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 t ests.

- 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 throughp ut 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 n ot 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 monito red 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 duct ed 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,

Than ks 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, In c. Test

Dates: December 15 & 21

, 20 09 Systems Tested System 3 /TU4.00 3 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 th e 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 test ing w as completed October 20, 2009 . However, t he original test p rotocol propose d testing only one of the two existing Refinery F urnaces (TU4.003 and TU4.004). The rationale for th e proposed testing regimen was that the System 3 consist s of a large furnace (TU4.003) and a small furnace (TU4.004), with the smaller furna ce acting as a back

up which is rarely used. Both AQOP AP 1041

- 2141 and MOPTC AP 1041

- 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 (TU4.00 3 ) and 21 (TU4.00 4 ), 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

.

Discussi on 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 testi ng. 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/ batc h ) 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 0.000 0109 0.0000 049 0.000 0075 0.00 0 0 078 0.00092

Furnace

#1

TU4.004 0.1 0.2 50.0% 551 0.000 0118 0.000 013 0.00 00 0 95 0.0 0 00 114 0.00092MOPTC 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 interna lly 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

.

Twel ve 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 dur ing 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.

T he 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 H 2 O 0.0

- 5.5 inches H 2 O Baghouse Differential Pressure (TU4.004) 0.8 inches H 2 O 0.0

- 5.5 inches H 2 O Carbon Bed Differential Pressure (TU4.003) Not Recorded < 10.0 inches H 2 O Carbon Bed Differential Pressure (TU.4004) Not Recorded < 10.0 inches H 2 O



### Isokinetics w ere verified and found to be within tolerance averaging 10 3.07 % 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 perm itted 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 carbo n 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 Signatu re: ____________________________ 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 Fu rnace #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

Decem ber 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

Eas t 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 1.62 x10 - 5 1.03x10 - 5 1.68x10 - 5

Assay Furnaces (TU4.007) 6.85 (lbs/hr) 44 (lbs/hr)

Protocol

6.27 (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 H 2 

### O

Kiln Wet Scrubber Flow Rate 38.22 ≥ 27 gpm

Kiln Wet Scrubber Pr essure Drop 14.02 ≥ 7 inches H 2 

### O Assay Furnace Baghouse Differential Pressure 3.4 1.5

- 6.0 inches H 2 

### O

The mercury concentration s and calculated mer cury 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 recentl y installed carbon bed

. The furnace also had a very low m aterial 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 t anks may be due to the difference in throughpu t, 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, ru n #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 require d 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 Signatu re: ______

______________________ Date____________

Attachment #1 (Mercury Concentration & Calculated Mercury lbs/hour) Attachment #2 (Isokinetics Calculations)