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

 

 To: Chuck French/RTP/USEPA/US@EPA 

 

 Date: 11/04/2010 06:35 PM 

 

 Subject: Cortez 

 

Chuck,

Let me know if this helps. I attached the stack test report summary sheets and 

our internal stack test reviews for the 2009 tests.

-Rob

See attached files:

Cortez Dec 2009 Results Summary.pdf

Cortez Dec 2009 Source Test Review.doc

Cortez Oct 2009 Results Summary.pdf

Cortez Oct 2009 stack test review .doc

-----Original Message-----

From: Tanya Soleta

Sent: Thursday, November 04, 2010 11:06 AM

To: Patrick Anderson

Subject: FW: Clarification on Cortez test

During the October test of furnace #1 the material mercury concentration averaged 

8ppm and during the December test the material mercury concentration averaged 

1557 ppm. It is unknown what caused the large dip in mercury in the material. 

Previous tests in 2007 and 2008 averaged 4480 and 4250 ppm respectively.

-----Original Message-----

To: Patrick Anderson

Subject: FW: Clarification on Cortez test

In addition, I have included an excerpt from my stack test review dated 03/03/10 

for the December furnace tests:

Operational parameters and work practice standards did not deviate outside of the 

permitted ranges specified for the units in MOPTC AP1041-2220. However, tested 

throughput was well below permitted levels and there is no indication in the test 

report that the differential pressure for the carbon bed was ever monitored or 

recorded during testing. A call was placed to Cortez on 06/02/10 and followed up 

via email requesting whether the carbon bed was operating during testing given 

the significantly lower emissions for the furnaces based on historical data. A 

response was received on 06/07/10 indicating that the carbon bed was on-line 

during testing even though the NDEP was not notified of commencement of 

operations until 02/01/10. It was decided internally to make a note to the file 

as is being done here and to remind the testing company conducting the 2010 tests 

to ensure that all relevant work practice standards are monitored and recorded as 

required in MOPTC AP1041-2220 during the testing event.
Via telephone conversation with Brent Downey, he indicated that the material was 

not retorted, that the carbon bed was on-line during testing, and that the 

Grieve Drying Oven had been used to process the precipitate prior to smelting. 

So, we have two new variables to

consider: (1) anomalously low loading for the October test and (2) the addition 

of the carbon bed to the control train.

As for the PB Tanks, they have not been ducted to the Carbon Kiln and continue to 

passively vent to atmosphere. Any variability in test results is just that, 

random variability, unless they changed their Cherokee Chemical protocol in some 

way as this is the only "control" on the tank emissions. As a final note, per 

phone conversation with Andrew Wilkin this morning (11/04/10), Cortez is 

considering amending their

Phase-2 application and ducting the tanks to their Electro-winning Circuit 

controls and not the Carbon Kiln - stay tuned.

Hi Rob,

Thanks again for providing information on Cortez. However, we have

some additional questions. We need to better understand the new test

data we received from you. Based on the information you sent, the melt furnace 

(S2.002) was tested in October 2009 and December 2009.

Emissions are much lower for the October test, and we don’t know why that is the 

case. We guess that it could be that there was a problem with the new control 

system or the throughput was unusually low during the test (compared to the Dec. 

09 test). Anyway, all we have are the emission rates, we don’t have the test 

reports or any information on how the tests were conducted. We also need to 

understand the situation with the preg & barren tanks. We believe Cortez was 

planning to duct those emissions to the kiln control device (carbon adsorber). 

The 2009 data for the preg & barren tanks are much lower than previously, so 

maybe the

09 data were measured after ducting the emissions to the adsorber.

However, if that were the case, it is unclear how they can still report the preg 

& barren tank emissions separately. To do so, they would have to shut down the 

kiln (or direct the kiln emissions to bypass the control device), while the preg 

& barren tanks were in operation.

Anyway, could you please provide us with more information ASAP (by 11/5, if 

possible) on the control device configurations and process operations during the 

2009 emission tests and any other information that you have that could help us 

better understand the Cortez data.

 Thank You.

 Chuck

(See attached file: Cortez Dec 2009 Results Summary.pdf)(See attached

file: Cortez Dec 2009 Source Test Review.doc)(See attached file: Cortez Oct 2009 

Results Summary.pdf)(See attached file: Cortez Oct 2009 stack test review .doc)

















Nevada Mercury Control Program

SOURCE TEST REVIEW & REPORT

Company Barrick Cortez, Inc. Date 03/30/10

Facility Cortez Mine By: Patrick Anderson

Permit No. MOPTC AP1041-2220 FIN No.: A0001

Testing Firm & 

Lab Company

Horizon Air Measurement 

Services, Inc.

Test 

Dates:

December 15 & 21, 

2009

Systems Tested System 3/TU4.003 and TU4.004: Refinery Induction

Furnaces #1 and #2

Introduction

On August 24, 2009 Barrick Cortez, Inc. submitted to the Nevada Mercury Control Program 

(NMCP) a Test Protocol for the annual mercury testing of Systems 1-6 of MOPTC AP1041-2220. 

Horizon Air Measurement Services, Inc. (Horizon) was contracted to perform the EPA Method 

29 Stack Testing. The majority of testing was completed October 20, 2009. However, the 

original test protocol proposed testing only one of the two existing Refinery Furnaces (TU4.003 

and TU4.004). The rationale for the proposed testing regimen was that the System 3 consists of a 

large furnace (TU4.003) and a small furnace (TU4.004), with the smaller furnace acting as a back 

up which is rarely used. Both AQOP AP1041-2141 and MOPTC AP1041-2220 authorize 

operation of each unit at a throughput rate of 250 pounds per batch, and both permits allow for 

the simultaneous operation of the each individual unit. Since simultaneous operation is allowed 

by the permits, the Nevada Division of Environmental Protection/Bureau of Air Pollution Control 

(NDEP/BAPC) required both furnaces be tested under representative operating conditions. This 

resulted in rescheduling of the furnace tests which were completed on December 15 (TU4.003) 

and 21 (TU4.004), 2009. The final test report was received by the NDEP/BAPC on February 19, 

2010.

Source Test Results

The corresponding emission rate in lbs/hour for TU4.003 was 0.000106 and for TU4.004 

was 0.000131.

Discussion of Test Results

The average cyclonic flow angle for TU4.003 was measured at 5.4 degrees and 2.1 degrees for 

TU4.004, well within the EPA Method 1 acceptable limit of 20 degrees. No sampling or 

operational testing problems were encountered during testing. Operational parameters and work 

practice standards did not deviate outside of the permitted ranges specified for the units in 

Mercury Emission Rates (lbs/hour)

Thermal 

Unit

Tested 

Production

(tons/batch)

Permitted 

Throughput

(tons/batch)

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

Furnace 

#1

TU4.003 0.125 0.3 41.67% 1,557 0.0000109 0.0000049 0.0000075 0.0000078 0.00092

Furnace 

#1

TU4.004 0.1 0.2 50.0% 551 0.0000118 0.000013 0.0000095 0.0000114 0.00092
MOPTC AP1041-2220. However, tested throughput was well below permitted levels and there is 

no indication in the test report that the differential pressure for the carbon bed was ever monitored 

or recorded during testing. A call was placed to Cortez on 06/02/10 and followed up via email 

requesting whether the carbon bed was operating during testing given the significantly lower

emissions for the furnaces based on historical data. A response was received on 06/07/10 

indicating that the carbon bed was on-line during testing even though the NDEP was not notified 

of commencement of operations until 02/01/10. It was decided internally to make a note to the 

file as is being done here and to remind the testing company conducting the 2010 tests to ensure 

that all relevant work practice standards are monitored and recorded as required in MOPTC 

AP1041-2220 during the testing event.

Twelve months of average throughput values from July 2008 through June 2009 were submitted 

for TU4.003 as part of the testing protocol averaging 183.1 lbs/batch with a range of 163.3 –

192.9 lbs/batch. Values were monthly averages and not individual per batch weights, so there is 

no way of telling the monthly range of values over the 12 month time period. No throughput 

history was provided for TU4.004 which is consistent with the infrequent operations of the unit. 

Additionally, the material charge weight during testing of 250 lbs includes flux with the actual 

batch weight for TU4.003 during testing equaling 167 lbs which is closer to the low end of the 12 

month average range. Charge weight for TU4.004 was 200 lbs with an actual batch weight of 

133 lbs.

The table below lists the Phase-2 permitted work practice standards and their measured values 

during testing for TU4.003 and TU4.004.

Work Practice Standard Tested Value Permitted Value

Baghouse Differential Pressure (TU4.003) 0.4 inches H2O 0.0-5.5 inches H2O

Baghouse Differential Pressure (TU4.004) 0.8 inches H2O 0.0-5.5 inches H2O

Carbon Bed Differential Pressure (TU4.003) Not Recorded < 10.0 inches H2O

Carbon Bed Differential Pressure (TU.4004) Not Recorded < 10.0 inches H2O

Isokinetics were verified and found to be within tolerance averaging 103.07% across 

three runs for TU4.003 and 103.02% for TU4.004 (see Attachment #2). Attachment #1 

verifies calculated emission rates as reported in the final stack test report. Both units 

tested under their permitted emissions limit of 0.00092 gr/dscf. However, it should be 

noted that this emissions limit was designed to accommodate both furnaces (TU4.003 & 

TU4.004) and both retorts (TU4.010 & TU4.011) operating simultaneously since they all 

share a common carbon bed prior to exhausting to the atmosphere.

Detailed Recommendations

Specify in future testing protocol response letters that work practice standards must be 

monitored during testing and potentially include a table similar to the one above to ensure 

the testing company is fully aware of what the relevant parameters are.

Ask for per batch weights for twelve months prior to testing to get a better idea of the 

monthly range of values, including charge weights.

Accept test results as submitted.
Reviewer Signature: ____________________________________Date____________

NMCP Supervisor Signature: ____________________________Date____________

Attachment #1 (Mercury Concentration & Calculated Mercury lbs/hour)

Attachment #2 (Isokinetics Calculations)























Nevada Mercury Control Program

SOURCE TEST REVIEW & REPORT

Company Barrick Date 1/11/10

Facility Cortez By: Tanya Soleta

Permit No. 1041-2220 FIN No.: 001

Testing Firm & 

Lab Company

Horizon Test 

Dates:

10/14 through 

10/20/2009

Systems Tested East and West Electrowinning, Furnace #1, Carbon Kiln #2, 

Assay Furnaces, and Pregnant and Barren Tanks

Introduction

On August 24, 2009 Barrick Cortez, Inc. submitted to the Nevada Mercury Control 

Program (NMCP) a Test Protocol for the annual mercury testing of their East and West 

Electrowinning (TU4.001 and TU4.002), Refinery Induction Furnace #1 (TU4.003), 

Carbon Kiln #2 (TU4.006), Assay Furnaces (TU4.007), and Pregnant and Barren Tanks 

(TU4.008 and TU4.009). Horizon Air Measurement Services, Inc. (Horizon) was

contracted to perform the EPA Method 29 Stack Testing. The tests were completed 

October 20, 2009, and the Test Report was received December 15, 2009. Carbon Kiln #1 

had a component failure in March 2009 and was not in operation during the remainder of 

the year. No mercury testing was performed for carbon kiln #1 during 2009. Due to 

power constraints furnaces #1 and #2 cannot be tested simultaneously. NDEP approved 

individual testing of the furnaces during the same test year, and furnace #2 was tested 

December 15, 2009. 

Source Test Results

Discussion of Test Results

Absence of cyclonic flow was verified for all units. All necessary material samples were 

taken; however, the material samples taken for the furnace were analyzed after the 28 day 

holding time for mercury, and this is included in the deviation report. All work practice 

standards were within permitted ranges, and are displayed in the table below. The stack 

flow rate for kiln #2 was higher then the permitted stack parameters. 

Thermal Unit Tested 

Production

Permitted 

Throughput 

Percent of 

Permitted 

Throughput

Process 

Sample 

Loading 

(ppm)

Mercury Emission Rates (lbs/hour) Average 

Tested Hg 

Emissions 

(lbs/hour)

Run #1 Run #2 Run #3

East 

Electrowinning 

(TU4.001) 51 (gal/min) n/a n/a 0.073 4.29x10-5 1.09x10-5 2.68x10-5 2.68x10-5

West 

Electrowinning 

(TU4.002)

32.3 

(gal/min) n/a n/a 0.072 1.49x10-5 1.58x10-5 7.0x10-6 1.25x10-5

Furnace #1 

(TU4.003) 228.3 (lbs) 250 (lbs) 91.3 7.7 2.19x10-5 1.66x10-5 2.57x10-5 2.14x10-5

Carbon Kiln #2 

(TU4.006) 0.67 (tph) 0.81 (tph) 82.7 10.7 2.38x10-5 1.62x10-5 1.03x10-5 1.68x10-5

Assay Furnaces 

(TU4.007) 6.85 (lbs/hr)

44 (lbs/hr)

Protocol6.27 (lbs/hr) 109 10.3 2.20x10-5 5.78x10-5 9.77x10-6 2.99x10-5

Preg and Barren 

Tank (TU4.008 

& TU4.009)

48.8 

(gal/min) n/a n/a 0.031 9.56x10-6 7.17x10-6 7.36x10-6 8.03x10-6
Work Practice Tested Value Permitted Value

Furnace Baghouse Differential Pressure 0.8 0.0-5.5 inches H2O

Kiln Wet Scrubber Flow Rate 38.22 ≥ 27 gpm

Kiln Wet Scrubber Pressure Drop 14.02 ≥ 7 inches H2O

Assay Furnace Baghouse Differential Pressure 3.4 1.5-6.0 inches H2O

The mercury concentrations and calculated mercury emission rates were within 

acceptable limits (see Attachment #1). The emission rates in lb/hr for the last three years 

are displayed in the table below. Furnace #1 showed a drastic reduction in mercury 

emissions from previous years. This reduction was due to emissions being vented through 

a recently installed carbon bed. The furnace also had a very low material mercury 

concentration when compared to previous years. In 2007 and 2008 the mercury material 

concentration was 4480ppm and 4250ppm respectively, while in 2009 it averaged 

7.7ppm. The large difference between emissions from the pregnant and barren tanks may 

be due to the difference in throughput, which was 102 gal/min in 2008 and only 48 

gal/min in 2009.

Unit 2007 2008 2009

East Electrowinning 1.3x10-4 6.75x10-5 2.68x10-5

West Electrowinning 1.17x10-4 2.17x10-5 1.25x10-5

Furnace #1 0.2694 0.1168 2.14x10-5

Carbon Kiln #2 3.67x10-3 2.13x10-5 1.68x10-5

Assay Furnaces 1.32x10-4 1.34x10-4 2.99x10-5

Preg and Barren Tank n/a 3.15x10-4 8.03x10-6

Isokinetics were calculated and were within acceptable limits (see Attachment #2).

However, run #1 of the pregnant and barren tanks had a calculated isokinetic rate of 

89.98%. This is outside the 90%-110% range, but this difference could be attributed to 

rounding. It’s interesting to note that in 2008 run #1 of the pregnant and barren tanks had 

an isokinetic rate of 110.28%. 

Detailed Recommendations

Although the pregnant and barren tanks showed an isokinetic rate outside the 100% +/-

10%, as required by the protocol, this test should be considered valid. An email was sent 

to Brent Downey on 1/11/2010 advising Cortez to evaluate the stack characteristics of the 

pregnant and barren tanks to ensure future tests would achieve isokinetics.

Reviewer Signature: ____________________________________Date____________

NMCP Supervisor Signature: ____________________________Date____________

Attachment #1 (Mercury Concentration & Calculated Mercury lbs/hour)

Attachment #2 (Isokinetics Calculations)