From: Mike Elges <melges@ndep.nv.gov>

Date: Thu, Sep 23, 2010 at 4:40 PM

Subject: 

To: "Chuck French (french.chuck@gmail.com)" <french.chuck@gmail.com>

Cc: Rob Bamford <rbamford@ndep.nv.gov>

Chuck,

Please find attached the information that we discussed regarding the monthly emissions testing 

and process monitoring being conducted at the Jerritt Canyon roasters. As we described, NDEP 

believes that this data helps support how continuous monitoring of process and pollution control 

device parameters provides reliable information to ensure that Hg emissions from the roasters are 

being controlled appropriately. Further, the data supports that even when the system deviates 

from a discrete set point that the Hg controls have sufficient capability to compensate for 

variability. Therefore, it is not necessary to require immediate shutdown of the system. It is 

more appropriate to allow for system corrections to bring operations back into the established 

parameters.

The NDEP continues to support the concept that the federal rule be structured such that 

continuous parametric monitoring of roaster process and/or pollution control device parameters 

coupled with routine emissions testing of roasters is an appropriate methodology for ensuring 

compliance with the proposed Hg standard. We believe that semi-annual emissions testing based 

on Method 29 (or an alternative method approved by the Permitting Authority) for the first two 

years, coupled with continuous parametric monitoring will provide adequate information to 

ensure ongoing compliance. Assuming that the two years results of the Method 29 tests are 

relatively consistent, we believe that the testing frequency should be reduced to an annual 

schedule.

The NDEP also believes that the proposed rule should be revised to rely upon Method 29 as the 

primary test method for measuring Hg emissions for demonstrating compliance with the 

proposed standard. We believe that this Method is best suited for the types of processes and gas 

streams found in this industry. Further, it is our understanding that the proposed standards have 

been established based solely on data measured by Method 29. To date, the NDEP is unaware of 

any analyses or demonstration that correlates the data collected through the other proposed test 

methods. In particular, we are concerned that factors such as particulate, moisture and sample 

volume can have a significant negative effect on the results obtained from the different methods.

For example, units throughout this industry differ in whether the gas streams contain particulatebound mercury or not. Utilizing a test method that does not appropriately account for the 

particulate-bound portion of the sample will result in Hg emissions not being accurately 

measured. Should information become available that demonstrates that alternative methods can 

provide consistent results without significant variance between the methods, the NDEP would 

support their use. Therefore, we are recommending that the rule be revised to provide for the use 

of alternative methods by providing language that allows the Permitting Authority the ability to

approve an alternative test method. We believe that this provides an appropriate mechanism to 

approve other test methods once they’ve been determined to provide comparable results.
If you have any questions, or would like to discuss these items in more detail, please let me 

know.

Thanks,

Mike Elges

See attached file: Jerritt Canyon Roasters v4.doc
Page 1 of 15

Jerritt Canyon Roasters’ Test Data

A Review of Parametric Monitoring and Emissions

Nevada Division of Environmental Protection

Bureau of Air Pollution Control / Nevada Mercury Control Program

Introduction

Prior to the review and subsequent development of robust continuous parametric monitoring the 

Jerritt Canyon roasters historically demonstrated poor mercury recovery and variable emissions 

of mercury, SOx and PM. The October 2008 Consent Decree required a thorough engineering 

design review of the roasters’ emissions controls to define and “fine-tune” the optimal operating 

parameters to minimize mercury emissions. The Consent Decree also required frequent stack 

testing to evaluate the various operational parameters’ set-points, to define ranges for alarms and 

to define interlock trigger values. The process of determining the optimal operational parameters 

is still a work in progress as an adequate database must be established to represent the range of 

facility/roaster operations. The Consent Decree test events have demonstrated the efficacy of 

continuous parametric monitoring with notable reductions in mercury emissions and less 

variability in measured emissions.

Jerritt Canyon has 2 fluidized bed roasters that oxidize run of mill ore prior to Carbon-In-Leach 

(CIL) and/or Merrill-Crowe (MC) zinc precipitation. The roasters emissions controls were 

constructed in the late 1980s. They roasters are duplicate systems, but operate autonomously. 

Each roaster has an emissions control system for the control of PM, SO2 and Hg. 

Hot, oxidized ore (calcine) exiting the roaster is quenched with process water into a slurry tank 

to await CIL/MC. The combustion exhaust and quench steam is then routed to an entoleter to 

remove particulate from the gas stream. The entoleter utilizes high-pressure water and a 

spinning “squirrel cage” to impact particulate with water droplets. After the entoleter, the 

exhaust gas travels through four wet scrubbers with packed media (SO2, Hg#1, Hg#2 and tail). 

See Figure 1, below. The system was re-configured in 2009 to add mercury scrubber #2, and to 

switch from NaOCl as a reagent in liquid form to chlorine gas as the reagent.
Page 2 of 15

Figure 1. Jerritt Canyon Roaster Emissions Control Train Configuration

The SO2 scrubber utilizes lime to scrub SOx. The mercury scrubber #1 utilizes chlorine gas to 

react with elemental mercury to form mercuric chloride. Mercury scrubber #2 reacts the 

mercuric chloride from Mercury Scrubber #1 with any remaining mercury in the exhaust gas 

stream to create mercurous chloride (calomel). The tail gas scrubber uses water to “polish” any 

remaining pollutants. Lime may be added to any of the four scrubbers to maintain desired 

process pH. The calomel is a precipitate which may be filtered and collected from the scrubbers’ 

liquor.

Prior to the Consent Decree of October 2009, the company had a history of inconsistent mercury 

emissions and excess emissions events which became an ongoing compliance issue. After 

several enforcement actions were taken by the NDEP, the NDEP began a detailed investigation 

into the operations of the roasters and emissions controls to determine what was needed to bring 

the roasters back into compliance. 

The investigation began with a review of the Title 5 permit, which required nominal work 

practices related to the performance of the mercury emissions control. The requirements 

contained in the Title 5 permit, were to monitor (7) points for a “specified operating range”; 

however, no ranges are actually specified, and monitoring was required to be performed only 

once per day. The requirements had no operating ranges, alarms or interlocks. The chemistry of 

the desired reactions of the mercury scrubber were also absent. 

Table 1and Figure 2, below, display all available roaster testing data for the Jerritt Canyon 

roasters. In Table 1, data is listed in descending order, starting with the most recent tests. Tests 

shaded in green were performed under the Consent Decree and expanded work practice 

standards. Figure 2 displays the same data on a graph. 
Page 3 of 15

Table 1. All Available Roaster Mercury Emissions Test Data (Green-shaded Fields are Consent Decree Tests).

Date Method

West (#40)

gr/dscf Hg Date Method

East (#42)

gr/dscf Hg

06/17/2010 Method 29 2.02E-05 06/15/2010 Method 29 2.77E-05

04/29/2010 Method 29 1.60E-05 04/27/2010 Method 29 1.67E-05

02/24/2010 Method 29 7.58E-05 03/29/2010 Method 29 3.29E-05

01/22/2010 Method 29 1.39E-04 02/22/2010 Method 29 9.45E-04 [3]

12/05/2009 Method 29 3.25E-04 [1] 01/20/2010 Method 29 1.79E-04

06/13/2008 Method 29 2.27E-04 12/03/2009 Method 29 1.70E-03 [2]

05/08/2008 Ontario Hydro 1.36E-03 06/12/2008 Method 29 6.55E-04

07/27/2007 Ontario Hydro 4.70E-04 06/12/2008 Ontario Hydro 8.61E-04

07/25/2007 Method 29 4.93E-03 05/20/2008 Ontario Hydro 2.17E-02

10/25/2006 Ontario Hydro 1.80E-02 07/27/2007 Ontario Hydro 5.37E-04

12/02/2004 Method 29 2.65E-03 07/26/2007 Method 29 1.58E-03

12/02/2004 Method 29 4.70E-03 10/27/2006 Ontario Hydro 2.96E-03

08/31/2004 Method 29 8.00E-04 12/01/2004 Method 29 3.00E-04

07/20/2004 Method 29 9.79E-02 11/30/2004 Method 29 2.00E-04

10/02/2002 Method 29 2.23E-03 08/31/2004 Method 29 3.00E-03

10/02/2002 Method 29 2.10E-01 07/20/2004 Method 29 1.09E-01

05/12/2000 Method 29 2.57E-02 10/01/2002 Method 29 7.33E-04

04/14/2000 Method 29 2.75E-02 10/01/2002 Method 29 1.40E-01

04/13/2000 Method 29 8.80E-03

[1] The entoleter pressure drop was also below the set point for all three runs during testing of the west roaster. Also during testing the SO2 heat exchangers were bypassed.

[2] They state that the high emission rate from the east roaster is a result of combustion in the 2nd stage bed level. Although Jerritt would normally shut down the roaster if combustion was detected in 

the 2nd stage, they choose not to shut down in order to continue with testing. Additionally, Jerritt states that increased SO2 in the roasters can change the effectiveness of the calomel system by 

consuming chlorine gas.

[3] While removing the test probe from the stack at the end of run #1 of the east roaster, the probe nozzle caught the edge of the sample port and broke off. During sample train recovery no glass 

shards were found in the filter. All three runs of the east roaster exceeded the emission limit set in the consent decree. The average total gaseous mercury emitted by the east roaster was ten times 

greater than the average amount emitted from the west roaster. The east roaster also had a lower average flow rate, by around 2,000 dscfm, then the west roaster.The moisture content in the east 

roaster stack was greater than that of the west roaster. The average moisture content in the east roaster stack was 6.04%, while in the west roaster it was 3.54%.
Page 4 of 15

Figure 2. Graph of All Available Mercury Emissions Test Data
Page 5 of 15

To evaluate the existing state of operations the NDEP required a series of multiple, simultaneous, 

OHM tests at specific locations in the roaster control train to characterize the operations and 

chemical processes of the system (see Figures 3 and 4, below).

The OHM tests demonstrate that the East roaster had a 70% greater particulate loading after the 

entoleter than the West roaster at 0.0103 lb/hr. Following the entoleter, the SO2 scrubber 

appears to add particulate matter to the exhaust gas by 300%, and mercury emission actually 

increased across the mercury scrubber by 0.7 lb/hr. Somehow, the tail gas scrubber then drops 

the mercury emissions from 1.0 lb/hr mercury to 0.9 lb/hr at the stack. This is suspicious as the 

tail gas scrubber does not use a chemical reagent to capture mercury but rather it only utilizes 

water as its scrubber liquor. Mercury exiting the stack was 39% oxidized mercury and 61% 

elemental, potentially indicating some successful conversion and collection of elemental mercury 

to the soluble oxidized form; however, the system still fails overall, emitting 0.9 lb/hr mercury. 

The majority of the emissions are in the elemental form, indicating that rate of elemental to 

soluble oxidized form conversion was not adequate and that the management of the control 

system’s chemistry is lacking.

The OHM tests demonstrate that for the West Roaster, particulate loading after the entoleter was 

measured at 0.0072 lb/hr and subsequent mercury measured in the exhaust gas at each scrubber 

in the control train decreased until exiting the stack at 0.04 lb/hr. The mercury scrubber 

performed the bulk of mercury removal with an input of 1.46 lbs/hr and an output of 0.06 lb/hr. 

Following the entoleter, the SO2 scrubber appears to add particulate matter by 56%. The SO2 

scrubber appears to act as a “store house” for PM. While emissions at the West roaster were 

low(er), the mercury exiting the stack was 65.3% oxidized, and 31.5% elemental. During its 

path through the scrubber train, the exhaust gas mercury enters as 40% oxidized, increases to 

47%, and then 72% before dropping back down to its final 65%. The mercury scrubber appears 

to successfully oxidize mercury: 47% oxidized entered the Hg scrubber, and 72% exited; 

however the oxidized mercury is not being captured by the scrubber liquor. More oxidized 

mercury exits this system than enters—the chemical reactions are clearly increasing the portion 

of oxidized mercury and then not catching it in its soluble form in the scrubber liquor. Clearly 

the chemistry is an issue.
Page 6 of 15

Figure 3. OHM Testing, May 2008 – West Roaster

NaOC

l

Hg PM 0.0072 (0.5%)

Hg2+ 0.6045 (40%)

Hg0 0.8990 (59.5%)

Total = 1.4622 lbs/hr

Hg PM 0.0127 (0.9%)

Hg2+ 0.6819 (46.6%)

Hg0 0.7676 (52.5%)

Total = 1.4622 lbs/hr

Hg PM 0.0039 (6%)

Hg2+ 0.0465 (72.2%)

Hg0 0.0140 (21.7%)

Total = 0.0644 lb/hr

Hg PM 0.0014 (3.2%)

Hg2+ 0.0290 (65.3%)

Hg0 0.0140 (31.5%)

Total = 0.0444 lb/hr
Page 7 of 15

Figure 4. OHM Testing, May 2008 – East Roaster

NaOCl

Hg PM 0.0103 (0.7%)

Hg2+ 0.7882 (51.3%)

Hg0 0.7390 (48.0%)

Total = 1.5107 lbs/hr

Hg PM 0.0304 (2.4%)

Hg2+ 0.4175 (33.3%)

Hg0 0.8068 (64.3%)

Total = 1.2548 lbs/hr

Hg PM 0.0078 (0.4%)

Hg2+ 0.4577 (23.5%)

Hg0 1.4804 (76.1%)

Total = 1.9459 lbs/hr

Hg PM 0.0016 (0.002%)

Hg2+ 0.3558 (38.9%)

Hg0 0.5535 (60.5%)

Total = 0.9143 lb/hr
Page 8 of 15

When sulfur slips through to the NaOCl scrubber, the sulfur reacts with NaOCl pulling out the 

oxygen and bonding with it. NaCl is stable and with the chlorine having a full outer shell 

containing 8 electrons. Sodium has 1 electron and shares that electron with chlorine. NaCl will 

almost always be favored over HgCl2 because both the sodium and chlorine electrons are happy 

with their outer shells filled. The sulfur molecule has 2 unfilled electrons in its outer shell so 2 

oxygen will bond with the sulfur to make sulfur dioxide leaving the mercury unreactive. When 

there is a lot of sulfur in the gas stream, equation (1) will be favored over equation (2).

S + Hg0 + 2NaOCl → 2NaCl + SO2 + Hg0 (1)

S + Hg0 + 2NaOCl → HgCl2 + Na2 + SO2 (2)

Ideally, we do not want sulfur present in the system in order to allow equation (3) to be favored.

Hg0 + 4NaOCl → 2HgCl2 + 2Na2O + 2O2 (3)

The updated emission control system at Jerritt Canyon adds chorine gas to the NaOCl scrubber 

in order to produce more mercuric chloride since there is some sulfur present in the gas stream. 

This provides ample chlorine for both mercury and sodium to bond with as shown in equation 

(4). 

2S + Hg0 + Cl2 + 2NaOCl → HgCl2 + 2NaCl + 2SO2 (4)

New WPS Defined by Consent Decree

Data from OHM testing was used to establish new work practice standards for several process 

and pollution control devices to ensure continuous compliance with the emissions requirements. 

The new standards focused on scrubber and entoleter performance and the desired chemical 

reactions at various stages of the control process. pH and ORP values were added as indicators 

of the optimal chemical reactions. Scrubber and entoleter pressure drop values were added for 

each unit. For each work practice parameter there is a set point, a deviation range with an alarm 

and an interlock. 
Page 9 of 15

Table 2. NDEP-Developed Operational Parameters for Jerritt Roaster 

(A) Entoleter

Parameter Set Point Deviation Alarm Interlock

pressure drop 30 in. WC 5 in. WC 20 in. WC

(B) SO2 Scrubber

Parameter Set Point Deviation Alarm Interlock

pressure drop 8 in. WC 5 in. WC --

pH 8.0 0.2 7.5

(C) Mercuric chloride (HgCl2) Scrubber

Parameter Set Point Deviation Alarm Interlock

pressure drop 8 in. WC 5 in. WC --

chlorine feed pressure 5 psi

pH 6.9 0.2 7.5

ORP 900 25 850

(D) Calomel (HgCl) Scrubber – Hg Scrubber #2

Parameter Set Point Deviation Alarm Interlock

pressure drop 8 in. WC 5 in. WC

pH 6.9 7.5

Solution temperature 

(heat exchanger)

85o F 3o F 104o F

(E) Tail Gas Scrubber

Parameter Set Point Deviation Alarm Interlock

pressure drop 4 in. WC 2 in. WC --

pH 8.0 0.2 7.0

The deviation alarm provides a range with which the system may deviate from a set point 

without requiring system shutdown. The deviation alarm provides an opportunity to bring a 

parameter back to its optimal set point without adversely impacting the mercury emission profile, 

assuming that the sum of all work practice parameters are robust, as is the case demonstrated by 

the Jerritt Canyon data below. 

Conclusion

The emissions testing conducted demonstrates that maintaining roaster circuit operations within 

established process and pollution control device operational parameters ensures that emissions 

reduction are maximized. The testing also demonstrates that excursions from the established set 

point, within a reasonable range, are not by default excess emission events. The control systems 

have demonstrated sufficient capability to absorb additional Hg emissions that may be generated 

without immediately exceeding the established Hg emissions limitations. Therefore, it is not 

necessary to require immediate shutdown of the system. Rather, it is more appropriate to allow 

the operator to bring the system back into the established range(s) of the operational parameters.
Appendix: Consent Decree Test Data

Page 10 of 15

December 2009 

Parameter

East 

Roaster 

Tested

West 

Roaster 

Tested

Set 

Point

Deviation

Alarm Interlock

Entoleter DP (in. WC) 30.3 19.4 25 5 15

SO2 Scrubber DP (in. WC) 8.9 1.5 8 5 --

SO2 Scrubber pH 8 7.9 8 0.2 7.5

HgCl2 Scrubber DP (in. WC) 3 1.9 8 5 --

HgCl2 Scrubber pH 6.9 7.6 6.9 0.2 7.5

HgCl2 Scrubber ORP 825 25 750

HgCl – Hg scrubber #2 DP (in. WC) 0.46 2.5 8 5 --

HgCl – Hg scrubber #2 pH 7.1 6.9 6.9 -- 7.5

HgCl – Hg scrubber #2 

solution temp (°F) 85 3 104

Tail gas scrubber DP 0.03 0 4 2 --

Tail gas scrubber pH 8 8 8 0.2 7

No tested values were provided for the solution temperature of mercury scrubber #2, and no ORP values were 

provided for mercury scrubber #1. The pressure drops across mercury scrubber #1, mercury scrubber #2, and the tail 

gas scrubber were lower then the set point determined in the consent decree for both roasters during all three runs. 

The entoleter pressure drop was also below the set point for all three runs during testing of the west roaster. While 

testing the west roaster the pH of mercury scrubber #1 was 7.6 for all test runs, including the method 5 test runs, 

which should have triggered the interlock to shut down the ore roaster system. Also during testing the SO2 heat 

exchangers were bypassed. This process deviation was observed by Joseph Prary of NDEP during a compliance 

inspection, but it is not mentioned any where in the source test report.

In a letter dated January 7, 2010 Jerritt tries to address the cause of their failure to meet the emission limit 

established within the consent decree. They state that the high emission rate from the east roaster is a result of 

combustion in the 2nd stage bed level. Although Jerritt would normally shut down the roaster if combustion was 

detected in the 2nd stage, they choose not to shut down in order to continue with testing. Additionally, Jerritt states 

that increased SO2 in the roasters can change the effectiveness of the calomel system by consuming chlorine gas. 

Jerritt would like to install an additional ORP probe in order to better maintain the ORP value throughout the 

calomel system. 

Thermal 

Unit

Tested 

Production 

(tons/hour)

Permitted 

Throughput 

(tons/hour)

Percent of 

Permitted 

Throughput

Process 

Sample 

Loading 

(ppm)

Mercury Emission Rates (gr/dscf) Average 

Tested 

Hg 

Emissions 

(gr/dscf)

Permitted 

Hg 

Emission 

Rate 

(gr/dscf)

Run #1 Run #2 Run #3

West 

Roaster 70.4 90 78.2% 12.7 5.55x10-4 2.13x10-4 2.08x10-4 3.25x10-4 2.61x10-4

East 

Roaster 68 90 75.6% 11 1.58x10-3 2.12x10-3 1.39x10-3 1.70x10-3 2.61x10-4
Appendix: Consent Decree Test Data

Page 11 of 15

January 2010

Parameter

East 

Roaster 

Tested

West Roaster 

Tested

Set 

Point

Deviation

Alarm Interlock

Entoleter DP (in. WC) 42.7 42.4 25 5 15

SO2 Scrubber DP (in. WC) 1.06 2.3, 7.9, 2.8 8 5 --

SO2 Scrubber pH 9.7 8.03 8 0.2 7.5

HgCl2 Scrubber DP (in. WC) 4.5 1.6 8 5 --

HgCl2 Scrubber pH 6.8 7.0 6.9 0.2 7.5

HgCl2 Scrubber ORP 825 25 750

HgCl – Hg scrubber #2 DP (in. WC) 1.6 3.3 8 5 --

HgCl – Hg scrubber #2 pH 8.3 7.2 6.9 -- 7.5

HgCl – Hg scrubber #2 

solution temp (°F) 85 3 104

Tail gas scrubber DP -3.1 2.7 4 2 --

Tail gas scrubber pH 8 8 8 0.2 7

During testing of the west roaster water supply to the entoleter was lost, and testing was suspended for 50 minutes. 

This process upset was described on the deviations page of the stack test report. The first two runs of the east roaster 

collected less than the required 60 dscf of gas, with 55.7 and 52.24 dscf for runs 1 and 2 respectively. This deviation 

from the method was discovered during run 3 of testing on the east roaster. Joseph Prary of NDEP was on site and 

allowed the two previous runs to be reported. The east roaster was re-traversed over a period of 12 minutes (one 

point per minute) so that run 3 would collect the required 60 dscf of gas.

The west roaster showed higher particulate mercury concentrations than the east roaster. The west roaster also had 

higher particulate during both method 5 and method 29 testing. The east roaster’s flow rate averaged 3941 dscfm, 

which is significantly lower than the 5434 dscfm average seen by the west roaster. This low flow rate was probably 

the cause of the low volume collected during testing.

Average process parameters for the roaster control system during method 29 testing are displayed in the table below. 

No tested values were provided for the solution temperature of mercury scrubber #2, and no ORP values were 

provided for mercury scrubber #1. The pressure drops across mercury scrubber #1, mercury scrubber #2, and the tail 

gas scrubber were well below the set point determined in the consent decree for both roasters during all three runs. 

The pressure drop across the SO2 scrubber was also well below the set point for both roasters; however, during run 

#2 of the west roaster the SO2 scrubber pressure drop was near the set point, but that is the only run where the 

pressure drop neared the set point. While testing the east roaster the pH of mercury scrubber #2 was 8.3 for all 

method 29 test runs, which should have triggered the interlock to shut down the ore roaster system.

Thermal 

Unit

Tested 

Production 

(tons/hour)

Permitted 

Throughput 

(tons/hour)

Percent of 

Permitted 

Throughput

Process 

Sample 

Loading 

(ppm)

Mercury Emission Rates (gr/dscf) Average 

Tested 

Hg 

Emissions 

(gr/dscf)

Permitted 

Hg 

Emission 

Rate 

(gr/dscf)

Run #1 Run #2 Run #3

West 

Roaster

68.9 ore

0.86 coal

90 ore

1.9 coal

76.6% ore

45.4% coal 11.3 1.33x10-4 1.31x10-4 1.52x10-4 1.39x10-4 2.60x10-4

East 

Roaster

70.3 ore

1.64 coal

90 ore

1.9 coal

78.1% ore

86% coal 9.3 2.29x10-4 2.01x10-4 1.08x10-4 1.79x10-4 2.60x10-4
Appendix: Consent Decree Test Data

Page 12 of 15

February 2010

Parameter

East 

Roaster 

Tested

West Roaster 

Tested

Set 

Point

Deviation

Alarm Interlock

Entoleter DP (in. WC) 33 44.6 25 5 15

SO2 Scrubber DP (in. WC) 1.9 1.6 8 5 --

SO2 Scrubber pH 8 7.9 8 0.2 7.5

HgCl2 Scrubber DP (in. WC) 3.1 6.2 8 5 --

HgCl2 Scrubber pH 6.4 6.6 6.9 0.2 7.5

HgCl2 Scrubber ORP 825 25 750

HgCl – Hg scrubber #2 DP (in. WC) 1.8 3.4 8 5 --

HgCl – Hg scrubber #2 pH 6.6 6.6 6.9 -- 7.5

HgCl – Hg scrubber #2 

solution temp (°F) 85 3 104

Tail gas scrubber DP 0.7, 2.6, 

3.4

1.9 4 2 --

Tail gas scrubber pH 8 8 8 0.2 7

While removing the test probe from the stack at the end of run #1 of the east roaster, the probe nozzle caught the 

edge of the sample port and broke off. During sample train recovery no glass shards were found in the filter.

All three runs of the east roaster exceeded the emission limit set in the consent decree. The average total gaseous 

mercury emitted by the east roaster was ten times greater then the average amount emitted from the west roaster. 

The east roaster also had a lower average flow rate, by around 2,000 dscfm, then the west roaster.

The moisture content in the east roaster stack was greater then that of the west roaster. The average moisture content 

in the east roaster stack was 6.04%, while in the west roaster it was 3.54%. Run #1 of the east roaster exhibited the 

highest moisture content and emissions at 8.71% and 0.0019 gr/dscf respectively. During a December 2009 test the 

east roaster exhibited similar readings, 8.3% moisture and 0.0017gr/dscf. During the January 2010 test, when both 

roasters met the emission limit, the moisture content averaged 3.2% for both roasters. 

Average process parameters for the roaster control system during method 29 testing are displayed in the table below. 

Jerritt is still not providing the temperature of mercury scrubber #2 or the ORP value for mercury scrubber #1. Most 

of the differential pressures across the scrubbers remain well below their set points. Many of the differential pressure 

readings should have triggered deviation alarms.

Thermal 

Unit

Tested 

Production 

(tons/hour)

Permitted 

Throughput 

(tons/hour)

Percent of 

Permitted 

Throughput

Process 

Sample 

Loading 

(ppm)

Mercury Emission Rates (gr/dscf) Average 

Tested 

Hg 

Emissions 

(gr/dscf)

Permitted 

Hg 

Emission 

Rate 

(gr/dscf)

Run #1 Run #2 Run #3

West 

Roaster

68.9 ore

0.99 coal 

90 ore

1.9 coal

76.6% ore

52.1% coal 11.3 1.06x10-4 5.00x10-5 7.13x10-5 7.59x10-5 2.60x10-4

East 

Roaster

69.4 ore

1.65 coal

90 ore

1.9 coal

77.1% ore

86.8% coal 11 1.90x10-3 4.79x10-4 4.57x10-4 9.47x10-4 2.60x10-4
Appendix: Consent Decree Test Data

Page 13 of 15

March 2010

Parameter

East 

Roaster 

Tested

West Roaster 

Tested

Set 

Point

Deviation

Alarm Interlock

Entoleter DP (in. WC) 34.3

Not Tested

25.0 5.0 15.0

SO2 Scrubber DP (in. WC) 2.2 8.0 5.0 --

SO2 Scrubber pH 8.0 8.0 0.2 7.5

HgCl2 Scrubber #1 DP (in. WC) 1.23 8.0 5.0 --

HgCl2 Scrubber #1 pH 6.8 6.9 0.2 7.5

HgCl2 Scrubber #1 ORP 825 25 750

HgCl – Hg scrubber #2 DP (in. WC) -0.6 8.0 5.0 --

HgCl – Hg scrubber #2 pH 6.7 6.9 -- 7.5

HgCl – Hg scrubber #2 

solution temp (°F) 85.0 3 104.0

Tail gas scrubber DP 57.7 4.0 2.0 --

Tail gas scrubber pH 8.0 8.0 0.2 7.0

No excess emissions or exceedances, process upsets, or deviations during testing or laboratory recovery were 

reported. 

Average process parameters for the East Roaster control syst em during Method 29 testing are displayed in the table 

below. Jerritt is still not providing the temperature of mercury scrubber #2 or the ORP value for mercury scrubber 

#1. Most of the differential pressures across the scrubbers remain well below their set points. Many of the 

differential pressure readings should have triggered deviation alarms, although the report states no deviations during 

testing.

Thermal 

Unit

Tested 

Production 

(tons/hour)

Permitted 

Throughput 

(tons/hour)

Percent of 

Permitted 

Throughput

Process 

Sample 

Loading 

(ppm)

Mercury Emission Rates (gr/dscf) Average 

Tested 

Hg 

Emissions 

(gr/dscf)

Permitted 

Hg 

Emission 

Rate 

(gr/dscf)

Run #1 Run #2 Run #3

East 

Roaster

68.0 ore (avg.)

0.93 coal (avg.)

90 ore

1.9 coal

75.6% ore

48.9% coal 9.0 3.44x10-5 3.16x10-5 3.26x10-5 3.29x10-5 2.60x10-5
Appendix: Consent Decree Test Data

Page 14 of 15

April 2010

Parameter

East 

Roaster 

Tested

West 

Roaster 

Tested

Set 

Point

Deviation

Alarm

Interlock

Entoleter DP (in. WC) 58.30 51.20 25 5 15

SO2 Scrubber DP (in. WC) 1.57 2.28 8 5 --

SO2 Scrubber pH 8.02 8.05 8 0.2 7.5

HgCl2 Scrubber DP (in. WC) 2.16 4.56 8 5 --

HgCl2 Scrubber pH 6.70 6.28 6.9 0.2 7.5

HgCl2 Scrubber ORP - - 825 25 750

HgCl – Hg scrubber #2 DP (in. WC) -0.70 3.97 8 5 --

HgCl – Hg scrubber #2 pH 6.40 6.10 6.9 -- 7.5

HgCl – Hg scrubber #2 

solution temp (°F) 120.90 70.47 85 3 104

Tail gas scrubber DP 57.70 1.55 4 2 --

Tail gas scrubber pH 8.00 8.11 8 0.2 7

Of note, the roasters’ mercury emissions had little variability between runs and between the roasters themselves, 

indicating (very) consistent operations of the roaster operations and their mercury emissions.

The consent decree requires a set of operational parameters for the roaster operation. The test report provides 

roaster and scrubber operating parameter values; however, some required in the consent decree are not present, 

while additional non-consent decree required parameters are included. For this test event the HgCL2 scrubber ORP 

was not provided. For three parameters operations appeared out of range: SO2 Scrubber DP, HgCl2 Scrubber DP and 

HgCl – Hg scrubber #2 DP.

Mercury Emission Rates (gr/dscf)

Thermal 

Unit

Tested 

Production 

(tons/hour)

*Permitted 

Throughput 

(tons/hour)

Percent of 

Permitted 

Throughput

Process 

Sample 

Loading 

(ppm)

Run #1 Run #2 Run #3 Average 

Tested Hg 

Emissions 

(gr/dscf)

Permitted 

Hg 

Emission 

Rate 

(gr/dscf)

(gr/dscf) (gr/dscf) (gr/dscf)

East 

Roaster

67.2

67.9

67.2

70

96

97

96

10.7 2.11x10-5 1.40x10-5 1.51x10-5 1.67x10-5 2.6x10-4

West 

Roaster

69.1

68.3

69.4

70

99

98

99

10.0 1.48x10-5 1.64x10-5 1.72x10-5 1.61x10-5 2.6x10-4
Appendix: Consent Decree Test Data

Page 15 of 15

June 2010

Parameter East Roaster 

Tested

West 

Roaster 

Tested

Set 

Point

Deviation

Alarm Interlock

Entoleter DP (in. WC) 59 50.2 25 5 15

SO2 Scrubber DP (in. WC) 1.7 2.7 8 5 --

SO2 Scrubber pH 8.5 8.5 8 0.2 7.5

HgCl2 Scrubber DP (in. WC) 10, 10.1, 15.6 2.7 8 5 --

HgCl2 Scrubber pH 6.9 6.6 6.9 0.2 7.5

HgCl2 Scrubber ORP 825 25 750

HgCl – Hg scrubber #2 DP (in. WC) -0.6, -0.6, 4.2 -0.7 8 5 --

HgCl – Hg scrubber #2 pH 6.8 6.6 6.9 -- 7.5

HgCl – Hg scrubber #2

solution temp (°F) 85 3 104

Tail gas scrubber DP 57.7 2.6 4 2 --

Tail gas scrubber pH 8.5 8.5, 8.5, 7.7 8 0.2 7

Testing was completed at an adequate level of production, and absence of cyclonic flow was verified for both units. 

Mercury emissions from all runs were well below the mercury emission limit established in the consent decree.

Jerritt is still not providing the temperature of mercury scrubber #2 or the ORP value for mercury scrubber #1. 

Several of the differential pressure values are lower than their set points. 

About 45 minutes into run #3 of the west roaster the production data shows that the pH in the tail gas scrubber 

dipped to 2.6. This dropped the average pH for that run to about 7.7, without that 2.6 the average rises to 8.5. This 

dip wasn’t reported as a deviation.

Thermal 

Unit

Tested 

Production 

(tons/hour)

Permitted 

Throughput 

(tons/hour)

Percent of 

Permitted 

Throughput

Process 

Sample 

Loading 

(ppm)

Mercury Emission Rates (gr/dscf) Average 

Tested Hg 

Emissions 

(gr/dscf)

Permitted 

Hg 

Emission 

Rate 

(gr/dscf)

Run #1 Run #2 Run #3

West 

Roaster

78 ore

0.19 coal

90 ore

1.9 coal

86.7%

10% 9.7 2.11x10-5 1.76x10-5 2.19x10-5 2.02x10-5 2.60x10-5

East 

Roaster

78.4 ore

0.17 coal

90 ore

1.9 coal

87.1%

8.9% 10.3 2.65x10-5 2.72x10-5 2.95x10-5 2.77x10-5 2.60x10-5