# Meteorological and Hydrogen Cyanide (HCN) Fence Line Monitoring Report

B

ARRICK 

# C ORTEZ


# , I NC



# .

P ROJECT 

## 59-52-10 J ANUARY 

## 2010Draft_Cortez Hcn Monitoring Report_R2.Docx 

### ii 

# CONTENTS Page

1.0 INTRODUCTION .............................................................................................................. ........................................... 1 1.1 HCN Monitor and Meteorological Station Locations .......................................................................... ..................... 1 1.2 HCN Monitoring System Description ......................................................................................... ............................. 6 1.3 Data Recovery ............................................................................................................. .......................................... 7 1.4 Quality Control ........................................................................................................... ............................................. 7

2.0 METEOROLOGY AT THE PIPELINE STATION ....................................................................................... ................ 8

2.1 Winds ..................................................................................................................... ................................................ 8 2.2 Temperature, Relative Humidity, and Barometric Pressure ................................................................... ............ 11

3.0 HCN MONITOR ............................................................................................................... ......................................... 12

3.1 Winds ..................................................................................................................... .............................................. 12 3.2 Temperature, Relative Humidity, and Barometric Pressure ................................................................... ............ 12 3.3 HCN Concentration ......................................................................................................... ..................................... 13

4.0 DATA ANALYSI S ............................................................................................................. ........................................ 14



## Tables

Table 1: Sensor Locations .................................................................................................... ........................................... 6 Table 2: Data Recovery ....................................................................................................... ............................................ 7 Table 3: Frequency of Hourly Averaged Winds by Direction and Speed ........................................................... .............. 9 Table 4: Frequency of Hourly Averaged Winds by Direction and Stability ....................................................... ................ 9 Table 5: Temperature, Relative Humidity, and Barometric Pressure ............................................................. ................ 11 Table 6: Temperature, Relative Humidity, and Barometric Pressure ............................................................. ................ 12
Table 7: HCN Concentration ................................................................................................... ....................................... 13 Table 8: Measured HCN Concentration Analysis ................................................................................. .......................... 14



## Figures Figure 1: HCN Monitoring Site (small scale) .................................................................................. .................................. 2 Figure 2: HCN Monitoring Site (large scale) .................................................................................. .................................. 3 Figure 3: Potential HCN Sources .............................................................................................. ....................................... 4 Figure 4: Potential HCN Sources, Mill Area ................................................................................... .................................. 5 Figure 5: Wind Frequency Distribution ........................................................................................ ................................... 10 Figure 6: Measured HCN Concentration Analysis ................................................................................ ......................... 15 Figure 7: Wind frequency for December 24, 2009 (Lowest Concentration Day) .................................................... ........ 16 Figure 8: Wind frequency for December 21, 2009 (Highest Concentration Day) ................................................... ........ 16



## Appendices
Appendix A: Hourly Meteorological Data Appendix B: HCN Data Appendix C: Site Check Forms, Audits, and Calibration Appendix D: Hydrogen Cyanide (HCN) Fence Line Monitoring PlansDraft_Cortez Hcn Monitoring Report_R2.Docx 

### 1 

## SECTION 1 

# INTRODUCTION

This report summarizes the meteorological and hydrogen cyanide (HCN) data collected at the Barrick Cortez, Inc. (Cortez) Pipeline meteorological station and Cortez HCN monitor through December 24, 2009. The HCN monitor station became operational on November 29, 2009, at 6:00 p.m. and the first 24-hour HCN sample was take n on November 30, 2009. The HCN monitoring equipment and sampling procedures followed Cortez’s Site-Specific Hydrogen Cyanide (HCN) Fence Line Monitoring Plan , approved by EPA on October 29, 2009, and the general Hydrogen Cyanide (HCN) Fence Line Monitoring Plan , approved by EPA on October 9, 2009. The meteorological sampling procedures were perf ormed in accordance with the U. S. EPA Quality Assurance Handbook of Air Pollution Measurement Sy stems Volume IV - Meteorological Measurements (EPA-600/R94-038D), March 1995.

Cortez operates a gold mining facility located a pproximately 38 miles south of Interstate 80, Exit #261 (Beowawe exit) on State Route 306, in La nder and Eureka Counties, Nevada. The facility operates both open-pit and underground mines. Gold recovery operations include: crushing, milling, heap and tank leaching, carbon adsorp tion, stripping and regeneration, electrowinning, and smelting. The leach solutions used in the go ld recovery processes contain cyanide. These solutions have the potential for low levels of HC N formation and emission to the atmosphere. To
assess the ambient concentrations of HCN emissi ons, Cortez installed and continues to operate an HCN monitor downwind of the potential HCN sources at the boundary of the Cortez operations area.



# 1.1 HCN Monitor and Meteorol ogical Station Locations

Aerial photos and shaded relief maps are provided in Figures 1 through 4. Figure 1 provides an aerial photo of the mine site, the northeastern operations boundary, th e HCN monitor location, and the nearest residences to the Cortez operations boundary. Figure 2 provides a shaded relief map of the entire Cortez claims boundary and neig hboring towns. This figure shows the location of the Pipeline meteorological station and the HCN monitor.

Figures 3 and 4 highlight the potential sources of HCN emissions at Cortez. These sources include a tailings impoundment, two leach pads (Area 28 and Area 30), and stacks and tanks at the mill area. A closer view of the mill area HCN sources is shown in Figure 4.

# [West Heap Leach East Heap Leach AREA 28

AREA 30 Tailings Storage Impoundment Barrick Owned Ranch Houses

HCN Monitoring Site

1 5 4

7 3 6 2

8 5

8 9 12

13 8 7

11 30

31 19

18 25 20

27

32 18

28 26 24

33 32 34 15

22 21 16

35 29 17 13

36 17

23 14

17 16 15 14 10 20

29

17 9 8

6 11 12

7 10

19 18

30 7

31

24 23 22 21 18

20 19 20 9

16

19 21 

### T28N:R47E

T27N:R47E T28N:R48E

T27N:R48E 525000

525000 530000

530000 535000

535000445000044500004455000445500044600004460000

Datum: NAD83 UTM Zone 11N Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Com pliance\MXD\HCN_Site_01122010_Fig1.mxd 

# · Barrick Cortez Mines Lander & Eureka Counties, Nevada 

# HCN Monitoring Site Figure 1

January 12, 2010

0 5,000 10,000 15,000 20,000 Feet 

### 0 1,000 2,000 3,000 4,000 5,000 6,000 Meters 

## Cortez Operations Area
Dean Ranch (private land) Potential HCN Source Areas



# [HCN Monitoring Site Looking Northeast SITE_ID EAST NORTH AQM-001 532667 4457396

## ! (

! ( ! (

! (

 

#  \ 

# [  HCN Monitoring Site Barrick Owned Ranch Houses 

# 

  80



# 278 

# 305 

# 306 

# 766EUREKA CO.LANDER CO. 

### ELKO CO.

HUMBOLDT

Met Tower (Pipeline) 

## Carlin

Beowawe Battle Mountain

Crescent Valley 500000

500000 520000

520000 540000

540000 560000

560000 580000

5800004440000444000044600004460000448000044800004500000450000045200004520000

Datum: NAD83 UTM Zone 11N Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Com pliance\MXD\PotentialHCN01122010_Fig2.mxd 

# · Barrick Cortez Mines Lander & Eureka Counties, Nevada 

# HCN Monitoring Site Figure 2

January 12, 2010 0 5 10 15 20 25 Miles



### 0 10 20 30 40 Kilometers 

## Cortez Operations Area
Cortez Claims Boundary (AOI)
Dean Ranch (private land)

Potential HCN Source Areas

 

#  \ Climate Station 

# [  HCN Monitoring Site

## AREA 28

AREA 30 Tailings Storage Impoundment Mill Area 522000

522000 524000

524000 526000

526000 528000

52800044520004452000445400044540004456000445600044580004458000

Datum: NAD83 UTM Zone 11N Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Com pliance\MXD\PotentialHCN102009_Fig3.mxd 

# · Barrick Cortez Mines Lander & Eureka Counties, Nevada


# Potential HCN Sources Figure 3

October 08, 2009 0 2,000 4,000 6,000 8,000 10,000 Feet



### 0 400 800 1,200 1,600 2,000 2,400 2,800 3,200 Meters 

## Legend

Cortez Operations Area

Potential HCN Source Areas

### CIL Tanks CIC Tanks

Preg / Barren Tank

E. Cell Stack W. Cell Stack 523800

523800 524000

524000 524200

5242004456800445680044570004457000

Datum: NAD83 UTM Zone 11N Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Com pliance\MXD\PotentialHCNmill102009_Fig4.mxd 

# · Barrick Cortez Mines Lander & Eureka Counties, Nevada 

# Potential HCN Sources, Mill Area

Figure 4

October 08, 2009 0 200 400 600 Feet



### 0 40 80 120 160 200 Meters 

## Legend

Potential HCN Source AreasDraft_Cortez Hcn Monitoring Report_R2.Docx 

### 6 

# 1.2 HCN Monitoring System Description

The HCN monitoring system consists of a data logger connected to a low-flow pump which is connected through sorbent tubes to an ambient air inlet. The sorbent tubes capture any HCN in the ambient air and are sent to the ALS Laboratory Group in Salt Lake City, Utah for analysis. The lab analysis is based on NIOSH Method 6010. The sampling schedule follows a 1-in-3 day calendar and will continue for a total sampling period of two months.

During a run day, all meteorological parameters are collected at more frequent intervals and time-averaged into 15-minute values. Wind sp eed and wind direction are collected at the Pipeline meteorological statio n. Ambient temperature, relative humidity, and barometric pressure as well as flow rate through the so rbent tubes are collected at the HCN monitor. Ambient temperature, relative humidity, and ba rometric pressure are also collected at the Pipeline meteorological station and serve as a quality check for the HCN monitor data. The parameters collected are shown in Table 1.

The measurement height of the inlet is two meters. The height of the wind instruments is 10 meters. All other parameters are measured at two meters.

Table 1: Sensor Locations (meters above the ground)



## Parameter Height Wind speed* 10.0
Wind direction* 10.0 Ambient temperature 2.0 Relative humidity 2.0 Barometric pressure 2.0 Sampler Flow 2.0
*Wind data are from the Pipeline meteorological station.



## The 15-minute averaged data from the Pipeline me teorological station are sent electronically to Air Sciences Inc. (Air Sciences) where they are transferred into a database. The meteorological data from the HCN monitor are recorded by the onsite digital Data Acquisition System (DAS) equipped with cellular internet for data transfer . The parameters are digitally processed by the DAS into 15-minute averages. The 15-minute averag es are transmitted to Air Sciences for quality assurance checks and population into the data base. The 15-minute averages from both the Pipeline meteorological station and the HCN monitor are used as input to the Air Sciences’ database for the calculation of one-hour averages.Draft_Cortez Hcn Monitoring Report_R2.Docx 

### 7 

# 1.3 Data Recovery

Data recovery rates for all paramete rs are presented in Table 2.

The meteorological data recovery rate was 10 0 percent for all parameters at the Pipeline meteorological station and 85.2 percent at the HCN monitor. The lower data recovery rate at the HCN monitor was due to the site being down for maintenance and data logger program updates. The data recovery rates at the Pipeline meteorological station are above the recommended rate of 90 percent for all meteorological parameters.

The data recovery rate for the HCN sorbent tubes was 100 percent, which is above the recommended rate of 75 percent.

Table 2: Data Recovery November 30, 2009 - December 24, 2009 (percent)



## Recorded Recommended

Parameter Observations Recovery Rate Recovery Rate Pipeline Station Wind speed 600 100.0 90
Wind direction 600 100.0 90 Ambient temperature 600 100.0 90 Relative humidity 600 100.0 90 Barometric pressure 600 100.0 90
HCN Station Ambient temperature 216 85.2 90 Relative humidity 216 85.2 90 Barometric pressure 216 85.2 90
HCN concentration 9 100.0 75



# 1.4 Quality Control

The primary meteorological quality objectives are based on U.S. EPA guideline documents (EPA454/4-87-007, Section 6.1.1, Ambient Monitoring Guidelines for Prevention of Significant Deterioration [PSD] and EPA-454/R-99-005, February 2000, Table 5-1., Meteorological Monitoring Guidance for Regulatory Modeling App lications). The quality control objectives for the HCN monitor can be found in Appendix D.Draft_Cortez Hcn Monitoring Report_R2.Docx 

### 8 

## SECTION 2 

# METEOROLOGY AT THE PIPELINE STATION

The instantaneous wind speed, wind direction, te mperature, relative humidity, and barometric pressure data collected at the Pipeline meteorolog ical station during the monitored period were processed into hourly averages. Appendix A presents the hourly averages for each parameter in SAROAD (Storage And Retrieval Of Aerometric Data) format. A summary of this data for each parameter is shown in the following sections.



# 2.1 Winds

Hourly averaged winds measured at the site during the sampling period are summarized in Table 3 as frequency distributions of winds by di rection and speed. The data period contains 25 days (600 hours) of complete wind information.

Figure 5 shows the distribution of hourly av eraged winds by direction and speed for the sampling period. The mean wind speed for the period was 1.9 m/s (4.3 mph). The winds were predominately from the southwest to the west. The winds ranged from moderate to brisk this period. A breakdown of the wind speed profile this period yields the following: There were 6.2 percent calm wind speeds (<0.447 m/s), 52.3 pe rcent of the winds were between 0.5 m/s (1.1 mph) and 1.5 m/s (3.4 mph), 37.7 percent of the winds were between 1.5 m/s and 5 m/s (11.2 mph), and 3.8 percent of the wind sp eeds were greater than 5 m/s.

Table 4 shows a frequency distribution of hourly av eraged winds by directio n and stability class. Stability classes A, B, and C indicate low-speed daytime winds, which are categorized as unstable or high-dispersion-potential winds with class A being the least stable. Stability classes E and Findicate the frequency of low-speed nighttime winds, which are categorized as stable or lowdispersion-potential winds with class E being the least stable. The D stability class is a mixture of daytime and nighttime winds, generally at higher sp eeds. This class is also referred to as neutral stability.

The lower-speed daytime winds (classes A, B, and C) made up 26.3 percent of the total winds and were predominately from the north-northeast to the east-northeast. The lower-speed nighttime winds (classes E and F) constituted 44.6 percent of the total winds and were predominately from the southwest to the north. The higher-speed wi nds (class D) comprised 25.7 percent of the total winds and were predominately from the southwest to the west-southwest with a secondary peak
from the north-northeast to the northeast.Draft_Cortez Hcn Monitoring Report_R2.Docx 

### 9 Table 3: Frequency of Hourly Averaged Winds by Direction and Speed November 30, 2009 - December 24, 2009 (percent of occurrence)



## Calm (< 0.447 m/s) = 6.2% Mean wind speed = 1.9 m/s Data presented as direction from which wind is blowing.

Table 4: Frequency of Hourly Averag ed Winds by Direction and Stability November 30, 2009 - December 24, 2009 (percent of occurrence) Mean

Direction 0.5 <1.5 1.5 <3 3 <5 5 <7 7 <10 >=10 All Speed

N 4.0 0.7 0.3 0.2 0.0 0.0 5.2 1.4

NNE 4.5 1.8 1.2 0.2 0.0 0.0 7.7 1.8

NE 4.2 2.3 1.5 0.7 0.0 0.0 8.7 2.1

ENE 3.7 2.2 0.3 0.2 0.0 0.0 6.3 1.5

E 3.0 0.8 0.3 0.0 0.0 0.0 4.2 1.2

ESE 1.7 0.0 0.0 0.0 0.0 0.0 1.7 0.7

SE 1.8 0.0 0.0 0.0 0.0 0.0 1.8 0.8

SSE 3.0 0.7 0.0 0.0 0.0 0.0 3.7 1.1

S 2.2 1.0 0.5 0.0 0.0 0.0 3.7 1.7

SSW 2.0 1.5 1.0 0.0 0.0 0.0 4.5 1.9

SW 2.8 2.5 3.5 1.7 0.2 0.0 10.7 3.0

WSW 1.7 3.0 3.3 0.3 0.2 0.0 8.5 3.0

W 4.8 2.8 3.2 0.0 0.0 0.0 10.8 2.1

WNW 4.2 1.2 0.2 0.0 0.0 0.0 5.5 1.1

NW 4.2 0.5 0.2 0.0 0.0 0.0 4.8 1.2

NNW 4.7 1.2 0.0 0.2 0.2 0.0 6.2 1.4

All 52.3 22.2 15.5 3.3 0.5 0.0 93.8 1.9 Speed Class Intervals (m/s)



### Direction A B C D E F All

N 0.3 0.5 0.5 1.0 0.8 2.3 5.5

NNE 0.7 1.3 1.0 2.2 0.8 1.7 7.7

NE 0.5 1.5 1.5 3.3 1.2 1.0 9.0

ENE 0.5 1.0 2.2 1.2 0.3 1.7 6.8

E 0.5 1.0 0.7 1.3 0.7 0.3 4.5

ESE 0.2 0.5 0.5 0.3 0.5 0.3 2.3

SE 0.2 0.2 0.3 0.2 0.5 0.7 2.0

SSE 0.3 0.3 0.3 0.5 1.0 1.5 4.0

S 0.2 0.2 0.0 1.0 0.5 1.5 3.3

SSW 0.2 0.3 0.7 0.8 0.7 1.8 4.5

SW 0.2 0.5 1.0 5.3 1.8 2.2 11.0

WSW 0.0 0.5 0.8 4.7 1.3 1.2 8.5

W 0.2 0.5 1.2 2.0 3.7 3.0 10.5

WNW 0.2 0.3 0.5 0.5 2.7 1.5 5.7

NW 0.3 0.2 0.5 0.5 0.7 2.7 4.8

NNW 0.0 0.3 1.2 0.8 1.2 3.0 6.5

All 4.3 9.2 12.8 25.7 18.3 26.3 96.7 Stability ClassDraft_Cortez Hcn Monitoring Report_R2.Docx 

### 10 Figure 5: Wind Frequency Distribution

2%

4%

6%

8%

10%

12%

14%

16%

18%

20% N

NNE

NE

ENE

E

ESE

SE

SSE
S SSW SW WSW W WNW NW NNW

0.5 1 2 4 8 m/s

15-Minute Met Data Wind Frequency Distribution: 11/30/09 - 12/24/09 Calm = 328 Missing = 0 Number of non-calm/missing = 2,072Draft_Cortez Hcn Monitoring Report_R2.Docx 

### 11 

# 2.2 Temperature, Relative Humi dity, and Barometric Pressure

The temperature mean and extremes for the samp ling period are presented in Table 5. The average 2-meter temperature for the period was -4.9 ° C (23.2 ° F). The maximum hourly averaged 2-meter temperature was 9.1 ° C (48.4 ° F) and occurred on the afternoon of November 30, 2009. The minimum hourly averaged 2-meter temperature was -27.0 ° C (-16.6 ° F) and occurred on the morning of December 9, 2009.

The relative humidity mean and extremes for the sampling period are presented in Table 5. The average relative humidity for the period was 72 percent. The minimum hourly average was 10 percent and the maximum was 92 percent.

Barometric pressure data collected during the sa mpling period are summarized in Table 5. The average barometric pressure for the period was 637 mmHg. The maximum hourly averaged barometric pressure for the period was 644 mmHg and occurred for two consecutive hours on December 17, 2009, beginning at 9:00 a.m., fo r two consecutive hours on December 23, 2009, beginning at 11:00 p.m., and again for thirt een consecutive hours on December 24, 2009, beginning at 1:00 a.m. The minimum hourly averaged barometric pressure for the period was 624 mmHg and occurred for seven consecutive hours on December 7, 2009, beginning at 1:00 p.m.

Table 5: Temperature, Relative Humidity, and Barometric Pressure November 30, 2009 - December 24, 2009



## Parameter Temperature ( ° C) 

## Relative Humidity (%) Barometric
Pressure (mmHg) Avg. -4.9 72 637
Max 9.1 92 644
Min -27.0 10 624Draft_Cortez Hcn Monitoring Report_R2.Docx 

### 12 

## SECTION 3 

# HCN MONITOR

The instantaneous temperature, relative humidity, and barometric pressure data collected at the HCN monitor on each run day during the monitored period were processed into hourly averages. Appendix A presents the hourly averages for each parameter in SAROAD format. A summary of this data for each parameter is shown in the following sections.



# 3.1 Winds

There was no wind data collected at the HCN monitor, see Section 2.1 above for wind data.


# 3.2 Temperature, Relative Humi dity, and Barometric Pressure

The temperature mean and extremes for the samp ling period are presented in Table 6. The average 2-meter temperature for the period was -11.2 ° C (11.8 ° F). The maximum hourly averaged 2-meter temperature was 6.8 ° C (44.2 ° F) and occurred on the afternoon of November 30, 2009. The minimum hourly averaged 2-meter temperature was -34.8 ° C (-30.6 ° F) and occurred on the morning of December 9, 2009.

The relative humidity mean and extremes for the sampling period are presented in Table 6. The average relative humidity for the period was 77 percent. The minimum hourly average was 28 percent and the maximum was 99 percent.

Barometric pressure data collected during the sa mpling period are summarized in Table 6. The average barometric pressure for the period was 655 mmHg. The maximum hourly averaged barometric pressure for the period was 660 mmHg and occurred on December 24, 2009, at 3:00 a.m., and again for six consecutive hours on Dece mber 24, 2009, beginning at 6:00 a.m. The minimum hourly averaged barome tric pressure for the period was 646 mmHg and occurred for seven consecutive hours on December 6, 2009, begi nning at 1:00 p.m., and for one hour at 9:00 p.m., and again for four consecutive hours on December 12, 2009, beginning at 9:00 p.m.

Table 6: Temperature, Relative Humidity, and Barometric Pressure November 30, 2009 - December 24, 2009



## Parameter Temperature ( ° C) 

## Relative Humidity (%) Barometric
Pressure (mmHg) Avg. -11.2 77 655
Max. 6.8 99 660
Min. -34.8 28 646Draft_Cortez Hcn Monitoring Report_R2.Docx 

### 13 

# 3.3 HCN Concentration

The HCN concentration data collected during the sampling period are summarized in Table 7. The average standard HCN concentration was 0.54 ppb. The minimum standard HCN concentration for the period was below the detect ion level of 0.21 μg/sample (which equates to 0.07 ppb given the sample volume) and occurred on December 24, 2009. The maximum standard HCN concentration for the period was 0.87 ppb and occurred on December 21, 2009. All HCN concentrations were below the EPA reference concentration of 2.8 ppb.

Table 7: HCN Concentration November 30, 2009 - December 24, 2009 (ppb)



## Run Day* Actual
Concentration Standard
Concentration 11/30/09 0.56 0.58 12/03/09 0.30 0.30 12/06/09 0.30 0.31 12/09/09 0.57 0.55 12/12/09 0.60 0.63 12/15/09 0.54 0.57 12/18/09 0.50 0.52 12/21/09 0.86 0.87 12/24/09 <0.07 ^ 

## <0.07 ^ 

## Average 0.53 0.54

*Start time = 0:00:02; Stop time = 0:00:00.

^ 

### Below Detection Level of 0.21 μg/sample (equates to 0.07 ppb for 12/24/2009 sample).Draft_Cortez Hcn Monitoring Report_R2.Docx 

### 14 

## SECTION 4 

# DATA ANALYSIS

Based on the data collected from the first four we eks of monitoring, an anal ysis of wind direction and measured HCN concentration was conducted. As shown in Figures 1 and 2, winds from

239 ° through 274 ° (approximately southwest through west) blow from the potential HCN sources at the Cortez mine towards to the HCN monitor. The percent of winds blowing within this range of directions on each sample day is shown in Table 8 and Figure 6.

As shown by Table 8 and Figure 6, there doesn’t appear to be a correlation between wind
direction and measured HCN concentration. On both the highest and lowest HCN concentration days, the winds blew from the potential HCN sour ces towards the monitor only four percent of
the time. On the second lowest concentratio n day, the winds blew from the potential HCN sources towards the monitor 25 percent of the ti me, which is the highest percent wind frequency of any of the sample days.

Table 8 also shows that there doesn’t appear to be a correlation between wind speed and
measured HCN concentration. The lowest and highest HCN concentration days had the lowest and second lowest average wind speed, respectively.

Table 8: Measured HCN Concentration Analysis November 30, 2009 - December 24, 2009



## Concentration
Standard Winds Blowing from HCN
Sources towards Monitor Average Wind Speed Run Day (ppb) No. of Hours Percent (m/s) 11/30/09 0.58 5 21 1.5 12/03/09 0.30 6 25 1.6 12/06/09 0.31 3 13 2.0 12/09/09 0.55 4 17 0.9 12/12/09 0.63 3 13 1.9 12/15/09 0.57 5 21 2.5 12/18/09 0.52 5 21 1.3 12/21/09 0.87 1 4 0.9 12/24/09 <0.07 ^ 

## 1 4 0.7 Average 0.54

^ 

### Below Detection Level of 0.21 μg/sample (equates to 0.07 ppb for 12/24/2009 sample).Draft_Cortez Hcn Monitoring Report_R2.Docx 

### 15 Figure 6: Measured HCN Concentration Analysis



## Figures 7 and 8 summarize the 24-hour wind dire ction (the direction from which the wind is blowing) and wind speed for the lowest and hi ghest HCN concentration days. The lowest HCN
concentration was measured on December 24 , 2009. The highest HCN concentration was measured on December 21, 2009. The winds were predominately from the north to the northeast on the lowest concentration day and from the north-northwest to the north-northeast on the highest concentration day. 0 5 10 15 20 25 30

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1StandardConcentration(ppb)PercentofWinds(%)



## Run Day Standard Concentration (ppb) Percent of Winds towards MonitorDraft_Cortez Hcn Monitoring Report_R2.Docx 

### 16 2%

4%

6%

8%

10%

12%

14%

16%

18%

20% N

NNE

NE

ENE

E

ESE

SE

SSE
S SSW SW WSW W WNW NW NNW

0.5 1 2 4 8 m/s

15-Minute Met Data Wind Frequency Distribution: 12/24/2009 Calm = 33 Missing = 0 Number of non-calm/missing = 63 

### Figure 7: Wind frequency for December 24, 2009 (Lowest Concentration Day)

Figure 8: Wind frequency for December 21, 2009 (Highest Concentration Day)

2%

4%

6%

8%

10%

12%

14%

16%

18%

20% N

NNE

NE

ENE

E

ESE

SE

SSE
S SSW SW WSW W WNW NW NNW

0.5 1 2 4 8 m/s

15-Minute Met Data Wind Frequency Distribution: 12/21/2009 Calm = 17 Missing = 0 Number of non-calm/missing = 79

# APPENDIX A 

# Hourly Meteorological DataDay 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Avg Max Min11/30/2009 0.8 0.5 1.4 2.1 1.3 0.6 0.5 0.4 0.4 1.0 0.7 1.3 0.8 0.9 1.7 2.0 1.4 3.5 4.3 3.8 3.4 1.4 1.5 1.2 1.5 4.3 0.412/1/2009 1.7 1.3 0.6 0.5 0.7 0.7 0.9 0.7 0.8 2.5 2.5 1.2 2.4 3.5 3.0 2.3 2.6 3.0 3.9 2.9 2.2 0.7 0.6 0.8 1.7 3.9 0.512/2/2009 0.7 0.8 0.4 0.9 0.7 0.7 0.4 0.7 0.8 0.7 1.3 1.5 2.2 2.8 2.3 2.1 1.0 3.5 3.9 2.0 1.8 1.9 1.2 2.1 1.5 3.9 0.412/3/2009 0.7 0.6 0.6 2.2 1.2 0.6 0.8 0.3 0.6 0.9 0.8 1.1 1.9 2.1 1.7 2.2 1.2 3.6 3.8 4.1 2.9 3.2 1.1 0.5 1.6 4.1 0.312/4/2009 0.5 0.6 1.2 0.5 0.8 1.0 1.0 1.5 1.4 1.5 1.1 2.6 1.5 2.3 2.1 2.9 3.6 3.2 3.5 5.1 6.3 5.9 4.4 5.4 2.5 6.3 0.512/5/2009 5.4 4.7 2.1 2.8 6.1 2.9 2.0 2.8 3.2 4.6 4.2 6.1 5.7 7.2 6.3 4.7 3.1 3.2 1.5 1.0 1.5 2.3 3.2 3.3 3.8 7.2 1.012/6/2009 3.8 3.6 3.0 1.1 0.7 1.1 1.6 0.6 1.0 1.7 1.4 1.1 1.5 1.4 1.7 2.4 2.0 1.0 2.9 2.9 3.6 3.5 3.1 2.2 2.0 3.8 0.612/7/2009 3.5 3.1 1.4 1.4 1.7 2.3 1.8 1.4 2.8 3.2 3.3 4.0 4.6 4.1 2.9 2.5 2.7 1.2 3.0 3.0 3.3 2.7 1.3 1.8 2.6 4.6 1.212/8/2009 4.3 3.9 1.5 1.4 1.3 1.2 0.9 0.9 1.1 0.6 0.2 0.3 0.6 1.0 1.4 1.2 0.9 4.0 1.2 0.8 1.1 0.7 0.9 0.9 1.3 4.3 0.212/9/2009 0.9 1.6 1.7 1.3 0.8 0.6 0.5 0.8 0.6 0.5 0.8 0.7 0.5 0.5 0.7 0.7 1.2 1.5 0.3 0.6 0.7 1.2 1.1 0.6 0.9 1.7 0.312/10/2009 0.4 0.8 0.5 0.1 0.3 0.6 0.2 0.5 0.6 0.6 0.5 0.7 1.0 0.6 0.5 0.2 0.5 0.5 0.3 0.5 0.6 0.5 0.3 1.2 0.5 1.2 0.112/11/2009 0.6 0.7 0.6 0.4 0.4 0.5 0.5 0.6 0.8 0.5 0.6 0.5 0.8 0.7 0.5 0.6 0.6 0.4 0.8 0.6 0.5 0.7 1.3 1.0 0.6 1.3 0.412/12/2009 0.8 1.0 1.1 2.6 3.1 1.4 2.3 2.9 3.3 1.6 1.1 0.6 1.3 2.4 2.0 2.5 2.7 2.2 3.2 3.1 2.9 0.9 0.0 0.0 1.9 3.3 0.012/13/2009 0.0 1.0 3.3 4.1 7.1 2.7 3.6 3.8 3.8 8.8 6.9 6.3 6.2 5.9 5.6 4.6 3.5 2.8 2.6 2.6 4.6 4.2 4.8 5.0 4.3 8.8 0.012/14/2009 4.6 4.8 4.1 4.9 4.4 4.6 3.2 0.8 1.3 1.7 1.8 1.6 3.1 3.0 2.4 0.4 1.4 3.3 2.4 2.3 1.2 1.3 1.5 1.4 2.6 4.9 0.412/15/2009 4.3 2.2 2.7 3.6 1.7 1.1 1.1 1.0 2.4 5.0 4.1 4.3 3.5 2.2 3.5 1.5 2.3 1.4 2.2 2.2 1.4 1.8 1.5 2.3 2.5 5.0 1.012/16/2009 3.3 0.9 2.9 1.1 1.8 2.6 5.1 1.8 0.7 1.3 0.9 1.6 1.1 0.9 0.3 1.3 1.5 1.6 1.8 1.7 1.0 0.9 1.5 0.6 1.6 5.1 0.312/17/2009 1.2 0.9 1.1 0.8 0.5 0.9 0.7 0.8 0.8 1.1 1.5 1.6 1.2 0.9 0.5 0.5 0.9 1.7 1.9 2.0 1.0 2.5 1.5 1.4 1.2 2.5 0.512/18/2009 0.5 0.8 1.0 0.5 1.0 0.6 0.7 0.4 1.0 1.0 2.3 2.5 3.2 2.3 0.8 0.5 1.6 1.4 2.5 1.9 1.4 0.8 1.1 0.5 1.3 3.2 0.412/19/2009 0.6 1.4 2.1 0.8 0.5 0.6 0.7 0.9 0.7 0.5 0.6 0.8 0.9 0.8 0.6 0.4 0.7 1.4 1.8 1.2 0.9 1.0 0.6 0.5 0.9 2.1 0.412/20/2009 0.9 0.6 0.9 0.7 0.2 0.4 0.5 0.6 0.6 0.4 0.5 0.5 0.8 0.8 0.4 0.8 1.5 1.1 3.1 2.1 1.6 0.7 1.6 0.8 0.9 3.1 0.212/21/2009 0.7 0.9 0.7 0.8 0.6 0.9 0.7 0.4 1.1 1.0 1.4 1.0 0.8 1.2 0.9 0.7 1.0 0.8 1.5 0.9 1.5 0.6 1.1 1.0 0.9 1.5 0.412/22/2009 1.1 2.7 4.6 4.5 4.4 3.1 2.0 4.8 6.1 5.5 5.5 5.7 4.7 4.6 3.8 3.1 3.2 1.1 0.3 1.1 0.9 1.5 1.7 1.4 3.2 6.1 0.312/23/2009 2.3 4.1 3.0 4.2 4.1 4.2 1.2 1.1 1.2 1.0 1.0 2.3 2.8 1.8 1.1 1.4 1.9 1.4 1.8 1.8 1.2 1.0 0.6 1.0 2.0 4.2 0.612/24/2009 0.5 0.5 0.5 0.4 0.2 0.1 0.4 0.3 0.2 0.6 0.8 0.9 1.2 1.0 0.7 0.7 0.7 0.9 0.5 1.2 2.8 0.9 0.8 1.0 0.7 2.8 0.1Avg 1.8 1.8 1.7 1.7 1.8 1.4 1.3 1.2 1.5 1.9 1.8 2.0 2.2 2.2 1.9 1.7 1.8 2.0 2.2 2.1 2.0 1.7 1.5 1.5 1.8‐‐ ‐‐Max 5.4 4.8 4.6 4.9 7.1 4.6 5.1 4.8 6.1 8.8 6.9 6.3 6.2 7.2 6.3 4.7 3.6 4.0 4.3 5.1 6.3 5.9 4.8 5.4‐‐8.8‐‐Min 0.0 0.5 0.4 0.1 0.2 0.1 0.2 0.3 0.2 0.4 0.2 0.3 0.5 0.5 0.3 0.2 0.5 0.4 0.3 0.5 0.5 0.5 0.0 0.0‐‐ ‐‐0.0SAROADforBarrick,Cortez‐PipelineChannel:WS_msMonth:11/30/09‐12/24/09HourofdayDay 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Avg Max Min11/30/2009 296 168 257 264 326 174 162 10 83 86 112 92 47 132 75 72 334 280 270 269 277 286 314 270 194 334 1012/1/2009 270 323 64 163 60 341 339 69 147 177 56 114 53 47 65 64 4 310 275 257 299 263 312 243 180 341 412/2/2009 171 222 226 306 289 282 119 207 114 75 84 65 55 51 63 59 343 277 271 257 342 277 249 262 194 343 5112/3/2009 313 167 224 264 290 274 193 133 109 92 90 119 89 67 83 72 341 278 271 270 271 258 292 149 196 341 6712/4/2009 61 50 265 293 21 342 346 22 30 54 70 52 41 69 252 194 205 200 205 238 231 226 227 243 164 346 2112/5/2009 230 219 254 275 65 42 22 36 57 32 27 14 4 345 349 23 4 13 333 135 258 278 272 269 148 349 412/6/2009 268 226 252 330 314 310 329 135 0 70 51 23 278 325 72 330 347 23 262 151 225 218 227 223 208 347 012/7/2009 233 226 284 9 46 27 58 63 56 45 50 47 34 31 36 29 23 67 93 77 86 87 0 302 84 302 012/8/2009 272 269 297 314 323 295 260 261 47 10 152 121 66 17 29 10 251 262 248 126 227 290 265 345 198 345 1012/9/2009 309 282 219 0 124 318 343 308 35 43 117 45 50 66 69 9 272 249 157 294 170 247 20 274 167 343 012/10/2009 92 333 42 209 215 169 60 98 332 91 133 133 100 93 115 289 218 163 229 333 285 290 232 359 192 359 4212/11/2009 27 326 285 56 336 17 152 38 91 80 70 40 46 34 134 111 191 155 126 84 65 10 172 267 121 336 1012/12/2009 346 168 351 213 216 230 210 185 188 203 155 201 351 251 81 150 184 247 249 291 326 311 0 0 213 351 012/13/2009 0 283 201 227 240 167 183 186 204 234 221 217 225 228 233 230 237 218 199 231 246 245 241 230 214 283 012/14/2009 242 240 233 255 249 268 209 284 268 98 214 201 227 215 357 302 274 274 255 283 2 355 280 213 242 357 212/15/2009 228 227 292 239 240 341 345 12 268 243 235 258 234 274 221 231 216 224 217 213 246 184 186 226 233 345 1212/16/2009 241 280 231 326 358 278 227 255 299 201 212 17 61 5 328 182 252 238 317 258 316 275 222 276 236 358 512/17/2009 14 280 152 49 151 341 25 297 183 59 11 50 36 43 39 316 233 234 254 259 171 258 33 321 159 341 1112/18/2009 294 137 312 340 291 234 354 307 197 85 202 42 38 33 87 338 290 269 263 263 248 259 210 192 220 354 3312/19/2009 341 55 220 12 4 273 272 68 64 28 103 69 5 97 83 174 218 281 259 314 331 177 150 57 152 341 412/20/2009 287 149 354 32 31 73 114 8 148 104 88 71 78 33 77 167 29 302 231 190 345 289 198 325 155 354 812/21/2009 223 348 1 342 336 313 347 191 98 48 66 22 17 29 42 276 322 21 246 303 181 224 140 358 187 358 112/22/2009 229 172 257 229 241 273 167 21 41 51 48 41 46 52 37 23 6 314 257 210 221 166 230 232 148 314 612/23/2009 216 258 256 232 247 246 327 278 29 46 55 28 29 31 357 29 333 268 264 263 271 265 208 39 191 357 2812/24/2009 218 356 331 337 292 120 159 52 26 14 35 28 43 28 11 351 303 264 178 217 237 149 176 341 178 356 11Avg 217 231 234 213 212 230 213 141 125 91 106 84 90 104 132 161 217 217 237 231 235 235 194 241 183‐‐ ‐‐Max 346 356 354 342 358 342 354 308 332 243 235 258 351 345 357 351 347 314 333 333 345 355 314 359‐‐359‐‐Min 0 50 1 0 4 17 22 8 0 10 11 14 4 5 11 9 4 13 93 77 2 10 0 0‐‐ ‐‐0SAROADforBarrick,Cortez‐PipelineChannel:WD_degMonth:11/30/09‐12/24/09HourofdayDay 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Avg Max Min11/30/2009‐6.1‐5.6‐4.0‐4.4‐6.0‐7.4‐7.5‐5.9‐1.4 0.1 2.7 5.7 9.1 8.6 8.0 7.2 4.1 3.4 2.5 2.0 1.5‐1.0‐1.9‐3.1 0.0 9.1‐7.512/1/2009‐3.6‐4.3‐5.3‐6.3‐5.7‐7.4‐7.7‐6.8‐2.2 2.2 4.1 5.1 6.6 7.4 7.7 7.4 4.2 3.1 2.1 1.5 0.2‐2.2‐3.5‐3.4‐0.3 7.7‐7.712/2/2009‐4.3‐4.9‐4.4‐4.3‐8.4‐6.9‐8.6‐6.2‐2.9‐0.1 1.3 2.3 3.3 3.9 4.1 3.6 0.4‐0.3‐1.0‐2.8‐4.1‐3.3‐4.0‐4.5‐2.2 4.1‐8.612/3/2009‐5.9‐7.8‐7.4‐6.7‐8.8‐10.7‐11.6‐8.5‐4.5‐3.3‐1.3 0.2 0.9 1.2 1.7 1.0‐2.0‐2.8‐3.4‐4.0‐3.5‐4.1‐6.7‐8.2‐4.4 1.7‐11.612/4/2009‐8.7‐9.9‐9.5‐10.0‐10.4‐10.3‐11.8‐9.5‐7.6‐5.3‐1.3 0.9 2.6 2.7 4.3 6.3 5.9 5.0 4.2 6.1 6.1 6.3 6.0 6.7‐1.3 6.7‐11.812/5/2009 6.5 5.9 2.9 0.4‐4.2‐5.5‐6.1‐4.9‐4.3‐2.8‐2.5‐2.0‐2.2‐2.6‐3.4‐4.7‐5.8‐6.5‐8.7‐9.5‐10.0‐9.8‐9.9‐10.4‐4.2 6.5‐10.412/6/2009‐10.0‐10.6‐11.2‐15.3‐14.7‐14.7‐14.9‐14.5‐11.0‐9.7‐7.4‐5.9‐5.2‐4.0‐3.9‐4.6‐5.1‐5.2‐4.7‐6.3‐5.0‐5.7‐6.3‐6.7‐8.4‐3.9‐15.312/7/2009‐6.4‐6.8‐6.5‐7.6‐8.2‐8.2‐8.1‐7.9‐7.0‐6.4‐6.1‐5.9‐5.7‐5.5‐5.6‐5.9‐6.1‐6.8‐7.7‐8.3‐9.1‐9.5‐10.5‐11.2‐7.4‐5.5‐11.212/8/2009‐12.5‐12.3‐13.9‐14.4‐13.9‐16.8‐17.4‐15.7‐13.6‐11.6‐10.2‐8.3‐9.7‐9.9‐10.6‐11.5‐14.8‐14.1‐15.4‐18.0‐18.7‐19.7‐18.6‐19.8‐14.2‐8.3‐19.812/9/2009‐21.1‐23.0‐21.8‐22.5‐24.1‐22.6‐27.0‐22.5‐19.2‐18.1‐15.4‐14.0‐12.1‐10.8‐10.6‐12.7‐15.0‐14.3‐15.1‐16.2‐17.1‐14.3‐20.4‐19.7‐17.9‐10.6‐27.012/10/2009‐19.6‐20.5‐20.0‐21.9‐21.8‐22.7‐23.8‐22.8‐18.6‐15.8‐14.8‐12.2‐11.1‐10.3‐10.8‐10.8‐14.3‐13.9‐15.1‐16.0‐17.1‐18.2‐15.9‐16.3‐16.8‐10.3‐23.812/11/2009‐18.8‐18.2‐17.0‐16.0‐16.2‐16.4‐15.3‐15.5‐14.2‐11.2‐8.6‐6.1‐5.7‐4.5‐4.9‐6.7‐7.0‐6.4‐6.3‐6.4‐6.4‐7.0‐7.8‐8.1‐10.4‐4.5‐18.812/12/2009‐7.4‐7.2‐6.0‐1.6‐0.7‐1.3‐1.3‐1.4 0.2 1.0 3.4 4.7 3.9 3.4 3.4 3.3 3.2 2.1 2.3 1.6 1.3 1.0 0.5 0.1 0.4 4.7‐7.412/13/2009 0.4 1.5 1.6 1.5 2.4 0.6 1.4 1.8 2.0 2.3 2.6 3.1 3.2 3.6 3.5 3.2 2.1 0.8 1.9 1.5 1.6 1.1 0.5 0.8 1.9 3.6 0.412/14/2009‐0.1 0.4 0.1‐0.1 0.3‐0.8‐1.7‐2.6‐0.9‐0.7 0.4 2.3 3.3 3.7 2.1 2.1‐1.7‐1.8‐1.9‐2.3‐4.5‐4.8‐6.7‐5.2‐0.9 3.7‐6.712/15/2009‐1.5‐4.7‐3.2 0.0 0.1‐3.4‐3.6‐3.2 0.3 3.5 4.2 4.3 4.8 5.6 5.2 4.3 3.8 3.4 3.8 3.7 4.1 3.1 2.8 3.7 1.7 5.6‐4.712/16/2009 3.8 2.6 3.5 2.4 2.3 3.4 4.1 3.0 4.0 5.8 5.6 4.8 5.3 5.1 6.9 6.0 2.7 2.8 1.1 0.3‐1.4‐1.4‐2.5‐2.9 2.8 6.9‐2.912/17/2009‐3.5‐4.5‐3.9‐5.4‐5.4‐5.2‐5.3‐5.1‐2.6‐1.1‐0.2 0.9 1.5 2.9 3.6 2.0 0.2‐0.5‐0.4 0.3‐1.4 0.0‐1.5‐2.3‐1.5 3.6‐5.412/18/2009‐2.1‐2.7‐3.7‐3.1‐2.4‐3.6‐2.7‐2.6 0.9 1.7 3.9 3.4 2.8 3.3 4.3 3.3 0.7‐0.3‐0.6‐0.6‐1.2‐3.1‐4.0‐4.7‐0.5 4.3‐4.712/19/2009‐5.2‐6.4‐5.7‐6.8‐7.9‐7.9‐8.8‐8.5‐7.5‐6.7‐4.6‐4.0‐1.8 0.2‐0.1‐1.0‐2.9‐3.5‐2.1‐3.7‐5.1‐7.3‐6.5‐7.3‐5.0 0.2‐8.812/20/2009‐7.7‐8.8‐10.0‐9.7‐10.2‐10.4‐10.7‐10.5‐8.5‐7.2‐5.7‐4.8‐3.8‐3.8‐2.9‐2.9‐3.3‐4.0‐3.8‐1.9‐5.4‐4.8‐3.8‐6.3‐6.3‐1.9‐10.712/21/2009‐6.4‐6.7‐6.5‐6.3‐6.8‐7.0‐7.4‐6.8‐5.5‐4.5‐1.8‐2.1‐0.5 0.0 0.1‐0.8‐1.4‐1.3 0.3 0.7‐2.2‐2.6‐1.8‐2.1‐3.3 0.7‐7.412/22/2009‐1.8‐1.8‐0.9 1.2 1.4 0.6‐1.1‐1.4‐2.6‐3.5‐3.7‐3.5‐3.3‐3.7‐4.3‐5.0‐7.2‐8.5‐9.6‐8.8‐7.5‐6.6‐6.3‐5.9‐3.9 1.4‐9.612/23/2009‐7.0‐7.9‐8.1‐8.8‐9.4‐8.3‐11.6‐13.3‐9.8‐9.9‐8.1‐7.0‐6.3‐5.6‐4.5‐6.1‐8.4‐8.9‐9.0‐9.0‐10.5‐10.1‐10.7‐14.3‐8.9‐4.5‐14.312/24/2009‐14.5‐14.6‐14.2‐15.7‐16.6‐16.8‐17.2‐14.9‐11.9‐12.6‐11.5‐10.0‐9.1‐7.4‐6.4‐7.4‐10.1‐11.3‐11.3‐10.9‐9.2‐14.6‐13.9‐14.0‐12.3‐6.4‐17.2Avg‐6.5‐7.1‐7.0‐7.3‐7.8‐8.4‐9.0‐8.2‐5.9‐4.6‐3.0‐1.9‐1.2‐0.7‐0.5‐1.2‐3.1‐3.6‐3.9‐4.3‐5.0‐5.5‐6.1‐6.6‐4.9‐‐ ‐‐Max 6.5 5.9 3.5 2.4 2.4 3.4 4.1 3.0 4.0 5.8 5.6 5.7 9.1 8.6 8.0 7.4 5.9 5.0 4.2 6.1 6.1 6.3 6.0 6.7‐‐9.1‐‐Min‐21.1‐23.0‐21.8‐22.5‐24.1‐22.7‐27.0‐22.8‐19.2‐18.1‐15.4‐14.0‐12.1‐10.8‐10.8‐12.7‐15.0‐14.3‐15.4‐18.0‐18.7‐19.7‐20.4‐19.8‐‐ ‐‐ ‐27.0SAROADforBarrick,Cortez‐PipelineChannel:Temp_CMonth:11/30/09‐12/24/09HourofdayDay 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Avg Max Min11/30/2009 64 66 63 63 71 73 74 68 53 50 43 37 30 31 32 34 42 45 47 48 50 58 60 65 53 74 3012/1/2009 64 69 71 74 74 77 79 75 59 42 38 36 33 33 32 33 40 45 49 50 54 59 64 64 55 79 3212/2/2009 69 72 71 71 78 77 81 77 63 56 56 55 54 52 51 52 59 63 63 68 74 70 72 70 66 81 5112/3/2009 73 78 78 75 78 84 84 81 68 64 55 45 37 34 32 31 39 45 45 47 44 46 52 57 57 84 3112/4/2009 60 62 61 60 62 64 62 55 48 41 32 25 21 21 18 13 10 12 14 13 14 16 19 22 34 64 1012/5/2009 21 21 26 32 48 53 55 52 49 41 37 31 30 29 34 46 44 44 48 52 56 58 58 59 43 59 2112/6/2009 58 56 60 68 70 71 71 70 59 54 47 41 46 43 39 55 74 78 70 85 73 73 72 72 63 85 3912/7/2009 71 77 77 83 86 86 87 87 86 85 85 85 85 85 86 87 88 86 87 87 87 86 85 85 85 88 7112/8/2009 79 74 76 77 80 82 82 81 75 69 61 55 64 69 73 75 79 79 80 81 82 81 81 81 76 82 5512/9/2009 80 79 78 79 77 79 75 77 76 76 79 79 79 77 71 73 78 77 79 79 81 78 78 81 78 81 7112/10/2009 81 80 80 79 79 79 78 78 77 77 78 78 71 68 71 71 78 81 80 83 83 82 83 82 78 83 6812/11/2009 81 82 82 82 82 82 82 82 81 76 67 58 58 55 58 80 86 87 87 88 87 88 88 88 79 88 5512/12/2009 88 89 88 86 88 89 85 82 78 76 67 59 64 70 69 68 70 84 83 88 90 91 92 92 81 92 5912/13/2009 92 89 85 77 72 75 76 75 75 75 73 71 72 68 67 65 69 73 71 74 75 76 78 76 75 92 6512/14/2009 78 78 79 79 79 82 83 85 83 85 82 77 75 72 77 75 86 84 84 85 86 86 89 85 82 89 7212/15/2009 74 76 75 62 62 79 81 78 65 50 50 50 49 47 51 57 60 65 62 62 59 68 68 63 63 81 4712/16/2009 64 72 66 75 76 69 62 71 68 59 60 66 63 65 55 57 74 72 77 80 84 85 85 88 71 88 5512/17/2009 88 89 89 90 90 89 90 90 89 82 79 75 73 68 65 71 79 81 82 79 84 82 83 87 82 90 6512/18/2009 87 88 89 90 89 89 89 89 78 71 66 70 72 71 66 69 79 82 83 82 83 86 87 90 81 90 6612/19/2009 90 90 90 89 89 89 88 88 88 88 89 88 87 75 77 80 86 88 84 87 88 90 90 90 87 90 7512/20/2009 90 89 88 88 87 87 87 87 87 88 88 89 89 90 90 90 90 90 88 79 88 88 83 89 88 90 7912/21/2009 89 89 89 90 89 89 90 90 88 85 80 79 75 75 75 77 80 80 74 73 80 83 83 84 83 90 7312/22/2009 89 91 92 87 85 86 89 78 74 82 85 80 79 79 79 76 78 77 81 77 75 75 74 74 81 92 7412/23/2009 74 76 75 76 77 74 81 82 71 70 68 71 70 67 64 69 76 80 80 80 84 83 82 86 76 86 6412/24/2009 85 85 85 84 83 83 83 83 82 81 82 79 75 70 66 69 78 83 83 83 78 84 86 85 81 86 66Avg 76 77 76 77 78 80 80 78 73 69 66 63 62 60 60 63 69 71 71 72 74 75 76 77 72‐‐ ‐‐Max 92 91 92 90 90 89 90 90 89 88 89 89 89 90 90 90 90 90 88 88 90 91 92 92‐‐92‐‐Min 21 21 26 32 48 53 55 52 48 41 32 25 21 21 18 13 10 12 14 13 14 16 19 22‐‐ ‐‐10SAROADforBarrick,Cortez‐PipelineChannel:RH_percentMonth:11/30/09‐12/24/09HourofdayDay 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Avg Max Min11/30/2009 643 643 643 643 643 643 643 643 643 643 642 641 641 640 639 639 639 639 639 639 639 639 639 639 641 643 63912/1/2009 639 638 639 638 638 638 638 638 638 638 638 637 637 636 636 636 636 636 636 636 637 637 637 637 637 639 63612/2/2009 637 637 637 637 637 638 638 638 638 638 638 638 637 637 637 637 637 637 637 637 638 638 638 638 637 638 63712/3/2009 639 639 639 639 640 640 641 641 642 642 642 642 641 641 641 641 641 642 642 642 642 642 642 642 641 642 63912/4/2009 642 642 642 642 641 641 641 641 641 640 640 639 638 637 637 636 635 635 635 635 634 634 633 633 638 642 63312/5/2009 632 632 632 632 633 634 634 634 634 634 634 634 633 633 633 633 633 633 633 633 633 633 632 632 633 634 63212/6/2009 632 632 631 631 631 630 630 630 630 630 629 628 627 627 626 626 626 626 627 627 627 627 627 627 629 632 62612/7/2009 628 627 627 627 627 627 627 627 627 626 626 625 624 624 624 624 624 624 624 625 625 626 626 627 626 628 62412/8/2009 627 628 628 629 630 631 632 632 633 634 634 633 633 633 633 634 634 634 635 635 635 636 636 637 633 637 62712/9/2009 637 637 637 637 637 637 637 637 638 638 637 637 636 636 636 637 637 637 637 637 637 637 637 637 637 638 63612/10/2009 637 637 637 637 637 637 637 637 638 638 638 637 637 636 636 636 636 636 636 636 636 636 636 636 637 638 63612/11/2009 636 636 636 636 635 635 635 635 635 635 635 634 634 634 634 634 634 634 634 634 634 634 634 634 634 636 63412/12/2009 633 633 633 633 633 632 632 632 633 633 633 632 631 631 630 630 630 629 628 628 627 627 627 626 631 633 62612/13/2009 626 627 627 627 627 628 628 629 630 630 631 631 632 632 632 633 633 634 634 634 635 635 635 636 631 636 62612/14/2009 636 636 637 637 637 637 638 638 639 640 640 639 639 639 639 639 639 639 640 640 640 640 640 640 639 640 63612/15/2009 640 640 640 640 640 640 640 640 640 641 641 641 640 640 640 640 640 640 641 641 641 641 641 640 640 641 64012/16/2009 641 641 641 641 641 641 641 641 642 642 642 642 642 642 642 642 642 642 642 642 642 642 643 643 642 643 64112/17/2009 643 643 643 643 643 643 643 643 644 644 643 643 643 642 643 643 643 643 643 643 643 643 643 643 643 644 64212/18/2009 643 642 642 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 64212/19/2009 643 643 643 643 643 643 643 643 643 643 643 642 642 642 641 641 641 641 641 641 641 641 641 641 642 643 64112/20/2009 641 641 640 640 640 640 640 640 640 640 639 639 638 638 638 638 638 638 638 637 638 638 637 637 639 641 63712/21/2009 637 638 637 637 637 637 637 636 636 636 636 635 634 633 633 632 632 631 631 631 630 630 630 630 634 638 63012/22/2009 630 630 629 629 629 628 629 629 630 631 631 631 631 632 632 633 634 635 635 636 636 637 637 638 632 638 62812/23/2009 638 639 640 640 640 641 641 641 642 643 642 642 642 642 642 642 642 643 643 643 643 643 644 644 642 644 63812/24/2009 644 644 644 644 644 644 644 644 644 644 644 644 644 643 643 643 643 643 643 643 642 643 642 642 644 644 642Avg 637 637 637 637 637 637 637 637 638 638 638 637 637 637 636 636 636 637 637 637 637 637 637 637 637‐‐ ‐‐Max 644 644 644 644 644 644 644 644 644 644 644 644 644 643 643 643 643 643 643 643 643 643 644 644‐‐644‐‐Min 626 627 627 627 627 627 627 627 627 626 626 625 624 624 624 624 624 624 624 625 625 626 626 626‐‐ ‐‐624SAROADforBarrick,Cortez‐PipelineChannel:BP_mmHgMonth:11/30/09‐12/24/09HourofdayDay 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Avg Max Min11/30/2009‐13.8‐14.8‐14.8‐13.4‐14.2‐16.2‐15.4‐12.5‐6.7‐2.2 1.1 3.8 5.1 6.2 6.8 5.9 1.3‐3.8‐7.6‐8.7‐9.7‐11.8‐12.6‐13.9‐6.7 6.8‐16.212/1/200912/2/200912/3/2009‐16.3‐18.3‐18.5‐18.6‐19.0‐20.2‐21.5‐18.3‐9.3‐4.7‐3.1‐1.4‐0.4 0.6 0.6‐0.4‐3.0‐10.2‐12.4‐14.5‐14.3‐15.1‐14.6‐17.1‐11.2 0.6‐21.512/4/200912/5/200912/6/2009‐19.8‐18.5‐20.4‐21.7‐23.3‐24.0‐23.8‐21.6‐15.4‐12.0‐8.8‐6.9‐6.0‐5.0‐5.0‐5.6‐6.6‐7.3‐7.6‐7.6‐8.2‐8.6‐9.2‐9.4‐12.6‐5.0‐24.012/7/200912/8/200912/9/2009‐33.2‐33.1‐33.9‐34.3‐34.4‐34.6‐34.8‐33.4‐26.8‐21.9‐17.8‐15.9‐14.0‐13.1‐12.0‐13.3‐17.6‐24.1‐26.4‐28.8‐29.6‐29.3‐30.4‐31.1‐26.0‐12.0‐34.812/10/200912/11/200912/12/2009‐14.1‐11.8‐11.1‐8.7‐3.1‐1.9‐1.7‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐0.3‐0.6‐0.8‐0.9‐1.4‐4.6 0.3‐14.112/13/200912/14/200912/15/2009‐13.8‐14.5‐13.3‐10.3‐9.3‐9.0‐7.3‐7.4‐4.6 0.1 1.5 2.3 2.9 4.2 3.8 3.9 2.9 2.2 1.7 1.7 1.3 0.2‐0.2‐0.4‐2.6 4.2‐14.512/16/200912/17/200912/18/2009‐‐ ‐‐ ‐9.0‐9.0‐8.4‐7.9‐6.9‐6.9‐3.8‐0.3 2.8 3.9 2.6 2.2 2.9 2.6‐0.6‐5.2‐7.4‐9.1‐9.7‐10.9‐11.9‐12.8‐4.7 3.9‐12.812/19/200912/20/200912/21/2009‐13.8‐14.3‐14.4‐13.7‐13.2‐13.1‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐13.7‐13.1‐14.412/22/200912/23/200912/24/2009‐24.0‐24.9‐24.8‐25.4‐26.2‐26.8‐26.4‐25.1‐17.6‐13.3‐13.1‐10.3‐8.6‐7.5‐7.0‐8.1‐11.5‐18.0‐20.4‐22.4‐22.1‐22.0‐23.3‐23.2‐18.8‐7.0‐26.8Avg‐18.6‐18.8‐17.8‐17.2‐16.8‐17.1‐17.2‐17.9‐12.0‐7.8‐5.3‐3.5‐2.6‐1.8‐1.4‐2.1‐5.0‐9.5‐11.4‐11.1‐11.6‐12.3‐12.9‐13.7‐11.2‐‐ ‐‐Max‐13.8‐11.8‐9.0‐8.7‐3.1‐1.9‐1.7‐6.9‐3.8 0.1 2.8 3.9 5.1 6.2 6.8 5.9 2.9 2.2 1.7 1.7 1.3 0.2‐0.2‐0.4‐‐6.8‐‐Min‐33.2‐33.1‐33.9‐34.3‐34.4‐34.6‐34.8‐33.4‐26.8‐21.9‐17.8‐15.9‐14.0‐13.1‐12.0‐13.3‐17.6‐24.1‐26.4‐28.8‐29.6‐29.3‐30.4‐31.1‐‐ ‐‐ ‐34.8‐‐IndicateinvaliddataSAROADforBarrick,Cortez‐HCNChannel:T_AMB_CMonth:11/30/09‐12/24/09HourofdayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayDay 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Avg Max Min11/30/2009 76 77 76 79 80 81 83 74 58 48 41 35 34 33 32 34 44 57 64 67 69 73 74 77 61 83 3212/1/200912/2/200912/3/2009 88 83 87 87 85 84 83 85 71 59 56 42 32 30 28 32 38 57 57 61 62 66 67 70 63 88 2812/4/200912/5/200912/6/2009 75 74 77 79 78 78 79 78 65 59 51 44 41 40 43 52 74 80 80 92 86 82 82 81 69 92 4012/7/200912/8/200912/9/2009 72 72 71 70 71 70 70 71 77 79 83 83 76 71 70 74 81 81 80 76 77 76 75 74 75 83 7012/10/200912/11/200912/12/2009 92 94 93 95 91 86 84‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐91 97 98 99 99 93 99 8412/13/200912/14/200912/15/2009 91 91 92 94 94 94 93 93 88 64 60 55 56 51 52 51 58 64 68 69 73 83 86 88 75 94 5112/16/200912/17/200912/18/2009‐‐ ‐‐95 96 95 95 95 94 85 74 63 60 67 68 65 67 78 91 95 96 95 95 94 93 84 96 6012/19/200912/20/200912/21/2009 92 91 93 92 92 92‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐92 93 9112/22/200912/23/200912/24/2009 82 82 82 81 80 80 83 81 82 72 70 65 63 62 62 67 74 85 86 84 84 84 83 83 77 86 62Avg 84 83 85 86 85 85 84 82 75 65 61 55 53 51 50 54 64 73 76 79 80 82 82 83 77‐‐ ‐‐Max 92 94 95 96 95 95 95 94 88 79 83 83 76 71 70 74 81 91 95 96 97 98 99 99‐‐99‐‐Min 72 72 71 70 71 70 70 71 58 48 41 35 32 30 28 32 38 57 57 61 62 66 67 70‐‐ ‐‐28‐‐IndicateinvaliddataSAROADforBarrick,Cortez‐HCNChannel:RH_percentMonth:11/30/09‐12/24/09HourofdayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayDay 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Avg Max Min11/30/2009 659 659 659 659 658 658 659 659 659 659 658 657 657 656 656 656 656 656 656 656 656 656 656 655 657 659 65512/1/200912/2/200912/3/2009 655 656 656 656 656 657 657 657 658 658 658 658 657 657 657 657 657 658 658 658 658 658 658 658 657 658 65512/4/200912/5/200912/6/2009 650 650 650 650 650 649 649 649 649 648 648 647 646 646 646 646 646 646 646 647 646 647 647 647 648 650 64612/7/200912/8/200912/9/2009 654 654 654 654 654 654 655 655 655 655 654 654 654 654 654 654 654 654 654 654 654 654 655 655 654 655 65412/10/200912/11/200912/12/2009 651 651 651 651 651 650 650‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐647 646 646 646 646 649 651 64612/13/200912/14/200912/15/2009 656 656 656 656 656 656 656 656 657 657 657 657 656 656 656 656 656 657 657 657 657 657 657 657 656 657 65612/16/200912/17/200912/18/2009‐‐ ‐‐658 658 658 659 659 659 659 659 659 658 658 658 658 658 658 658 658 658 659 659 659 659 658 659 65812/19/200912/20/200912/21/2009 654 655 654 654 654 654‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐654 655 65412/22/200912/23/200912/24/2009 659 659 660 659 659 660 660 660 660 660 660 659 659 659 659 659 659 659 659 659 658 658 658 658 659 660 658Avg 655 655 655 655 655 655 656 656 656 656 656 656 655 655 655 655 655 655 655 654 654 654 654 654 655‐‐ ‐‐Max 659 659 660 659 659 660 660 660 660 660 660 659 659 659 659 659 659 659 659 659 659 659 659 659‐‐660‐‐Min 650 650 650 650 650 649 649 649 649 648 648 647 646 646 646 646 646 646 646 647 646 646 646 646‐‐ ‐‐646‐‐IndicateinvaliddataNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DaySAROADforBarrick,Cortez‐HCNChannel:BP_mmHgMonth:11/30/09‐12/24/09HourofdayNon‐Run‐DayNon‐Run‐Day

# APPENDIX B 

# HCN Data

### Page 1 of 2 Thu, 12/31/09 3:29 PM 

# ANALYTICAL REPORT

Tom Brauch Air Sciences, Inc. 1301 Washington Ave, Suite 200 Golden, CO 80401 Phone:

E-mail: (303) 988-2960 x 207

tbrauch@airsci.com Report Date December 31, 2009

Project Manager Rand Potter Workorder: 9353014 Purchase Order: Client Project ID: Air Sciences 121809

5956-5

Analytical Results
12/9/2009 12/18/2009 9353014001 Sample ID:
Lab ID: Media: Collected:
Received: SKC 226-28, Soda Lime-200/600 59561209-1 Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm 

## NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

0.21 NA 0.76 NA Hydrogen Cyanide



## 12/12/2009 12/18/2009 9353014002 Sample ID:
Lab ID: Media: Collected:
Received: SKC 226-28, Soda Lime-200/600 59561212-2 Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm 

## NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

0.21 NA 0.79 NA Hydrogen Cyanide



## 12/15/2009 12/18/2009 9353014003 Sample ID:
Lab ID: Media: Collected:
Received: SKC 226-28, Soda Lime-200/600 59561215-3 Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm 

## NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

0.21 NA 0.91 NA Hydrogen Cyanide



## 12/18/2009
9353014004 Sample ID:
Lab ID: Media: Received: SKC 226-28, Soda Lime-200/600 59561217-Blank Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm 

## NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

0.21 NA <0.21 NA Hydrogen Cyanide

IHREP-V9.7

### Page 2 of 2 Thu, 12/31/09 3:29 PM 

# ANALYTICAL REPORT

Project Manager Rand Potter Workorder: 9353014 Purchase Order: Client Project ID: Air Sciences 121809

5956-5

Report Authorization

Method: NIOSH 6010

Sarah E. Adamson Rosemary Hanks Analyst Peer Review

Phone: (801) 266-7700 Email: lab@datachem.com Web: www.datachem.com 

## Laboratory Contact Information ALS Laboratory Group (formerly DataChem Laboratorie s, Inc.) 960 W Levoy Drive Salt Lake City, Utah 84123

The results provided in this report relate only to the items tested. Samples were received in acceptable condition unles s otherwise noted. Samples have not been blank corrected unless otherw ise noted. This test report shall not be reproduced, except in full, without written approval of ALS Laboratory G roup.
ALS Laboratory Group is accredited by AIHA for spec ific fields of testing as documented in its current scope of accreditation (ID#101574) which is available on request by contac ting your project manager or view on the internet a t http://www.aiha.org. The quality systems implemented in the laboratory apply to all methods performed by ALS Laboratory Group r egardless of this current scope of accreditation which does not include perfo rmance based methods, modified methods, and methods applied to matrices not listed in the methods.
ALS DataChem provides professional analytical servi ces for all samples submitted. ALS Laboratory Grou p is not in a position to interpret the data and assumes no responsibility fo r the quality of the samples submitted.

All quality control samples processed with the samp les in this report yielded acceptable results unles s otherwise noted. 

## General Lab Comments

LOD = Limit of Detection = MDL = Method Detection L imit, A statistical estimate of method/media/instru ment sensitivity. LOQ = Limit of Quantitation = RL = Reporting Limit, A verified value of method/media/instrument sensit ivity. ND = Not Detected, Testing result not detected abov e the LOD or LOQ. ** No result could be reported, see sample comments for details. < This testing result is less than the numerical va lue. ( ) This testing result is between the LOD and LOQ and has higher analytical uncertainty than values a t or above the LOQ. 

## Definitions

IHREP-V9.7

### Page 1 of 2 Thu, 12/31/09 3:33 PM 

# ANALYTICAL REPORT

Tom Brauch Air Sciences, Inc. 1301 Washington Ave, Suite 200 Golden, CO 80401 Phone:

E-mail: (303) 988-2960 x 207

tbrauch@airsci.com Report Date December 31, 2009

Project Manager Rand Potter Workorder: 9362011 Purchase Order: Client Project ID: Air Sciences Inc 122809

5956-5

Analytical Results
12/18/2009 12/28/2009 9362011001 Sample ID:
Lab ID: Media: Collected:
Received: SKC 226-28, Soda Lime-200/600 595612182009-1 Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm 

## NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

0.21 NA 1.9 NA Hydrogen Cyanide



## 12/18/2009 12/28/2009 9362011002 Sample ID:
Lab ID: Media: Collected:
Received: SKC 226-28, Soda Lime-200/600 595612212009-2 Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm 

## NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

0.21 NA 2.5 NA Hydrogen Cyanide



## 12/18/2009 12/28/2009 9362011003 Sample ID:
Lab ID: Media: Collected:
Received: SKC 226-28, Soda Lime-200/600 595612242009-3 Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm 

## NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

0.21 NA <0.21 NA Hydrogen Cyanide



## 12/18/2009 12/28/2009 9362011004 Sample ID:
Lab ID: Media: Collected:
Received: SKC 226-28, Soda Lime-200/600 Blank Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm 

## NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

0.21 NA <0.21 NA Hydrogen Cyanide

IHREP-V9.7

### Page 2 of 2 Thu, 12/31/09 3:33 PM 

# ANALYTICAL REPORT

Project Manager Rand Potter Workorder: 9362011 Purchase Order: Client Project ID: Air Sciences Inc 122809

5956-5

Report Authorization

Method: NIOSH 6010

Sarah E. Adamson Rosemary Hanks Analyst Peer Review

Phone: (801) 266-7700 Email: lab@datachem.com Web: www.datachem.com 

## Laboratory Contact Information ALS Laboratory Group (formerly DataChem Laboratorie s, Inc.) 960 W Levoy Drive Salt Lake City, Utah 84123

The results provided in this report relate only to the items tested. Samples were received in acceptable condition unles s otherwise noted. Samples have not been blank corrected unless otherw ise noted. This test report shall not be reproduced, except in full, without written approval of ALS Laboratory G roup.
ALS Laboratory Group is accredited by AIHA for spec ific fields of testing as documented in its current scope of accreditation (ID#101574) which is available on request by contac ting your project manager or view on the internet a t http://www.aiha.org. The quality systems implemented in the laboratory apply to all methods performed by ALS Laboratory Group r egardless of this current scope of accreditation which does not include perfo rmance based methods, modified methods, and methods applied to matrices not listed in the methods.
ALS DataChem provides professional analytical servi ces for all samples submitted. ALS Laboratory Grou p is not in a position to interpret the data and assumes no responsibility fo r the quality of the samples submitted.

All quality control samples processed with the samp les in this report yielded acceptable results unles s otherwise noted. 

## General Lab Comments

LOD = Limit of Detection = MDL = Method Detection L imit, A statistical estimate of method/media/instru ment sensitivity. LOQ = Limit of Quantitation = RL = Reporting Limit, A verified value of method/media/instrument sensit ivity. ND = Not Detected, Testing result not detected abov e the LOD or LOQ. ** No result could be reported, see sample comments for details. < This testing result is less than the numerical va lue. ( ) This testing result is between the LOD and LOQ and has higher analytical uncertainty than values a t or above the LOQ. 

## Definitions

IHREP-V9.7

# APPENDIX C 

# Site Check Forms, Audits, and Calibration

# APPENDIX D 

# Hydrogen Cyanide (HCN) Fence Line Monitoring Plans

# Site-Specific Hydrogen Cyanide (HCN) Fence Line Monitoring Plan

B

ARRICK 

# C ORTEZ


# , I NC



# .

P ROJECT 

## 59-52-10 O

CTOBER 

## 2009Cortez Site-Specific Hcn Monitoring Plan_V2.Docx 

### ii 

# CONTENTS Page

1 INTRODUCTION ................................................................................................................ ............................................ 1 1.1 Mine Description and Proposed Monitoring .................................................................................. .......................... 1

2 METEOROLOGY ................................................................................................................. .......................................... 2 2.1 Prevailing Wind Direction ................................................................................................. ....................................... 2

3 PROPOSED HCN MONITORING SITE ................................................................................................ ......................... 4 3.1 Operations Boundary and Nearest Population Areas .......................................................................... ................... 4 3.2 Potential Sources of HCN .................................................................................................. ..................................... 4

3.2.1 Tailings Impoundment .................................................................................................... ................................. 4 3.2.2 Mill Area ............................................................................................................... ........................................... 4 3.2.3 Leach Pads .............................................................................................................. ....................................... 4 3.3 Proposed HCN Monitor Location ............................................................................................. ............................... 5

4 PROPOSED MODIFICATIONS TO THE GENERAL HCN MONITORING PLAN ......................................................... 6



## Figures
Figure 2.1: Calendar Year 2008 Wind Rose ..................................................................................... ............................... 2 Figure 2.2: Calendar Quarter Wind Roses for 2008 ............................................................................. ............................ 3



## Appendices
Appendix A: Cortez Site Figures Figure 1: Proposed HCN Monitoring Site (small scale) Figure 2: Proposed HCN Monitoring Site (large scale) Figure 3: Potential HCN Sources Figure 4: Potential HCN Sources, Mill Area Appendix B: Hydrogen Cyanide (HCN) Fence Line Monitoring PlanCortez Site-Specific Hcn Monitoring Plan_V2.Docx 

### 1 

## SECTION 1 

# INTRODUCTION

1.1 Mine Description and Proposed Monitoring

Barrick Cortez, Inc. (Cortez) operates a gold mining facility located approximately 38 miles south of Interstate 80, Exit #261 (Beowawe exit) on Stat e Route 306. The facility operates both open-pit and underground mines. Gold recovery operations include: crushing, milling, heap and tank leaching, carbon adsorption, stripping and regene ration, electrowinning, and smelting. The leach solutions used in the gold recovery processes contain cyanide. These solutions have the potential for low levels of hydrogen cyanide (HCN) formation and emission to the atmosphere. To assess the ambient concentrations of HCN emissions, Cortez plans to install and operate an HCN monitor downwind of the potential HCN sources at the boundary of the Cortez operations area.

The HCN monitoring equipment and sa mpling procedures will follow the Hydrogen Cyanide (HCN) Fence Line Monitoring Plan , approved by EPA on October 9, 2009 (General HCN Monitoring Plan). This plan is provided in Appe ndix B. The purposes of the site-specific plan described herein are to identify the location where the monitor will be sited and to identify any modifications to the monitoring equipment and sampling procedures described in the General HCN Monitoring Plan that are specific to Cortez. Per EPA’s instructions, the site location takes into consideration the proximity of the HCN so urces to public access areas and the prevailing wind direction (i.e., the monitor should be placed in the predominate downwind direction from the HCN emission sources). The site location al so takes into consideration accessibility for the Cortez maintenance and project technicians.

The following sections describe the predominant wind direction, the Cortez boundary of public access, the nearest population areas to this bo undary, the potential sources of HCN emissions and their locations, and the proposed HCN monitoring site.Cortez Site-Specific Hcn Monitoring Plan_V2.Docx 

### 2 

## SECTION 2 

# METEOROLOGY

2.1 Prevailing Wind Direction

Cortez currently operates a meteorological station. This station is located at 526,690 meters east, 4,456,403 meters north, UTM Zone 11N, NAD83, approximately 1.7 miles east of the mill. Figure 2.1 summarizes the hourly wind directions (the direction from which the wind is blowing) and wind speeds for the 2008 calendar year. Figure 2.2 provides wind roses for each calendar quarter of 2008. As shown by the annual and quarterly wind roses, the prevailing winds are from the west to southwest, with the most predominant annual wind direction from the west-southwest and the second most predominant annual wind direction from the west.

Figure 2.1: Calendar Year 2008 Wind Rose

2%

4%

6%

8%

10%

12%

14%

16%

18%

20% N

NNE

NE

ENE

E

ESE

SE

SSE
S SSW SW WSW W WNW NW NNW

2 4 8 12 18 m p h

Wind Frequency ‐ Hourly Met .Data 01/01/08 ‐ 12/31/08 Calm hours = 89 Missing hours = 121 Number of non

‐ calm/missing hours = 8,574Cortez Site-Specific Hcn Monitoring Plan_V2.Docx 

### 3 Figure 2.2: Calendar Quarter Wind Roses for 2008



## First Quarter Second Quarter 01/01/08 - 03/31/08 04/01/08 - 05/30/08

Third Quarter Fourth Quarter 06/01/08 - 09/30/08 10/01/08 - 12/31/08 3%

6%

9%

12%

15%

18%

21%

24%

27%

30% N

NNE

NE

ENE

E

ESE

SE

SSE
S SSW SW WSW W WNW NW NNW

2 4 8 12 18 m p h

Wind Frequency ‐ Hourly Met. Data Calm hours = 44 Missing hours = 0 Number of non

‐ calm/missing hours = 2,140 2%

4%

6%

8%

10%

12%

14%

16%

18%

20% N

NNE

NE

ENE

E

ESE

SE

SSE
S SSW SW WSW W WNW NW NNW

2 4 8 12 18 m p h

Wind Frequency ‐ Hourly Met. Data Calm hours = 1 Missing hours = 0 Number of non

‐ calm/missing hours = 2,183

2%

4%

6%

8%

10%

12%

14%

16%

18%

20% N

NNE

NE

ENE

E

ESE

SE

SSE
S SSW SW WSW W WNW NW NNW

2 4 8 12 18 m p h

Wind Frequency ‐ Hourly Met. Data Calm hours = 0 Missing hours = 0 Number of non

‐ calm/missing hours = 2,208 2%

4%

6%

8%

10%

12%

14%

16%

18%

20% N

NNE

NE

ENE

E

ESE

SE

SSE
S SSW SW WSW W WNW NW NNW

2 4 8 12 18 m p h

Wind Frequency ‐ Hourly Met. Data
Calm hours = 44 Missing hours = 121 Number of non

‐ calm/missing hours = 2,043Cortez Site-Specific Hcn Monitoring Plan_V2.Docx 

### 4 

## SECTION 3 

# PROPOSED HCN MONITORING SITE

3.1 Operations Boundary a nd Nearest Population Areas

Aerial photos and shaded relief maps are proved in Appendix A as Figures 1 through 4. Figure 1 provides an aerial photo of the mine site, the northeastern operations boundary, and the nearest residences to the Cortez operations boundary. The nearest residences ar e ranch houses owned by Barrick and are located approximately 1.3 miles from the northeast corner of the operations boundary.

Figure 2 provides a shaded relief map of the entire Cortez claims boundary and neighboring towns. The nearest town is Crescent Valley located approximately 10 miles north-northeast of the Cortez operations boundary and just north of the Cortez claims boundary. Cortez restricts public access primarily within the smaller operations boundary. The other nearby towns are Battle Mountain, Beowawe, and Carlin. These towns are all located more than 30 miles north the Cortez operations boundary.



# 3.2 Potential Sources of HCN

Figures 3 and 4 highlight the potential sources of HCN emissions at Cortez. These sources include a tailings impoundment, two leach pads (Area 28 and Area 30), and stacks and tanks at the mill area. A closer view of the mill area HCN sources is shown in Figure 4.


# 3.2.1 Tailings Impoundment
Spent cyanide solution used in the mill to extrac t gold in the Carbon-in-Leach (CIL) tanks is first sent to a cyanide kill system and then discharged to the tailings impoundment. The residual cyanide in the tails solution has the potential to produce HCN air emissions from both the standing water within the impoundment and the wetted tailings material around the water. The tailings impoundment is shown in Figure 3.



# 3.2.2 Mill Area
The mill area, shown in Figure 4, contains stack and tank sources of HCN emissions. Stack sources include the east and west electrowinning cells, the pregnant and barren tanks, and the carbon-in-column (CIC) tank. Th e tank sources are the eight CIL tanks, which are open to the atmosphere at the top. As discussed above, these processes use aqueous cyanide solutions, which have the potential for HCN emissions.



# 3.2.3 Leach Pads
Cortez operates the Area 28 and 30 leach pads. Cyanide leach solution is applied to portions of these pads via drip emitters. Potential HCN emissions come from the cyanide solution applied toCortez Site-Specific Hcn Monitoring Plan_V2.Docx 

### 5 

## the ore on the pads, the pregnant ponds used to collect solution from the pads, and the barren ponds used to supply solution to the pads. These pads and ponds are shown in Figure 3.


# 3.3 Proposed HCN Monitor Location

As discussed in Section 2.1, the prevailing winds at Cortez are from the west to southwest with the most predominant annual wind direction fr om the west-southwest and the second most predominant annual wind direction from the west. Thus, Cortez proposes to place the monitor east of the tailings impoundment, Area 28, and the mill, and east -northeast of Area 30. This location is the closest downwind point of pub lic access to the potential HCN sources.

The proposed monitor location can be reached via a road maintained by Cortez. See Figure 1. The proposed site coordinates are 532,667 meters east, 4,457,396 meters north, UTM Zone 11N,

NAD83.Cortez Site-Specific Hcn Monitoring Plan_V2.Docx 

### 6 

## SECTION 4 

# PROPOSED MODIFICATIONS TO THE GENERAL HCN MONITORING PLAN

Cortez does not propose any modifications to the General HCN Monitoring Plan with regards to the HCN sampling equipment. Cortez does, howeve r, propose to use its existing meteorological station to collect the meteorological parameters outlined in the General HCN Monitoring Plan in lieu of installing the meteorological measurement equipment described in the general plan. The existing meteorological station is located between the HCN sources and the proposed HCN monitoring site and, therefore, it will provid e representative data for the overall mine and monitoring site. See Figure 2.

Cortez is currently reviewing the availability of line power for the HCN monitoring station. If line power is not readily available, then the station will be powered by the solar power system described in the General HCN Monitoring Plan.

# APPENDIX A 

# Cortez Site Figures

# [AREA 28

AREA 30 Tailings Storage Impoundment Barrick Owned Ranch Houses

Proposed Site

1 5 4

7 3 6 2 8 7

8 5

8 9 9 8 5 6 1 2 3 5

12 4

11

11 30

31 19 17

20

32 25 20

29 27

32 18

28 26 24

33 34 15 10

22 21 16

35 29 17 13 12

36 23 14

10 7 6

18

19

6 30

31

7 9 4

13 14 15 16 17 18 9

17 33

4

18 16 

### T28N:R47E T28N:R48E

T27N:R47E T27N:R48E 525000

525000 530000

530000 535000

5350004455000445500044600004460000

Datum: NAD83 UTM Zone 11N Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Com pliance\MXD\PotentialHCN102009_Fig1.mxd 

# · Barrick Cortez Mines Lander & Eureka Counties, Nevada 

# Proposed HCN Monitoring Site

Figure 1

October 08, 2009

0 5,000 10,000 15,000 20,000 Feet 

### 0 1,000 2,000 3,000 4,000 5,000 6,000 Meters 

## Cortez Operations Area
Dean Ranch (private land) Potential HCN Source Areas



# [Proposed HCN Monitoring Site Looking North-Northeast

Looking East-Southeast

SITE_ID EAST NORTH AQM-001 532667 4457396

## ! (

! ( ! (

! (

 

#  \ 

# [  Proposed Site Barrick Owned Ranch Houses 

# 

  80



# 278 

# 305 

# 306 

# 766EUREKA CO.LANDER CO. 

### ELKO CO.

HUMBOLDT

Met Tower (Pipeline) 

## Carlin

Beowawe Battle Mountain

Crescent Valley 500000

500000 520000

520000 540000

540000 560000

560000 580000

5800004440000444000044600004460000448000044800004500000450000045200004520000

Datum: NAD83 UTM Zone 11N Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Com pliance\MXD\PotentialHCN102009_Fig2.mxd 

# · Barrick Cortez Mines Lander & Eureka Counties, Nevada 

# Proposed HCN Monitoring Site

Figure 2

October 14, 2009 0 5 10 15 20 25 Miles



### 0 10 20 30 40 Kilometers 

## Cortez Operations Area
Cortez Claims Boundary (AOI)
Dean Ranch (private land)

Potential HCN Source Areas

 

#  \ Climate Station 

# [  Proposed HCN Monitoring Site

## AREA 28

AREA 30 Tailings Storage Impoundment Mill Area 522000

522000 524000

524000 526000

526000 528000

52800044520004452000445400044540004456000445600044580004458000

Datum: NAD83 UTM Zone 11N Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Com pliance\MXD\PotentialHCN102009_Fig3.mxd 

# · Barrick Cortez Mines Lander & Eureka Counties, Nevada


# Potential HCN Sources Figure 3

October 08, 2009 0 2,000 4,000 6,000 8,000 10,000 Feet



### 0 400 800 1,200 1,600 2,000 2,400 2,800 3,200 Meters 

## Legend

Cortez Operations Area

Potential HCN Source Areas

### CIL Tanks CIC Tanks

Preg / Barren Tank

E. Cell Stack W. Cell Stack 523800

523800 524000

524000 524200

5242004456800445680044570004457000

Datum: NAD83 UTM Zone 11N Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Com pliance\MXD\PotentialHCNmill102009_Fig4.mxd 

# · Barrick Cortez Mines Lander & Eureka Counties, Nevada 

# Potential HCN Sources, Mill Area

Figure 4

October 08, 2009 0 200 400 600 Feet



### 0 40 80 120 160 200 Meters 

## Legend

Potential HCN Source Areas

# APPENDIX B 

# Hydrogen Cyanide (HCN) Fence Line Monitoring Plan

# Hydrogen Cyanide (HCN) Fence Line Monitoring Plan

N EVADA 

# M INING 

# A SSOCIATION

P ROJECT 

## 59-43-70 O

CTOBER 

## 2009Hcn Sampling Plan_V7.Docx 

### ii 

# CONTENTS Page

1 PROJECT MANAGEMENT ELEMENTS ................................................................................................. ...................... 1 1.1 Sampling Purpose .......................................................................................................... ........................................ 1 1.2 System Description ........................................................................................................ ......................................... 1

2 QUALITY OBJECTIVES AND CRITERIA FOR DATA MEASUREMENT ...................................................................... 3 2.1 Data Quality Objectives and Criteria ...................................................................................... ................................. 3

3 SPECIAL TRAINING REQUIREMENTS/CERTIFICATION ................................................................................. .......... 4

4 DOCUMENTATION OF RECORDS .................................................................................................... .......................... 5 4.1 Data Reporting Package Format and Documentation Control ................................................................... ............ 5

5 DATA GENERATION AND ACQUISITION ............................................................................................. ....................... 6 5.1 Sampling Process Design and Methods Requirements .......................................................................... ............... 6

5.1.1 Purpose ................................................................................................................. .......................................... 6 5.1.2 Sampling Network Design ................................................................................................. .............................. 6 5.1.3 Equipment Description ................................................................................................... ................................. 7 5.1.4 Data Logger ............................................................................................................. ........................................ 7 5.1.5 Wind Speed .............................................................................................................. ....................................... 7 5.1.6 Wind Direction .......................................................................................................... ....................................... 8 5.1.7 Temperature Sensor and Radiation Shield ................................................................................. .................... 8 5.1.8 Relative Humidity ....................................................................................................... ..................................... 8 5.1.9 Barometric Pressure ..................................................................................................... ................................... 8 5.1.10 HCN Sampling System .................................................................................................... .............................. 8 5.1.11 Power and Data Transfer ................................................................................................ ............................ 12 5.1.12 Meteorological Towers .................................................................................................. .............................. 12 5.2 Rationale for Design ...................................................................................................... ....................................... 12 5.3 Scheduled Measurement Activities .......................................................................................... ............................. 12 5.4 Measurement System Failure Response ....................................................................................... ....................... 13

6 SAMPLING METHOD REQUIREMENTS ................................................................................................ .................... 14 6.1 Sample Handling and Custody Requirements .................................................................................. .................... 14 6.2 Analytical Methods Requirements and Breakthrough Check .................................................................... ........... 14 6.3 Quality Control Requirements .............................................................................................. ................................. 14
7 INSTRUMENT/EQUIPMENT TESTING, INSPECTI ON, AND MAINTENANCE REQUIREMENTS ............................ 16

7.1 General Procedures ........................................................................................................ ...................................... 16 7.2 Instrument Calibration and Frequency ...................................................................................... ............................ 16

7.2.1 Calibration Equipment Maintenance ....................................................................................... ...................... 16 7.2.2 Calibration Records and Traceability .................................................................................... ........................ 17

8 INSPECTION/ACCEPTANCE REQUIREMENTS FOR SUPPLIES AND CONSUMABLES ....................................... 18

9 DATA MANAGEMENT ............................................................................................................. .................................... 19 9.1 Data Custody .............................................................................................................. .......................................... 19

10 DATA VALIDATION AND USABILITY .............................................................................................. ......................... 20
10.1 Data Review, Validation, and Certification ............................................................................... ........................... 20

10.1.1 Data Validation ........................................................................................................ .................................... 20 10.1.2 Data Collection ........................................................................................................ .................................... 20 10.1.3 Data Reduction ......................................................................................................... ................................... 20 10.2 Validation Methods ....................................................................................................... ...................................... 21

10.2.1 Data Review and Validation Requirements ................................................................................ ................. 21Hcn Sampling Plan_V7.Docx 

### iii 

# CONTENTS - Continued Page



## Tables
Table 1: Sensor Height on Towers ............................................................................................. ...................................... 2 Table 2: System Accuracies and Resolution .................................................................................... ................................ 3 Table 3: System Performance and Data Custody Forms ........................................................................... ...................... 5 Table 4: System Components ................................................................................................... ....................................... 6 Table 5: Sampling Frequency .................................................................................................. ...................................... 12 Table 6: Scheduled Sampling Activities ....................................................................................... .................................. 13 Table 7: Project Quality Control Checks ...................................................................................... .................................. 15
Table 8: Preventive Maintenance Schedule ..................................................................................... .............................. 16 Table 9: Calibration Equipment Testing ....................................................................................... .................................. 17
Table 10: Data Recorded on Site .............................................................................................. ..................................... 20



## Figures
Figure 1: HCN Sampling System Flow Diagram - Static Mode ..................................................................... ................... 9 Figure 2: HCN Sampling System Flow Diagram - Warm-Up Mode .................................................................... ........... 10 Figure 3: HCN Sampling System Flow Diagram - Sampling Mode Sorbent Tube 1 .................................................... .. 11



## Appendices
Appendix A: NIOSH Method 6010Hcn Sampling Plan_V7.Docx 

### 1 

## SECTION 1 

# PROJECT MANAGEMENT ELEMENTS

1.1 Sampling Purpose

This sampling plan is being developed to determine the levels of hydrogen cyanide (HCN) in ambient air at the fence line of a mine site. This plan describes the general HCN sampling equipment, collection methods, and data recording procedures. Separate site-specific plans will be submitted for individual mine sites where HCN monitoring will take place. The site-specific plans will be in accordance with this general plan unless otherwise noted, in which case the specific plan will take precedence.

There is currently no EPA method for measuring trace levels of HCN in ambient air. The method described in this monitoring plan was develope d using some elements of both EPA and NIOSH sampling and analytical guidelines. Meteorological parameters will be collected. In addition, an optional video surveillance system may be deployed to determine the operability of the sampler as well as identify any unusual conditions at the sampler.

The design of the system uses elements of U.S. EPA Quality Assurance Handbook of Air Pollution Measurement Systems Volume II as well as the NIOSH Manual of Analytical Methods, Method 6010. All meteorological parameters will be collected consistent with U.S. EPA Quality Assurance Handbook of Air Pollution Measurement System s Volume IV - Meteorological Measurements (EPA600/R94-038D), March 1995, and as provided in this plan.


# 1.2 System Description

The system will consist of a data logger connected to a low-flow pump which is connected through sorbent tubes to an ambient air inlet. The sorbent tubes will capture any HCN in the ambient air and will be sent to a certified lab for analysis. The sampling schedule will follow a 1- in-3 day calendar for a period of two months. During a run day, all parameters will be collected every two seconds and time-averaged into 15-minute values. The parameters collected are shown in Table 1. Wind speed, wind direction, ambient temperature, relative humidity, and barometric pressure are collected as well as flow rate through the sorbent tubes.

The measurement height of the inlet is two meters. The height of the wind instruments will be 3.5 meters. All other parameters are measured at 2 meters.Hcn Sampling Plan_V7.Docx 

### 2 Table 1: Sensor Height on Towers (meters above ground)



## Parameter Height Wind speed 3.5
Wind direction 3.5 Ambient temperature 2 Relative humidity 2 Barometric pressure 2 Sampler Flow 2Hcn Sampling Plan_V7.Docx 

### 3 

## SECTION 2 

# QUALITY OBJECTIVES AND CRITERIA FOR DATA MEASUREMENT

2.1 Data Quality Objectives and Criteria

The primary quality objectives are taken from EPA guidance where applicable. The following tables present the guidelines for each sensor as well as the relevant references for each.

Table 2: System Accuracies and Resolution

Parameter Sensor* Range Accuracy Standard Measurement
Resolution Reference

Wind direction R.M. Young 05305-AQ Range: 0 ° to 360 ° + 3 ° Accuracy:

+ 5 ° 1.0 ° EPA-454/4-87-007 Section 6.1.1, EPA-454/R-99-005, February 2000, Table 5-1 Wind speed R.M. Young 05305-AQ 0.4 to 45 m/s + 0.2 m/s Accuracy:

+ 0.25 m/s

up to speeds of 5

m/s and

+ 5% thereafter 0.1 m/s EPA-454/4-87-007 Section 6.1.1 EPA-454/R-99-005, February 2000, Table 5-1

Ambient temp. Campbell Scientific Model HMP45C -39.2 ° C to +60 ° C + 0.3 ° + 0.5 ° C 0.1 ° C EPA-454/4-87-007 Section 6.1.5 EPA-454/R-99-005, February 2000, Table 5-1 Relative humidity Campbell Scientific Model HMP45C 0.8 to 100% + 2% (0-90% RH) and

+ 3% (90- 100% RH) 1.5 ° C dew point temperature

error 1% EPA-454/4-87-007 Section 6.1.4 EPA-454/R-99-005, February 2000, Table 5-1
Barometric
pressure Vaisala PT101B -40 ° C to 60 ° C + 0.5 mb + 3 mb + 0.1 mb EPA-454/4-87-007 Section 6.1.7 EPA-454/R-99-005, February 2000, Table 5-1 Flow rate Pressure transducer N/A + 5% + 10% of observed 0.1 l/min N/A

* Or equivalent sensor.Hcn Sampling Plan_V7.Docx 

### 4 

## SECTION 3 

# SPECIAL TRAINING REQUIREMENTS/CERTIFICATION

The monitoring equipment should be operated unde r the guidance of the Project Technician. The Project Technician will receive training in the equipment operation. Any non-routine work on this system must be conducted by a qualified technician.Hcn Sampling Plan_V7.Docx 

### 5 

## SECTION 4 

# DOCUMENTATION OF RECORDS

All of the forms which will be used to document the system performance and data custody are
listed in Table 3.

Table 3: System Performance and Data Custody Forms



## Component Hard Copy or Electronic Copy Comments Site Check Form Hard Copy Include check of flow and meteorological sampling. Chain of Custody Form Hard Copy Record handling of sorbent tube through analytical process. Site-Specific Journal Record Hard Copy and Electronic Copy Record any anomalous

occurrences. Flow Audit Hard Copy and Electronic Copy Conduct at end of 2 month sampling period.



# 4.1 Data Reporting Package Format and Documentation Control

A report will be prepared and submitted to EPA within 30 days of the conclusion of the data collection program. The report will contain:

• A calculation of the percentage of valid data collected with an explanation of any instrument malfunction for each parameter,

• All valid hourly meteorological data,

• All valid flow data,

• All HCN concentrations determined by laboratory analysis,

• Copies of Site Check Forms,

• Copies of any calibrations and audits performed,

• Anecdotally conveyed no tes and anomalies, and

• Corrective actions taken (if any).
After the first four weeks of sampling, prelim inary data will be supplied to EPA after the analyses are received from the laboratory.Hcn Sampling Plan_V7.Docx 

### 6 

## SECTION 5 

# DATA GENERATION AND ACQUISITION

5.1 Sampling Process Design and Methods Requirements 5.1.1 Purpose
The monitoring requirements subject to EPA an d federal guidelines are strictly defined for meteorology but not for HCN. The equipment se lection and operation of the station is in accordance with available guidelines. In cases where an existing meteorological station at the mine meets all applicable guidelines, this station may be used in lieu of the meteorological equipment specified herein. The site-specific pl an submitted by each mine will address the proposed location of the meteorological monito ring station that will be used to provide meteorological data for the ambient fence line monitoring program.


# 5.1.2 Sampling Network Design
The monitoring system will consist of the following parts, or equivalent, as specified in the sitespecific plan. Each part will have a serial number and will be calibrated upon installation.

Table 4: System Components



## Item Manufacturer Model Name Enclosure Campbell Scientific ENC 12/14 3-meter tower Campbell Scientific 25G Wind sensor mount Campbe ll Scientific 019ALU Pyranometer mounting arm Campbell Scientific 015ARM Data logger CR3000 Campbell Scientific CR23X or CR10X Power supply with battery Ca mpbell Scientific PS12LA Solar panel Campbell Scientific MSX10R

Wind sensor R.M. Youn g Wind Monitor 05305-AQ Wind sensor cable R.M. Young Solar power system Kyocera Solar Electric System Temperature and relative humidity

sensor Campbell Scientific HMP45C

Barometric pressure sensor Vaisala PT101B

Flow meter Newark Electronics TE525

Flow meter Newark Electronics Pressure TransducerHcn Sampling Plan_V7.Docx 

### 7 

# 5.1.3 Equipment Description
The following section describes the air quality and meteorological instrumentation that will be used for the HCN monitoring program. The inst rumentation is selected consistent with the requirements of:

• U.S. EPA Quality Assurance Handbook of Air Pollution Measurement Systems Volume II, September 1997.

• NIOSH Manual of Analytical Methods, Method 6010, August 1994

.

• U.S. EPA Quality Assurance Handbook of Air Pollution Measurement Systems Volume IV - Meteorological Measurements (EPA-454/B-08-002), March 2008.
The data collection systems are designed to ex ceed the recommended quarterly data recovery rate of 90 percent for all meteorological parameters and 75 percent for HCN.


# 5.1.4 Data Logger
A Campbell Scientific, Inc. Model CR3000 data logger is used as the digital acquisition system for the stations. The data logger records the data every two seconds, computes 15-minute averages of each of the meteorological parameters, and stores the averages in its internal memory. The CR3000 has 4 mB of Flash Electrically Erasable Programmable Read Only Memory (EEPROM) for the operating system and user programs. It also has 512K of Static Random Access Memory (SRAM) used for storing approximately three months of data and running the program. It has a
16-bit micro-controller with 32-bit internal CPU ar chitecture. The resolution and accuracy of the analog inputs are 6.67 microvolts and ± 0.04%, respectively. The CR3000 is equipped with a solidstate storage module. The 15-minute averages are written to the CR3000's internal memory and to the external storage module. The storage module can store nearly six mo nths of data and will provide a backup of the data and the CR3000 prog ram in the unlikely event of a power loss. The data logger is designed to operate in temperatures from –25 ° C to 50 ° C.


# 5.1.5 Wind Speed
Wind speed is continuously measured using an R.M. Young Model 05305 sensor interfaced directly to the data logger. The wind speed sens or of the Model 05305 is a helicoid-shaped, fourblade propeller. Rotation of th e propeller produces an AC sine wave; the frequency is directly proportional to the wind speed. The AC signal is induced in a transducer coil by a six-pole magnet mounted on the propeller shaft. The coil is located on the non-rotating central portion of the main mounting assembly, eliminating the need for slip rings and brushes. Power for the sensor is supplied by the data logger. The Model 05305 has a range of 0.4 - 45 m/s, a starting threshold of 0.4 m/s, an accuracy of 0.2 m/s, and a distance constant of 2.1 meters.Hcn Sampling Plan_V7.Docx 

### 8 

# 5.1.6 Wind Direction
Wind direction is also continuously measured using an R.M. Young Model 05305 sensor interfaced directly to the data logger. The Model 05305 sensor provides a 1 ° to 360 ° format through the use of a precision potentiometer powered by the data logger. The potentiometer outputs a varying voltage proportional to the wind direction in degrees. The sensor is constructed from lightweight thermoplastic materials to give it a starting threshold of less than 0.5 m/s. The sensor has an accuracy of ±3 ° , a damping ratio of 0.45, and a delay distance of less
than 2 meters.


# 5.1.7 Temperature Sensor and Radiation Shield
The temperature measurements are continuously monitored using a Campbell Scientific HMP45C Platinum Resistance Temperature (PRT) detector. Temperature is measured by the data logger as a varying resistance across a platin um resistor that is proportional to the ambient temperature. The range of the sensor is –40°C to +60°C. The radiation shield for the temperature sensor prevents interference from solar radiatio n. The radiation error is less than 0.1°F.


# 5.1.8 Relative Humidity
Relative humidity is continuously measured using a Campbell Scientific Model HMP45C sensor.
The HMP45C contains a Vaisala HUMICAP TM 

## 180 capacitive relative humidity sensor. The HMP45C sensor is housed inside a non-aspirated shield. Relative humidity is measured by the data logger as an output voltage. The range of the sensor is from 0.8 to 100% (non-condensing) with an accuracy of ±2% when the humidity is less than 90%, and ±3% when the humidity is greater than 90%. The response time for th e relative humidity sensor is 15 seconds.



# 5.1.9 Barometric Pressure
Barometric pressure is measured every 15 minute s using a Vaisala PT101B sensor. The sensor is mounted inside the data logger enclosure. Barome tric pressure is measured by the data logger using Vaisala’s Barocap silicon capacitive pressu re sensor, which outputs a linear 0 to 2.5 VDC signal. The operating range of the sensor is –40 ° C to 60 ° C. The CS105 has a warm-up time of one second, an uncertainty of 0.15 millibar, and a linearity of 0.45 millibar.


# 5.1.10 HCN Sampling System
This instrument is designed to measure HCN at trace levels in ambient air. There is currently no
EPA certified method for this determination. Th e design combines elements of EPA air quality measuring guidelines along with NIOSH sampling protocols. The sampler consists of soda lime sorbent tubes (SKC part number 226-28) connected to a glass inlet. On the other side of the sorbent tubes is a low flow pump controlled by a data logger via a feedback loop with a pressure transducer. The flow is regulated by a critical orifice, and ambient meteorological parameters are collected to determine the exact volume of gas pass ed through the sorbent tubes. Data collection is in twenty-four hour increments. Upon complete exposure of a sorbent tube, it is sealed andHcn Sampling Plan_V7.Docx 

### 9 

## shipped to a certified laboratory for analysis in accordance with NIOSH Method 6010. The complete NIOSH Method 6010 is included as Appendix A.



## 5.1.10.1 Operating Principle
As discussed above, the HCN sampling system consis ts of an open-air inlet, sorbent tubes, and a pump which pulls air through the sorbent tubes at a rate of 1 liter per minute. The system is designed to hold two or more sorbent tubes, where each tube will collect a 24-hour sample. Based on the 1-in-3 day schedule, a site visit to change out the tubes will be required every 5-7 days (or longer if more than two tubes are design ed into the system). The total volume of air pulled through each sorbent tube is 1,440 liters. This exceeds the recommended total volume of NIOSH Method 6010 but is within the capture volu me of the sorbent tube and necessary to reach the required limits of detection.

A data logger turns the pump on and off and cont rols the solenoid valve according to the 1-in-3 day schedule. The solenoid valve opens and closes to allow air to pass through a sorbent tube only during a run day. The data logger al so records ambient barometric pressure and temperature to calculate the volume of air passed through the sorbent tube during the run day. Flow diagrams of the HCN sampling system, show ing the system in static mode, warm-up mode, and sampling mode, are provided in Figures 1 through 3.

Figure 1: HCN Sampling System Flow Diagram - Static Mode

INLET

SOLENOID VALVE



### SORBENT TUBE 1



### PRESSURE TRANSDUCER

PUMP

POWER RELAY 

### POWER 

### OUTLET DATA LOGGER

BAROMETRIC PRESSURE

TEMPERATURE 

### SORBENT TUBE 2



### CHECK VALVE 

### CALIBRATION VALVEHcn Sampling Plan_V7.Docx 

### 10 Figure 2: HCN Sampling System Flow Diagram - Warm-Up Mode

INLET

SOLENOID VALVE



### SORBENT TUBE 1



### PRESSURE TRANSDUCER

PUMP

POWER RELAY 

### POWER 

### OUTLET DATA LOGGER

BAROMETRIC PRESSURE

TEMPERATURE 

### SORBENT TUBE 2



### CHECK VALVE 

### CALIBRATION VALVEHcn Sampling Plan_V7.Docx 

### 11 Figure 3: HCN Sampling System Flow Diagram - Sampling Mode Sorbent Tube 1



## On a run day, at 15 minutes before the sampling commences, the data logger turns the pump on and switches the solenoid valve to allow air to flow around the sorbent tubes and through the pump. This gives the pump time to warm up and ensures that the air in the inlet is homogenous when the sampling begins. To initiate sampling, the data logger switches the solenoid valve to allow air to flow through the first sorbent tube an d the sampling begins. After 24 hours, the data logger closes the solenoid valve, stopping flow to the sorbent tube, and turns the pump off. On the next run day, after the warm-up period, to initiate sampling, the data logger switches the solenoid valve to allow air flow through the second sorbent tube. After 24 hours, the data logger closes the solenoid valve, stopping flow to the second sorbent tube. The tubes are replaced before the next run day and the sampling process repeats.

After the 24-hour sampling is complete, each sorbent tube is sealed and shipped to a certified laboratory where the HCN is extracted and anal yzed using spectroscopy. One in every five
sorbent tubes will be a field bl ank. The blank tubes will follow the same path as the sampled tubes, with the exception of being inserted into the sampling system. INLET

SOLENOID VALVE



### SORBENT TUBE 1



### PRESSURE TRANSDUCER

PUMP

POWER RELAY 

### POWER 

### OUTLET DATA LOGGER

BAROMETRIC PRESSURE

TEMPERATURE 

### SORBENT TUBE 2



### CHECK VALVE 

### CALIBRATION VALVEHcn Sampling Plan_V7.Docx 

### 12 

## The detection limit for this HCN sampling method is reported to be approximately 0.2 ppb 1



## , which is an order of magnitude less than the EPA reference concentration of 2.8 ppb.



# 5.1.11 Power and Data Transfer
Solar power is used to operate the equipment. The data logger is powered separately via a smaller solar cell to prevent total data and commu nications loss during periods of power loss. A cellular Internet modem is installed providing real-time satellite communications.


# 5.1.12 Meteorological Towers
A 10-foot Rohn 25G meteorological tower will be installed for the purpose of mounting the sensors. The tower will be grounded, and lightning protection will be installed on all signal lines.


# 5.2 Rationale for Design

The equipment has been selected based on its conformity to current EPA standards for meteorology and current NIOSH standards for HCN monitoring.



# 5.3 Scheduled Measurement Activities

The sampler pump will be activated on 1-in-3 da y schedule. During this period all parameters, with the exception of HCN concentration, will be collected every two seconds. This is
summarized in Table 5 and Table 6.

Table 5: Sampling Frequency



## Parameters Engineering
Units Sampling Rate Averaging Rate Number of Samples per
24-Hour Period Wind speed Meters/second Every 2 seconds Every 15 minutes 96 Wind direction Degrees Every 2 seconds Every 15 minutes 96
Ambient temperature and relative humidity Degrees Celsius and percent Every 2 seconds Every 15 minutes 96

Barometric
pressure Millibar Every 2 seconds Every 15 minutes 96

HCN sampler flow Liters/minute Every 2 Seconds Every 15 minutes 96
HCN concentration* Parts per billion Every 24 hours Every 24 hours 1

*HCN concentration can only be determined upon completion of laboratory analysis.

1 Kenneth G. Orloff et al., Hydrogen cyanide in ambient air near a gol d heap leach field: Measured vs. modeled concentrations, Atmospheric Environment, 2006, p. 3023.Hcn Sampling Plan_V7.Docx 

### 13 Table 6: Scheduled Sampling Activities



## Activity Frequency Required Personnel
Site Check Every 5-7 days Maintenance Technician Calibration At installation Project Technician
Flow Audit At close out Auditor



# 5.4 Measurement Syst em Failure Response

The primary mechanism for ensuring normal sy stem operation will be comprised of on-site checks conducted after the tubes have been sample d and before the next run day. The site check schedule will be every 5-7 days (or longer if more than two tubes are designed into the system). The Maintenance Technician is responsible for on-site checks and completion of Site Check Forms. Any issues that are detected during the site checks will be resolved as soon as possible.

If a run day sampling is missed or incomplete, a substitute 24-hour sampling can be used if it is completed before the next scheduled run day.Hcn Sampling Plan_V7.Docx 

### 14 

## SECTION 6 

# SAMPLING METHOD REQUIREMENTS

6.1 Sample Handling and Custody Requirements

A new sorbent tube will be inserted into the sampler system prior to midnight of a run day. After completion of the run, the sorbent tube will be removed and prepared for shipment to a certified lab. All sorbent tubes used for sampling will be tracked in a Chain of Custody Form.


# 6.2 Analytical Methods Requi rements and Breakthrough Check

The sample will be digested at the lab and a coloring agent will be added to make the cyanide spectroscopically active. UV/Vis spectroscopy will be employed to determine the cyanide concentration. The quantity of cyanide present will be combined with the known flow of the sample exposure to generate a 24-hour HCN sample concentration. The analysis will be
conducted in accordance with NIOSH Me thod 6010 (included as Appendix A).

As part of the HCN analysis, each tube will be checked for breakthrough. The sorbent tubes
consist of a front half and back half. Each half will be analyzed separately to determine the mass of cyanide. Any sample where the mass of cyanid e in the back half is greater than one-tenth of the mass of cyanide in the front half will be flagged indicating that breakthrough has occurred.


# 6.3 Quality Control Requirements

Quality control for the program will be affected through the use of site checks, post-installation calibration, and close out audits. Information pr ovided by each of these methods is documented
in the Table 7 below.Hcn Sampling Plan_V7.Docx 

### 15 Table 7: Project Quality Control Checks



## QC Check Information Provided Frequency Site Checks All information about the station status, which cannot be determined from the raw data. Additionally, it provides real-time data for comparison with hourly averages to insure that station is functioning within prescribed guidelines. Every 5-7 days

Calibrations Determines the serviceability, accuracy, and precision of the equipment operating on site. Sensors are tested over a full range of operating conditions to ensure that they are performing within prescribed guidelines. At installation

Flow Audit Determines the serviceability, accuracy, and precision of the equipment operating on site. Sensors are tested over a full range of operating conditions to ensure that they are performing within prescribed guidelines. At close outHcn Sampling Plan_V7.Docx 

### 16 

## SECTION 7 

# INSTRUMENT/EQUIPMENT TESTING, INSPECTION, AND MAINTENANCE REQUIREMENTS

The sensor/equipment maintenance schedule is based on the manufacturer’s guidelines. All routine maintenance tasks will be accomplishe d by the Project Technician. In addition, preventive maintenance tasks are summarized in Table 8.

Table 8: Preventive Maintenance Schedule



## Parameter Sensor Replacement Frequency
Wind speed and direction R.M. Young 05305-AQ Every 2 years.
Temperature/relative humidity Campbe ll Scientific HMP45C Every 2 years.
Barometric pressure Vaisala PT101B Every 2 years. Sampling pump SKC Low Flow Pump to be refurbished annually.

*Due to the duration of the sampling program, it is anticipated that preventive maintenance will not be needed.



# 7.1 General Procedures

The Project Technician will review the Site Chec k Forms and compare them to the 15-minute data
averages to ensure proper syst em operation and data transfer.


# 7.2 Instrument Calibration and Frequency

The following section outlines the preventive ma intenance/recalibration of the equipment used to test the performance of the on-site systems.


# 7.2.1 Calibration Eq uipment Maintenance
The identity, frequency, and governing standard for all calibration equipment can be found in
Table 9.Hcn Sampling Plan_V7.Docx 

### 17 Table 9: Calibration Equipment Testing



## Parameter Calibration Equipment Calibration Frequency Reference Wind speed Anemometer Drive 200 to 15,000 RPM Biannually EPA 600/R-94/038D, Section 4.2.2 Wind direction Degree Wheel N/A EPA 600/R-94/038D, Section 4.2.2 Temperature Temperature Standard Annually EPA 600/R-94/038D, Section 4.3.2 Barometric pressure Altimeter N/A EPA 600/R-94/038D, Section 4.6 Relative humidity Collocated HMP45C Biannually EPA 600/R-94/038D, Section 4.6 Data logger Voltmeter Annually EPA 600/R-94/038D, Section 4.1.4.1 Flow Flow Meter Annually N/A

The equipment supplier will be required to maintain calibration equipment certifications in hard

copy.



# 7.2.2 Calibration Reco rds and Traceability
Calibration Forms are completed and maintained by project personnel. All Calibration Forms indicate the sensor calibrated, its serial numb er, the date calibrated, and any other pertinent information/anomalies.Hcn Sampling Plan_V7.Docx 

### 18 

## SECTION 8 

# INSPECTION/ACCEPTANCE REQUIREMENTS FOR SUPPLIES AND CONSUMABLES

The only consumable used in this process is the sorbent tubes. All tubes will be inspected upon receipt. Any tubes which show signs of physical damage will be discarded. Documentation sent with the maintenance items are kept on file as they apply to each sensor and its serial number.Hcn Sampling Plan_V7.Docx 

### 19 

## SECTION 9 

# DATA MANAGEMENT

The data will be collected and stored in the da ta logger and backed up in the on-site storage module. The data can be automatically or manually transferred to the user’s database. The data will then be quality controlled/quality assura nce checked (QA/QC’d) and stored on a server.


# 9.1 Data Custody

Data retrieval, quality control, and processing will be documented. Site Check Forms and all other program documentation will be archived. Additionally, a journal will be kept to record any
anomalous occurrences.Hcn Sampling Plan_V7.Docx 

### 20 

## SECTION 10 

# DATA VALIDATION AND USABILITY

10.1 Data Review, Validation, and Certification
10.1.1 Data Validation
The data will be reviewed, quality controlled/quality assurance checked (QA/QC’d), and validated in accordance with EPA guidelines.



# 10.1.2 Data Collection
Data received from the site will consist of 15-minute averages for all parameters. A complete list of parameters from the site can be found in Table 10.

Table 10: Data Recorded on Site



## Parameter Units Frequency Array ID N/A Every 15 minutes Year -- Every 15 minutes Day Julian Day Every 15 minutes Time Hour/Minute Every 15 minutes Wind speed Meters/Second Every 15 minutes Wind direction Degrees from Every 15 minutes
Wind direction standard devi ation None Every 15 minutes Barometric pressure Millibar Every 15 minutes Relative humidity Percent Every 15 minutes Ambient temperature Degrees Celsius Every 15 minutes Data logger battery voltage DCV Every 15 minutes SIN wind direction None Every 15 minutes COSINE wind direction None Every 15 minutes Flow l/min. Every 15 minutes



# 10.1.3 Data Reduction
On-site data is collected every two seconds and pl aced into temporary storage. Every 15 minutes the data is reduced and stored in the ring memory of the data logger. The wind speed, temperature, relative humidity, barometric pressure, and flow data are reduced as scalar averages using the equation below.


# ∑

= N

i 

# u N u

1 

# 1

The wind direction data is reduced as a unit vector according to the following equations.Hcn Sampling Plan_V7.Docx 

### 21 

# ∑

= N

i S 

# Sin N V

1 

# 1 θ



# ∑

= N

i C 

# Cos N V

1 

# 1 θ



# X V V ArcTan

C S 

# + ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛

= θ

If Vc < 0 then X = +180 If Vs < 0 then X = +360 If Vs > 0 then X = +0

The wind direction deviation is reduced using the Yamartino algorithm found below. 

# ( ) ( ) 

# [ ] 3 

# 1547

. 0 1 1 ε ε θ σ + = ArcSin

where, 

# () () 

# ( ) 

# [ ] 2 1 2 2 

# 1 C S 

# V V +

− = ε

and Vs and Vc are as defined above.

After the 15-minute data has been downloaded, it is processed into one-hour averages using the same equations listed above.



# 10.2 Validation Methods
10.2.1 Data Review and Validation Requirements
The data review and validation requirements follow the protocols outlined in Section 5 of this monitoring plan. The validation is accomplished by using quality control standards based on federal and manufacturer’s guidelines as well as expected sampler performance. If a quality control standard is not met, the data will be flagged initially, and the causes immediately investigated. All data, which is found to be invali d, will be removed from the data set. All data, which is subsequently proven to be valid, will be processed for inclusion in the reports.

# APPENDIX A 

# NIOSH Method 6010

# HYDROGEN CYANIDE 6010



# HCN MW: 27.03 CAS: 74-90-8 RTECS: MW6825000

METHOD: 6010, Issue 2 EVALUATION: FULL Issue 1: 15 May 1989 Issue 2: 15 August 1994

OSHA : 10 ppm (skin) NIOSH: STEL 4.7 ppm ACGIH: C 10 ppm (skin)

(1 ppm = 1.105 mg/m 3 @ NTP) PROPERTIES: gas; BP 26 °C; vapor density 0.93 (air = 1.00); d(liq) 0.69 g/mL @ 20 °C; VP 82.7 kPa (620 mm Hg) @ 20 °C; explosive range 5 to 40% v/v in air

SYNONYMS: hydrocyanic acid, prussic acid, formonitrile

SAMPLING

SAMPLER: SOLID SORBENT TUBE

(soda lime, 600 mg/200 mg)

FLOW RATE: 0.05 to 0.2 L/min

VOL-MIN: 2 L @ 5 ppm
-MAX: 90 L

SHIPMENT: routine

SAMPLE STABILITY: at least 2 weeks @ 25 °C [1]

BLANKS: 2 to 10 field blanks per set MEASUREMENT

TECHNIQUE: SPECTROPHOTOMETRY,

VISIBLE ABSORPTION

ANALYTE: cyanide ion complex

DESORPTION: 10 mL deionized water; stand 60 min

COLOR DEVELOPMENT: N-chlorosuccinimide/ succinimide oxidizing agent and barbituric acid/pyridine coupling agent; absorption @ 580 nm in 1-cm cuvette

CALIBRATION: standard solutions of KCN in 0.1 N NaOH

RANGE: 10 to 300 μg CN - per sample [1]

ESTIMATED LOD: 1 μg CN - per sample [1]

PRECISION ( S r ): 0.041 @ 10 to 50 mg per sample [1] ACCURACY

RANGE STUDIED: 2 to 15 mg/m 3 [1] (3-L samples)

BIAS: Not significant

OVERALL PRECISION ( S ˆ rT ): 0.076 [1]

ACCURACY: ± 15.0%

APPLICABILITY: The working range is 0.3 to 235 ppm (3 to 260 mg/m 3 ) for a 3-L air sample. This method is applicable to STEL measurements. Particulate cyanides are trapped by the initial glass fiber membrane disk. This method is more sensitive a nd subject to fewer interferences than NIOSH Method 7904, which uses ion specific electrode analysis. The method was used t o determine HCN in firefighting environments [2].

INTERFERENCES: A high concentration of hydrogen sulfide gives a negative interference.

OTHER METHODS: This is based on the method of Lambert, et al. [3]. NIOSH Method 7904 uses an ion specific electrode for measurement. The method has been adapted for use with a Technicon Autoanalyzer [4].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94

## HYDROGEN CYANIDE: METHOD 6010, Issue 2, dated 15 August 1994 - Page 2 of 5

SAMPLING: REAGENTS:

1. Potassium cyanide*, reagent grade. 2. Succinimide, reagent grade. 3. N-Chlorosuccinimide, reagent grade. 4. Barbituric acid, reagent grade. 5. Pyridine, spectrophotometric quality. 6. Phenolphthalein, 1% (w/v) in ethanol or methanol, reagent grade. 7. Hydrochloric acid, concentrated, reagent grade. 8. Sodium hydroxide (NaOH), reagent grade.* 9. Sodium lime (CaO + 5-20% NaOH), reagent grade (Aldrich #26,643-4 or equivalent). Crush and sieve to 10/35 mesh. Store in capped container.* 10. Water deionized-distilled. 11. Sodium hydroxide solution, 0.1 N .* 12. Calibration stock solution. 1 mg /mL CN -



## . Dissolve 0.125 g KCN in 0.1 N NaOH in a 50- mL volumetric flask. Dilute to mark with 0.1 N NaOH. Standardize by titration with standard AgNO 3 

## solution (see APPENDIX). 13. Hydrochloric acid solution, 0.15 N

. 14. N-Chlorosuccinimide/succinimide oxidizing reagent. Dissolve 10.0 g succinimide in about 200 mL distilled water. Add 1.00 g Nchlorosuccinimide. Stir to dissolve. Adjust volume to 1 liter with distilled water. Stable 6 months when refrigerated. 15. Barbituric acid/Pyridine reagent. Add about 30 mL distilled water to 6.0 g barbituric acid in a 100-mL Erlenmeyer flask. Slowly add 30 mL pyridine with stirring. Adjust the volume to 100 mL with water. Stable 2 months when refrigerated. EQUIPMENT:

1. Sampler, glass tube, 9 cm long, 7-mm OD, 5-mm ID, with plastic caps, containing two sections (front = 600 mg; back = 200 mg) granular soda lime 10/35 mesh, separated and contained with silanized glass wool plugs, with a 5-mm diameter glass fiber filter disk placed before the plug on inlet side. Tubes are commerically available. (SKC, Inc. 226-28 or equivalent.) 2. Spectrophotometer, visible, 580 nm, with cuvettes, 1-cm light path. 3. Personal sampling pump, 0.05 to 0.2 L/min, with flexible connecting tubing. 4. Pipets, volumetric 0.1-, 0.5-, 1.0-, 2.0-, 10.0-mL. 5. Vials, glass or plastic, 15-mL with PTFE-lined
caps. 6. Flasks, volumetric, 25-, 50-, 100-, 1000-mL, with stoppers. 7. Pipets, transfer, disposable. 8. Syringes, 10-μL, readable to 0.1 μL. 9. Flask, Erlenmeyer, 100-mL. 10. Syringes, 10-mL, polyethylene with luer tip. 11. Filter cassette, with membrane filter, 13-mm diameter, 0.45-μm pore size, with luer fitting.

* See SPECIAL PRECAUTIONS

SPECIAL PRECAUTIONS: HCN gas and cyanide particulates are highly toxic and may be fatal if swallowed, inhaled, or absorbed through the skin [5]. Soda lime and NaOH are very caustic [5]. Use gloves and a fume hood for handling these chemicals. 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Break ends of sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. 3. Sample at an accurately known flow rate between 0.05 and 0.2 L/min for a total sample size of 0.6 to 90 L. 4. Cap tube. Pack securely for shipment.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94

## HYDROGEN CYANIDE: METHOD 6010, Issue 2, dated 15 August 1994 - Page 3 of 5

SAMPLE PREPARATION:

5. Score each sampler with a file. Break sampler at score line. 6. Transfer front and back sorbent sections to separate vials. Discard glass wool plugs separating and retaining sorbent sections. NOTE: An estimate of particulate cyanide may be obtained by analyzing the initial glass fiber filter disk as follows; however, no evaluation data are available for particulate cyanides determined in this manner. (i) Transfer the glass wool plug at the tube inlet and the glass fiber filter disk immediately behind it to a third vial. (ii) Add 10.0 mL 0.1 N NaOH to each vial. (iii) Proceed with step 8. 7. Add 10.0 mL deionized-distilled water to each vial containing a sorbent section. Cap each vial. 8. Allow to stand 60 minutes, with occasional agitation. Transfer to a 10-mL plastic syringe fitted with an in-line 0.45-μm filter. Collect the filtrate in a clean vial.

CALIBRATION AND QUALITY CONTROL:

9. Calibrate daily with at least six working standards over the range 1 to 300 μg CN - 

## per sample.

a. Prepare a working standard solution, 1.00 μg /mL.CN - 

## , by diluting 100 μL of calibration stock solution to 100 mL with 0.1 N NaOH. b. Pipet 0.5-, 1.00-, 1.50-, 2.00- and 2.50-mL of the working standard solution into 25-mL volumetric flasks to make 0.50-, 1.00-, 1.50-, 2.00- and 2.50- μg CN - 

## standards.

c. Analyze together with field samples and blanks (steps 12 through 19). d. Prepare calibration graph (absorbance vs. μg CN - 

## ). 10. Determine desorption efficiency (DE) at least once for each lot of soda lime used for sampling. Prepare at least three tubes at each of five levels plus three media blanks.

a. Remove and discard back sorbent section of a blank sampler. b. Inject a known amount of calibration stock solution directly onto the soda lime with a microliter syringe.

c. Cap, and allow to stand overnight. d. Desorb (steps 5 through 8) and analyze together with working standards and blanks (steps 12 through 19).

e. Prepare a graph of DE vs. μg CN - 

## recovered. 11. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and DE graph are in control.

MEASUREMENT:

12. Set spectrophotometer according to manufacturer's recommendations and to conditions on p. 6010-1. 13. Pipet a sample aliquot estimated to contain 0.5 to 2.5 μg CN - 

## into a 25-mL volumetric flask. Alternately, to cover an unknown sample concentration range, pipet 0.5-, 1.00-, and 3.00-mL aliquots into separate 25-mL vol. flasks for each field sample. Larger or smaller aliquots may be taken, based on prior knowledge of expected analyte level. 14. Pipet 0.5 mL 0.1 N NaOH into a 25-mL volumetric flask for reagent blank. 15. Add one drop phenolphthalein solution to each standard or sample. NOTE: Add a little deionized-distilled water to increase volume for easier mixing. All solutions should be alkaline (pink) at this point. 16. Starting with the reagent blank, add dropwise 0.15 N HCl, with mixing, until pink color just disappears. CAUTION: HCN may be produced. Work in hood. Immediately add 1.0 mL N-chlorosuccinimide/succinimide oxidizing reagent. Mix and let stand.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94

## HYDROGEN CYANIDE: METHOD 6010, Issue 2, dated 15 August 1994 - Page 4 of 5

NOTE 1: To avoid possible loss of HCN, add the oxidizing agent before proceeding to the

next sample. NOTE 2: Do not prepare more samples than can be analyzed within the 30-minute maximum

time for color development. 17. After at least 5 min. standing (but not longer than 15 min), starting with the reagent blank, add 1.0-mL barbituric acid-pyridine coupling reagent. Mix. 18. Adjust sample volume to 25 mL with deionized-distilled water and allow to stand at least 12 min (but not longer than 30 min) for color development. 19. Read absorbance at 580 nm in a 1-cm light path cuvette on a spectrophotometer. If sample absorbance is outside the range of the calibration standards, take an aliquot, re-analyze (steps 12 through 19), and apply the appropriate aliquot factor in calculations.

CALCULATIONS:

20. Calculate the mass, μg, of CN - 

## in aliquot analyzed. Apply the appropriate aliquot factor to calculate the mass, μg, of CN - 

## in the original 10-mL solution. 21. Determine the mass, μg CN - 

## (corrected for DE), found in the sample front (W f 

## ) and back (W b 

## ) sorbent sections and in the average media blank front (B f 

## ) and back (B b 

## ) sorbent sections. If W b 

## > W f 

## /10, report breakthrough and possible sample loss. 22. Calculate concentration, C, of HCN in the air volume sampled, V(L).

where 1.039 = conversion factor, CN - 

## to HCN

EVALUATION OF METHOD:

The method was evaluated by sampling the test atmospheres of HCN generated from a compressed mixture of HCN in nitrogen [1]. The range of HCN concentration was equivalent to 2 to 15 mg/m 3 

## for a 3-L air sample. Twenty-two samples collected at 0.2 L/min for 15 minutes indicated overall precision S ˆ rT 

## of 0.076 with nearly 100% recovery. Breakthrough occurred after 40 minutes of sampling at the flow rate of 0.2 L/min at an HCN concentration of 148 mg/m 3 

## . Sample tubes spiked with solutions of KCN and analyzed after storage, indicated that the samples of cyanide ions were stable on the tube for at least 2 weeks. Analysis of 22 tubes which were spiked with KCN standard solutions in the range 10 to 50 μg indicated a recovery of nearly 100% with a pooled precision of 0.041. Desorption efficiency may be poor below 10 μg CN - 

## [6].

REFERENCES:

[1] Williamson, George. "Method Development Protocol and Backup Data Report on Hydrogen Cyanide" Internal NIOSH/MRSB Report, Unpubl. NIOSH (1988). [2] Williamson, George. "Analysis of Air Samples on Project 166 (Firesmoke) on HCN; Sequence NIOSH/MRSB-6366A, Unpubl. NIOSH, (1988). [3] Lambert, J. L., Ramasamy, J., and J. V. Paukstelis, "Stable Reagents for the Colorimetric Determination of Cyanide by Modified Konig Reactions," Analyt. Chem.

, 47 , 916-918 (1975). [4] DataChem Laboratories, NIOSH Sequence #6837-K (unpublished, March 21, 1990). [5] NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards, U.S. Department of Health and Human Services. Publ. (NIOSH) 81-123 (1981), available as stock #PB 83-154609 form NTIS, Springfield, VA 22161. [6] DataChem Laboratories, User Check, NIOSH Sequence #6837-J (unpublished, March 19, 1990).

METHOD WRITTEN BY: George Williamson, NIOSH/DPSE.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94

## HYDROGEN CYANIDE: METHOD 6010, Issue 2, dated 15 August 1994 - Page 5 of 5

APPENDIX: STANDARDIZATION OF CALIBRATION STOCK SOLUTION

Titrate an aliquot of the cyanide standard stock solution (Reagent 12) with standard silver nitrate (AgNO 3 

## ) solution. The end point is the first formation of a white precipitate, Ag[Ag(CN) 2 

## ]. Calculate the cyanide concentration with the following equation:

M
c 

## = 52.04 V
a 

## (M
a 

## /V
c 

## )

Where M
c



## = cyanide concentration (mg/mL) V
a 

## = volume (mL) of standard silver nitrate solution M
a 

## = concentration (moles/L) of standard silver nitrate solution V
c 

## = volume (mL) of calibration stock solution titrated

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94