 8.10E-03 9 8 9.00E-04 2.70E-03

DentonRawhide Electrowinning 6.46E-04 2.43E-04 6.39E-03

DentonRawhide Electrowinning 1.40E-02 2.62E-03 3.25E-03

DentonRawhide Electrowinning 9.14E-03 6.49E-02 1.27E-01 2.29E-01 2.54E-02 1.87E-03 9 8 2.08E-04 6.24E-04

DentonRawhide Melt Furnace 3.64E+00 1.56E+00 1.19E+00

DentonRawhide Melt Furnace 8.90E-01 1.85E+00 1.48E+00

DentonRawhide Melt Furnace 7.84E-01 2.34E+00 3.23E-01 1.41E+01 1.56E+00 9.69E-01 9 8 1.08E-01 3.23E-01

DentonRawhide Retort 5.84E-05 6.33E-05 7.17E-05

DentonRawhide Retort 4.59E-05 1.50E-05 1.40E-05

DentonRawhide Retort 6.24E-02 4.38E-02 7.62E-02 1.83E-01 2.03E-02 1.67E+00 9.89E-04 9 8 1.10E-04 1.09E-01 3.30E-04 3.27E-01

Average of 

top 5: 1.09E+00 tDF: 110 Vb: 1.50E-02

Vw 

(unpooled): 2.01E-01

t(.99): 2.36

Twin Creeks Electrowinning 2.29E-02 1.21E-01 4.91E-01

Twin Creeks Electrowinning 1.74E+00 1.06E+00 1.18E+00

Twin Creeks Electrowinning 6.73E-02 4.31E-02 3.46E-02 4.75E+00 5.28E-01 4.10E-01 9 8 4.55E-02 1.37E-01
20

Facility Unit

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs 

per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 3 

per unit)

Facility 

Vw

Twin Creeks

Melt Furnace 2 

(new) 4.20E-01 1.20E-01 2.89E-01

Twin Creeks

Melt Furnace 2 

(new) 4.85E-01 1.38E-01 3.90E-01

Twin Creeks

Melt Furnace 2 

(new) 6.60E-02 1.86E-02 4.80E-02

Twin Creeks

Melt Furnace 2 

(new) 1.77E-04 2.48E-04 6.84E-04 1.98E+00 1.65E-01 3.29E-02 12 11 2.74E-03 1.10E-02

Twin Creeks

Melt Furnace 1 

(old) 1.04E+00 4.20E-01 6.54E-01

Twin Creeks

Melt Furnace 1 

(old) 2.19E+00 8.51E-01 9.32E-01

Twin Creeks

Melt Furnace 1 

(old) 2.15E-02 6.39E-02 9.35E-02

Twin Creeks

Melt Furnace 1 

(old) 7.79E-02 4.07E-02 2.67E-02

Twin Creeks

Melt Furnace 1 

(old) 5.36E-04 4.56E-04 4.88E-04 6.42E+00 4.28E-01 3.84E-01 15 14 2.56E-02 1.28E-01

Twin Creeks Carbon Kiln 2.19E-01 2.30E-02 9.55E-02

Twin Creeks Carbon Kiln 2.80E-01 1.07E-01 9.08E-02

Twin Creeks Carbon Kiln 4.76E-02 8.89E-02 8.76E-02 1.04E+00 1.16E-01 6.70E-03 9 8 7.44E-04 2.23E-03

Twin Creeks Preg Tank 2.12E+00 1.91E+00 3.64E-01

Twin Creeks Preg Tank 8.16E-01 1.74E+00 7.75E-01

Twin Creeks Preg Tank 2.57E-01 2.58E-01 3.22E-01 8.56E+00 9.52E-01 5.83E-01 9 8 6.48E-02 1.94E-01

Twin Creeks Retort 8.80E-06 7.63E-06 6.72E-06 2.32E-05 7.72E-06 1.09E-12 3 2 3.63E-13 3.63E-13

Twin Creeks Retort 8.13E-04 1.19E-03 2.39E-03

Twin Creeks Retort 4.18E-03 4.99E-03 1.04E-02

Twin Creeks Retort 2.57E-03 6.68E-04 1.08E-03 2.82E-02 3.14E-03 9.63E-06 9 8 1.07E-06 3.21E-06

Twin Creeks Retort 3.51E-04 1.34E-03 1.38E-03

Twin Creeks Retort 1.56E-03 5.66E-03 2.78E-03

Twin Creeks Retort 5.07E-04 2.54E-03 5.07E-04 1.66E-02 1.85E-03 2.79E-06 9 8 3.10E-07 9.29E-07

Twin Creeks Retort 7.58E-04 2.96E-03 5.40E-03

Twin Creeks Retort 7.54E-05 2.46E-04 3.09E-04

Twin Creeks Retort 4.75E-04 3.43E-03 4.05E-03 1.77E-02 1.97E-03 4.03E-06 9 8 4.48E-07 1.34E-06

Twin Creeks Retort 2.17E-05 5.49E-03 2.06E-03

Twin Creeks Retort 6.50E-04 4.77E-04 1.73E-04

Twin Creeks Retort 1.17E-04 2.75E-04 4.95E-04 9.77E-03 1.09E-03 2.20E+00 3.11E-06 9 8 3.45E-07 1.39E-01 1.04E-06 4.72E-01

Gold Quarry Carbon Kiln 3.46E+00 3.60E+00 3.93E+00

Gold Quarry Carbon Kiln 7.47E-01 3.88E-01 5.59E-01

Gold Quarry Carbon Kiln 1.29E+00 1.21E+00 1.41E+00 1.66E+01 1.84E+00 1.99E+00 9 8 2.21E-01 6.63E-01

Gold Quarry Electrowinning 4.54E-02 4.24E-02 4.64E-02
21

Facility Unit

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs 

per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 3 

per unit)

Facility 

Vw

Gold Quarry Electrowinning 7.32E-02 6.70E-02 5.94E-02

Gold Quarry Electrowinning 4.48E-01 4.25E-01 8.46E-02 1.29E+00 1.44E-01 2.78E-02 9 8 3.09E-03 9.28E-03

Gold Quarry Preg Tank 2.30E-01 2.44E-01 3.71E-01

Gold Quarry Preg Tank 3.36E-01 6.10E-02 1.29E+00

Gold Quarry Preg Tank 3.82E-03 2.38E-01 5.42E-01

Gold Quarry Preg Tank 3.06E-01 3.71E-02 9.78E-02 3.76E+00 3.13E-01 1.19E-01 12 11 9.91E-03 3.96E-02

Gold Quarry Melt Furnace 2.35E+00 5.33E-01 1.25E+00

Gold Quarry Melt Furnace 2.59E-02 6.61E-03 1.81E-01

Gold Quarry Melt Furnace 4.76E-01 1.05E+00 2.90E+00 8.77E+00 9.75E-01 1.07E+00 9 8 1.19E-01 3.58E-01

Gold Quarry Retort

Gold Quarry Retort 3.73E-02 8.17E-02 4.26E-02

Gold Quarry Retort 1.30E-01 9.79E-02 8.90E-02

Gold Quarry Retort 1.67E-01 1.80E-01 1.32E-01

Gold Quarry Retort 1.66E-01 1.72E-01 9.52E-02 9.11E-01 1.52E-01 1.04E-03 6 5 1.74E-04 3.48E-04

Gold Quarry Carbon Kiln 9.23E-01 5.95E-01 4.94E-01

Gold Quarry Carbon Kiln 5.56E-02 6.25E-02 7.94E-02

Gold Quarry Carbon Kiln 1.42E-01 1.41E-01 1.72E-01

Gold Quarry Carbon Kiln 1.60E-01 3.19E-01 2.96E-01 3.44E+00 2.87E-01 3.71E+00 6.93E-02 12 11 5.77E-03 3.59E-01 2.31E-02 1.09E+00

Florida 

Canyon Carbon Kiln 1.03E+00 5.52E-01 6.71E-01

Florida 

Canyon Carbon Kiln 1.30E+01 2.03E+01 2.00E+01

Florida 

Canyon Carbon Kiln 3.87E+00 4.24E+00 1.78E+01

Florida 

Canyon Carbon Kiln 3.23E+00 1.51E+00 3.83E+00 9.00E+01 7.50E+00 6.22E+01 12 11 5.18E+00 2.07E+01

Florida 

Canyon Melt Furnace 3.17E-01 8.30E-03 1.71E-02

Florida 

Canyon Melt Furnace 1.45E-02 2.01E-02 5.11E-02

Florida 

Canyon Melt Furnace 5.76E-03 8.07E-03 9.51E-03 4.52E-01 5.02E-02 1.02E-02 9 8 1.13E-03 3.40E-03

Florida 

Canyon Electrowinning 2.68E-01 1.42E-01 6.00E-01

Florida 

Canyon Electrowinning 1.03E+00 1.47E-01 8.14E-01

Florida 

Canyon Electrowinning 1.38E-01 6.95E-01 1.09E+00 4.92E+00 5.47E-01 1.49E-01 9 8 1.66E-02 4.97E-02

Florida 

Canyon Electrowinning 1.03E-01 1.03E-01 7.10E-02

Florida 

Canyon Electrowinning 7.60E-02 3.41E-02 4.57E-02
22

Facility Unit

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs 

per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 3 

per unit)

Facility 

Vw

Florida 

Canyon Electrowinning 7.72E-02 7.72E-02 1.70E-02 6.03E-01 6.70E-02 8.59E-04 9 8 9.55E-05 2.86E-04

Florida 

Canyon Retort 2.63E-03 1.25E-03 2.90E-04

Florida 

Canyon Retort 2.30E-06 1.53E-06 1.67E-06 4.17E-03 6.95E-04 1.13E-06 6 5 1.88E-07 3.76E-07

Florida 

Canyon Retort 6.89E-05 5.35E-05 6.17E-05

Florida 

Canyon Retort 3.08E-05 1.65E-05 1.34E-05

Florida 

Canyon Retort 5.07E-05 3.68E-06 4.82E-05 3.47E-04 3.86E-05 8.17E+00 5.39E-10 9 8 5.99E-11 5.20E+00 1.80E-10 2.08E+01

Jerritt Canyon Carbon Kiln 5.10E+00 2.23E+00 1.60E+00 8.93E+00 2.98E+00 3.48E+00 3 2 1.16E+00 1.16E+00

Jerritt Canyon Melt Furnace 3.82E-01 1.65E+01 1.76E+01 3.45E+01 1.15E+01 1.45E+01 9.32E+01 3 2 3.11E+01 3.22E+01 3.11E+01 3.22E+01

Lone Tree Electrowinning 1.39E+00 7.68E-01 1.16E+00

Lone Tree Electrowinning 7.02E-01 6.11E+00 7.76E-01 1.09E+01 1.82E+00 4.50E+00 6 5 7.50E-01 1.50E+00

Lone Tree Elecrowinning 1.92E-01 7.15E+00 7.82E-02

Lone Tree Electrowinning 6.18E+00 2.53E-01 1.03E-01 1.40E+01 2.33E+00 1.14E+01 6 5 1.90E+00 3.80E+00

Lone Tree Electrowinning 2.67E+00 1.30E+00 5.00E-01 4.47E+00 1.49E+00 1.20E+00 3 2 4.01E-01 4.01E-01

Lone Tree Preg Tank 1.97E+00 3.29E+00 1.72E+01

Lone Tree Preg Tank 9.17E+00 2.14E+01 3.68E+01 8.98E+01 1.50E+01 2.06E+01 1.72E+02 6 5 2.87E+01 3.18E+01 5.74E+01 6.31E+01
23

Appendix C. Mercury Emissions Data for the Carbon Processes without Mercury Retorts Affected Source (lb/ton concentrate)

Facility Process type

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton) Unit var

No. of runs 

per unit

DF (n-1) 

per unit

Var of unit 

average Facility var

Vw (m = 3 

per unit) Facility Vw

Round Mountain Electrowinning 1.82E-02 7.93E-02 1.90E-02 1.16E-01 3.88E-02 1.23E-03 3 2 4.09E-04 4.09E-04

Round Mountain Melt Furnace 1.49E-04 1.80E-03 1.77E-03

Round Mountain Melt Furnace 3.49E-02 9.59E-03 1.85E-02 6.67E-02 1.11E-02 1.83E-04 6 5 3.05E-05 6.10E-05

Round Mountain Carbon Kiln 2.57E-03 2.86E-03 1.56E-03

Round Mountain Carbon Kiln 1.52E-02 1.02E-02 1.59E-02 4.83E-02 8.05E-03 0.058 4.33E-05 6 5 7.22E-06 4.47E-04 1.44E-05 4.85E-04

Cortez Pipeline Carbon Kiln 1.12E-03 6.42E-04 2.94E-03

Cortez Pipeline Carbon Kiln 2.59E-03 1.76E-03 1.12E-03 1.02E-02 1.70E-03 8.27E-07 6 5 1.38E-07 2.76E-07

Cortez Pipeline Carbon Kiln 1.26E-02 9.36E-03 3.67E-03

Cortez Pipeline Carbon Kiln 6.13E-04 2.64E-04 2.52E-04 2.67E-02 4.45E-03 2.81E-05 6 5 4.68E-06 9.36E-06

Cortez Pipeline Electrowinning 2.58E-02 1.92E-02 2.99E-02

Cortez Pipeline

Electro Winning 

System 1.41E-02 3.58E-03 8.79E-03 1.01E-01 1.69E-02 1.01E-04 6 5 1.68E-05 3.36E-05

Cortez Pipeline Electrowinning 1.40E-02 3.55E-03 6.32E-03

Cortez Pipeline

Electro Winning 

System 5.30E-03 5.62E-03 2.49E-03 3.73E-02 6.21E-03 1.66E-05 6 5 2.77E-06 5.53E-06

Cortez Pipeline Preg Tank 1.01E-01 1.61E-01 8.80E-02

Cortez Pipeline

Pregnant and Barren 

Tanks 3.25E-03 2.44E-03 2.50E-03 3.58E-01 5.96E-02 4.50E-03 6 5 7.50E-04 1.50E-03

Cortez Pipeline Melt Furnace 2.67E-03 1.21E-03 1.84E-03 5.72E-03 1.91E-03 5.37E-07 3 2 1.79E-07 1.79E-07

Cortez Pipeline Melt Furnace 1.43E-04 1.79E-04 1.35E-04 4.57E-04 1.52E-04 5.53E-10 3 2 1.84E-10 1.84E-10

Cortez Pipeline Fusion furnace 5.23E-03 1.37E-02 2.32E-03 2.13E-02 7.09E-03 0.098 3.52E-05 3 2 1.17E-05 7.86E-04 1.17E-05 1.56E-03

Average of 

top 2: 0.078 tDF: 43Vb: 3.08E-04

Vw 

(unpooled): 1.02E-03

t(.99): 2.42
24

Appendix D. Mercury Emissions Data for the Non-Carbon Concentrate Affected Source (lb/ton concentrate)

Facility Unit 

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Run 4 

(lb/ton)

Run 5 

(lb/ton)

Unit 

sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs per 

unit

DF (n-1) 

per unit

Varianc

e of unit 

average

Facility 

variance

Vw (m = 

3 per 

unit)

Facility 

Vw

Coeur 

Rochester 

Refinery 

Furnace 5.96E-02 1.17E-01 2.28E-02

Coeur 

Rochester 

Refinery 

Furnace 2.47E-02 1.20E-02 2.94E-02 2.66E-01 4.43E-02 1.53E-03 6 5 2.55E-04 5.10E-04

Coeur 

Rochester Retorts #1 & #2 3.41E-03 3.45E-03 9.24E-05 2.31E-03 1.95E-03

Coeur 

Rochester Retorts #1 & #2 2.93E-04 1.53E-02 4.20E-03

Coeur 

Rochester Retorts #1 & #2 4.17E-05 1.84E-04 5.39E-05 3.13E-02 2.84E-03 0.047 1.96E-05 11 10 1.78E-06 2.57E-04 6.52E-06 5.17E-04

Midas 

Operations

Refinery 

Furnace 1 & 2 1.60E-02 2.63E-02 4.55E-02

Midas 

Operations

Refinery 

Furnace 1 & 2 1.73E-01 2.17E-01 4.41E-02

Midas 

Operations

Refinery 

Furnace 1 & 2 1.10E-02 2.89E-02 1.73E-02 5.79E-01 6.43E-02 5.74E-03 9 8 6.38E-04 1.91E-03

Midas 

Operations Retort A 2.32E-03 1.79E-03 1.46E-03

Midas 

Operations Retort A 1.25E-03 6.01E-02 3.41E-02

Midas 

Operations Retort A 4.07E-05 3.18E-05 3.72E-05 1.01E-01 1.12E-02 4.56E-04 9 8 5.07E-05 1.52E-04

Midas 

Operations Retort B 2.78E-04 1.07E-05 7.36E-06

Midas 

Operations Retort B 4.22E-03 4.48E-03 5.66E-03

Midas 

Operations Retort B 9.51E-04 1.45E-03 1.02E-03 1.81E-02 2.01E-03 0.078 4.72E-06 9 8 5.24E-07 6.89E-04 1.57E-06 2.07E-03

Average 

of top 2: 6.23E-02 1.55E-03 t DF: 39 Vb: 2.37E-04

Vw 

(unpoole

d): 2.58E-03

t(.99): 2.43
25

Appendix E. New Source MACT Floors

Ore Pretreatment Processes

Facility Unit 

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit 

sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 3 

per unit)

Facility 

Vw

Goldstrike Roaster Ore Preheater 3.23E-07 5.03E-07 3.60E-07

Goldstrike Roaster Ore Preheater 8.61E-07 5.96E-07 5.17E-07

Goldstrike Roaster Ore Preheater 1.79E-06 1.39E-06 2.65E-07

Goldstrike Roaster Ore Preheater 2.19E-06 1.13E-06 2.65E-07 1.02E-05 8.48E-07 4.12E-13 12 11 3.43E-14 1.37E-13

Goldstrike Roaster Ore Preheater 8.68E-06 4.71E-06 1.71E-06

Goldstrike Roaster Ore Preheater 2.36E-05 5.05E-06 7.86E-07

Goldstrike Roaster Ore Preheater 8.52E-07 8.52E-07 3.93E-07

Goldstrike Roaster Ore Preheater 1.64E-06 8.52E-07 3.93E-07 4.95E-05 4.12E-06 4.40E-11 12 11 3.67E-12 1.47E-11

Goldstrike Roaster 7.25E-05 5.71E-05 5.26E-05

Goldstrike Roaster 1.25E-05 1.25E-05 1.71E-05

Goldstrike Roaster 1.95E-05 1.73E-05 1.31E-05 2.74E-04 3.05E-05 5.47E-10 9 8 6.08E-11 1.82E-10

Goldstrike Roaster/Calcine quench 4.35E-06 2.96E-06 2.87E-06 1.02E-05 3.39E-06 6.86E-13 3 2 2.29E-13 2.29E-13

Goldstrike Roaster/Calcine quench 3.55E-06 3.76E-06 3.32E-06 1.06E-05 3.54E-06 4.72E-14 3 2 1.57E-14 1.57E-14

Goldstrike Autoclave 2.59E-07 4.01E-07 4.70E-07 1.13E-06 3.77E-07 1.16E-14 3 2 3.87E-15 3.87E-15

Goldstrike Autoclave 6.57E-07 7.71E-07 5.50E-07 1.98E-06 6.59E-07 1.23E-14 3 2 4.09E-15 4.09E-15

Goldstrike Autoclave 1.42E-06 1.65E-07 1.81E-07 1.77E-06 5.90E-07 5.21E-13 3 2 1.74E-13 1.74E-13

Goldstrike Autoclave 1.42E-06 8.32E-07 4.62E-07 2.71E-06 9.03E-07 4.49E-05 2.32E-13 3 2 7.72E-14 6.50E-11 7.72E-14 1.98E-10

Average = 4.49E-05

DF = 42

t = 2.42

Vb = 6.50E-11

Vw = 1.98E-10

Vt = 2.63E-10

Facility 

99% UPL 

= 8.41E-05
26

Carbon Processes with Mercury Retorts

Facility Unit 

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 3 

per unit)

Facility 

Vw

Marigold EW, P/B 3.68E-01 5.43E-01 4.32E-01 1.34E+00 4.48E-01 7.86E-03 3 2 2.62E-03 2.62E-03

Marigold Retort 7.72E-02 1.14E-01 9.07E-02

Marigold Retort 2.48E-03 1.14E-02 1.37E-03 2.97E-01 4.95E-02 2.52E-03 6 5 4.20E-04 8.41E-04

Marigold Furnace 8.49E-02 4.11E-02 2.52E-02

Marigold Melt Furnace 1.00E-02 1.09E-02 1.74E-02 1.90E-01 3.16E-02 8.13E-04 6 5 1.36E-04 2.71E-04

Marigold Carbon Kiln 7.52E-03 6.29E-03 6.99E-03

Marigold Carbon Kiln 7.36E-04 2.45E-04 3.93E-04 2.22E-02 3.69E-03 5.33E-01 1.27E-05 6 5 2.12E-06 3.18E-03 4.25E-06 3.74E-03

Average = 5.33E-01

DF = 17

t = 2.57

Vb = 3.18E-03

Vw = 3.74E-03

Vt = 6.92E-03

Facility 99% 

UPL = 7.46E-01

Carbon Processes without Mercury Retorts

Facility Unit

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit 

sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs 

per 

unit

DF (n1) per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 3 

per unit)

Facility 

Vw

Round Mountain Electrowinning 1.82E-02 7.93E-02 1.90E-02 1.16E-01 3.88E-02 1.23E-03 3 2 4.09E-04 4.09E-04

Round Mountain Melt Furnace 1.49E-04 1.80E-03 1.77E-03

Round Mountain Melt Furnace 3.49E-02 9.59E-03 1.85E-02 6.67E-02 1.11E-02 1.83E-04 6 5 3.05E-05 6.10E-05

Round Mountain Carbon Kiln 2.57E-03 2.86E-03 1.56E-03

Round Mountain Carbon Kiln 1.52E-02 1.02E-02 1.59E-02 4.83E-02 8.05E-03 0.058 4.33E-05 6 5 7.22E-06 4.47E-04 1.44E-05 4.85E-04

Average = 5.80E-02

DF = 12

t = 2.68

Vb = 4.47E-04

Vw = 4.85E-04

Vt = 9.32E-04

Facility 

99% UPL = 1.40E-01
27

Non-Carbon Concentrate

Facility Unit 

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Run 4 

(lb/ton)

Run 5 

(lb/ton)

Unit 

sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs 

per 

unit

DF

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw 

(m = 3 

per 

unit)

Facility 

Vw

Coeur 

Rochester 

Mine

Refinery 

Furnace 5.96E-02 1.17E-01 2.28E-02

Coeur 

Rochester 

Mine

Refinery 

Furnace 2.47E-02 1.20E-02 2.94E-02 2.66E-01 4.43E-02 1.53E-03 6 5 2.55E-04 5.10E-04

Coeur 

Rochester 

Mine

Retorts 

#1 & #2 3.41E-03 3.45E-03 9.24E-05 2.31E-03 1.95E-03

Coeur 

Rochester 

Mine

Retorts 

#1 & #2 2.93E-04 1.53E-02 4.20E-03

Coeur 

Rochester 

Mine Retort 4.17E-05 1.84E-04 5.39E-05 3.13E-02 2.84E-03 4.71E-02 1.96E-05 11 10 1.78E-06 2.57E-04 6.52E-06 5.17E-04

Average 

= 4.71E-02

DF = 15

t = 2.60

Vb = 2.57E-04

Vw = 5.17E-04

Vt = 7.74E-04

Facility 

99% 

UPL = 1.19E-01
28

Appendix F. Beyond the Floor – Ore Pretreatment

Facility Unit 

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 

3 per 

unit)

Facility 

Vw

Gold 

Quarry

Roaster/Calcine 

quench 1.35E-05 9.56E-06 1.37E-05

Gold 

Quarry

Roaster/Calcine 

quench 1.05E-05 1.33E-05 1.69E-05

Gold 

Quarry

Roaster/Calcine 

quench 8.45E-06 1.05E-05 9.66E-06 1.06E-04 1.18E-05 7.33E-12 9 8 8.14E-13 2.44E-12

Gold 

Quarry

Roaster Ore 

Preheater 3.81E-06 1.62E-06 1.36E-06

Gold 

Quarry

Roaster Ore 

Preheater 7.90E-06 7.51E-06 4.63E-05

Gold 

Quarry

Roaster Ore 

Preheater 2.45E-06 1.04E-06 9.09E-07 7.29E-05 8.10E-06 2.12E-10 9 8 2.35E-11 7.06E-11

Gold 

Quarry Roaster 8.99E-07 6.97E-07 7.87E-07

Gold 

Quarry Roaster 1.27E-06 1.61E-06 6.19E-07

Gold 

Quarry Roaster 4.92E-07 2.75E-07 3.56E-07 7.00E-06 7.78E-07 1.86E-13 9 8 2.07E-14 6.21E-14

Gold 

Quarry

Roaster Ore 

Grinder 1.66E-06 2.06E-06 1.48E-06

Gold 

Quarry

Roaster Ore 

Grinder 1.50E-06 4.82E-06 1.75E-06 1.33E-05 2.21E-06 1.67E-12 6 5 2.79E-13 5.58E-13

Gold 

Quarry

Roaster/Calcine 

quench 1.67E-05 1.36E-05 9.55E-06

Gold 

Quarry

Roaster/Calcine 

quench 1.27E-05 1.46E-05 2.11E-05

Gold 

Quarry

Roaster/Calcine 

quench 1.03E-05 1.31E-05 1.32E-05 1.25E-04 1.39E-05 3.68E-05 1.19E-11 9 8 1.32E-12 2.60E-11 3.96E-12 7.77E-11

Goldstrike

Roaster Ore 

Preheater 1.82E-07 2.84E-07 2.03E-07

Goldstrike

Roaster Ore 

Preheater 5.58E-07 3.86E-07 3.35E-07

Goldstrike

Roaster Ore 

Preheater 1.16E-06 9.01E-07 1.72E-07

Goldstrike

Roaster Ore 

Preheater 1.42E-06 7.29E-07 1.72E-07 6.49E-06 5.41E-07 1.78E-13 12 11 1.48E-14 5.94E-14

Goldstrike

Roaster Ore 

Preheater 4.90E-06 2.66E-06 9.66E-07

Goldstrike

Roaster Ore 

Preheater 1.53E-05 3.27E-06 5.09E-07

Goldstrike

Roaster Ore 

Preheater 5.52E-07 5.52E-07 2.55E-07

Goldstrike

Roaster Ore 

Preheater 1.06E-06 5.52E-07 2.55E-07 3.08E-05 2.57E-06 1.81E-11 12 11 1.51E-12 6.04E-12
29

Facility Unit 

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 

3 per 

unit)

Facility 

Vw

Goldstrike Roaster 1.56E-04 1.23E-04 1.14E-04

Goldstrike Roaster 2.70E-05 2.70E-05 3.70E-05

Goldstrike Roaster 3.67E-05 3.26E-05 2.47E-05 5.78E-04 6.42E-05 2.65E-09 9 8 2.95E-10 8.85E-10

Goldstrike

Roaster/Calcine 

quench 8.18E-06 5.56E-06 5.40E-06 1.91E-05 6.38E-06 2.43E-12 3 2 8.09E-13 8.09E-13

Goldstrike

Roaster/Calcine 

quench 6.67E-06 7.07E-06 6.25E-06 2.00E-05 6.66E-06 8.04E-05 1.67E-13 3 2 5.57E-14 2.97E-10 5.57E-14 8.92E-10

Jerritt 

Canyon Ore dryer 4.06E-06 8.58E-06 5.77E-06

Jerritt 

Canyon Ore dryer 1.15E-06 9.71E-06 3.42E-06 3.27E-05 5.45E-06 1.05E-11 6 5 1.76E-12 3.51E-12

Jerritt 

Canyon Roaster 4.42E-05 4.47E-05 5.14E-05

Jerritt 

Canyon Roaster 4.48E-05 2.07E-05 2.99E-05

Jerritt 

Canyon Roaster 7.01E-06 7.92E-06 8.36E-06 2.59E-04 2.88E-05 3.31E-10 9 8 3.68E-11 1.10E-10

Jerritt 

Canyon Roaster 5.50E-05 4.65E-05 2.82E-05

Jerritt 

Canyon Roaster 5.80E-06 4.30E-06 4.65E-06 1.44E-04 2.41E-05 5.83E-05 5.16E-10 6 5 8.60E-11 1.25E-10 1.72E-10 2.86E-10

Twin 

Creeks Autoclave 1.66E-05 4.34E-05 3.06E-05

Twin 

Creeks Autoclave 2.35E-05 7.76E-05 8.70E-06

Twin 

Creeks Autoclave 7.07E-05 3.51E-05 3.25E-05

Twin 

Creeks Autoclave 6.40E-05 3.99E-05 3.29E-05

Twin 

Creeks Autoclave 2.99E-05 5.92E-05 7.98E-05

Twin 

Creeks Autoclave 3.18E-05 2.09E-05 1.86E-05

Twin 

Creeks Autoclave 2.59E-06 2.42E-06 2.29E-06 7.23E-04 3.44E-05 5.75E-10 21 20 2.74E-11 1.92E-10

Twin 

Creeks Autoclave 3.42E-05 1.64E-05 1.60E-05

Twin 

Creeks Autoclave 2.60E-05 1.49E-05 1.04E-05

Twin 

Creeks Autoclave 1.46E-05 2.72E-05 2.39E-05

Twin 

Creeks Autoclave 1.06E-05 7.50E-06 6.36E-06

Twin 

Creeks Autoclave 6.12E-06 5.74E-06 5.88E-06 2.26E-04 1.51E-05 4.95E-05 8.16E-11 15 14 5.44E-12 3.28E-11 2.72E-11 2.19E-10
30

Facility Unit 

Run 1 

(lb/ton)

Run 2 

(lb/ton)

Run 3 

(lb/ton)

Unit sum 

(lb/ton)

Unit 

average 

(lb/ton)

Facility 

total 

(lb/ton)

Unit 

variance

No. of 

runs per 

unit

DF 

(n-1) 

per 

unit

Variance 

of unit 

average

Facility 

variance

Vw (m = 

3 per 

unit)

Facility 

Vw

Average 

of top 5: 5.62E-05 t DF: 123 Vb:

3.00E11

Vw 

(unpooled

): 3.69E-10

56 t(.99): 2.36