Meteorological and 

Hydrogen Cyanide 

(HCN) Fence Line 

Monitoring Report 

BARRICK CORTEZ, INC. 

PROJECT 59-52-10 

JANUARY 2010 
Draft_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 ANALYSIS ..................................................................................................................................................... 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 Plans 
Draft_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 taken 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 performed in accordance with the U. S. EPA Quality 

Assurance Handbook of Air Pollution Measurement Systems Volume IV - Meteorological Measurements 

(EPA-600/R94-038D), March 1995. 

Cortez operates a gold mining facility located approximately 38 miles south of Interstate 80, Exit 

#261 (Beowawe exit) on State Route 306, in Lander and Eureka Counties, Nevada. The facility 

operates both open-pit and underground mines. Gold recovery operations include: crushing, 

milling, heap and tank leaching, carbon adsorption, stripping and regeneration, electrowinning, 

and smelting. The leach solutions used in the gold recovery processes contain cyanide. These 

solutions have the potential for low levels of HCN formation and emission to the atmosphere. To 

assess the ambient concentrations of HCN emissions, 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 Meteorological 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, the 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 neighboring 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 2 6

8

5

8 9 12

13

7 8

11

30

31

19

18

25

20

27

32

18

28 26

24

33

32

34

15

21 22

16

35

29

17

13

36

17

23

14

17 16 15 14

10

20

29

17

8 9

6

11 12

7

10

19

18

30

7

31

21 22 23 24

18

20 19 20

9

16

19 21

T28N:R47E

T27N:R47E

T28N:R48E

T27N:R48E

525000

525000

530000

530000

535000

535000

44500004450000

44550004455000

44600004460000

Datum: NAD83 UTM Zone 11N

Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Compliance\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

SITE_ID EAST NORTH Looking Northeast

AQM-001 532667 4457396

2
!(

!(

!(

!(

\ [ HCN Monitoring Site

Barrick Owned Ranch Houses

80

278

305

306

766

LANDER CO.

EUREKA CO.

ELKO CO.

HUMBOLDT

Met Tower

(Pipeline)

Carlin

Beowawe

Battle Mountain

Crescent Valley

500000

500000

520000

520000

540000

540000

560000

560000

580000

580000

44400004440000

44600004460000

44800004480000

45000004500000

45200004520000

Datum: NAD83 UTM Zone 11N

Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Compliance\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

3
AREA 28

AREA 30

Tailings Storage

Impoundment

Mill Area

522000

522000

524000

524000

526000

526000

528000

528000

44520004452000

44540004454000

44560004456000

44580004458000

Datum: NAD83 UTM Zone 11N

Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Compliance\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

4
CIL Tanks

CIC Tanks

Preg / Barren Tank

E. Cell Stack

W. Cell Stack

523800

523800

524000

524000

524200

524200

44568004456800

44570004457000

Datum: NAD83 UTM Zone 11N

Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Compliance\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

5
Draft_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 speed and wind direction are collected at the 

Pipeline meteorological station. Ambient temperature, relative humidity, and barometric 

pressure as well as flow rate through the sorbent tubes are collected at the HCN monitor. 

Ambient temperature, relative humidity, and barometric 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 meteorological 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 averages are transmitted to Air Sciences for quality 

assurance checks and population into the database. 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 parameters are presented in Table 2. 

The meteorological data recovery rate was 100 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 Applications). 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, temperature, relative humidity, and barometric 

pressure data collected at the Pipeline meteorological 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 direction and speed. The data period contains 25 

days (600 hours) of complete wind information. 

Figure 5 shows the distribution of hourly averaged 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 percent 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 speeds were greater than 5 m/s. 

Table 4 shows a frequency distribution of hourly averaged winds by direction 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 F 

indicate 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 speeds. 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 winds (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 Averaged 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 Class
Draft_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 = 2,072
Draft_Cortez Hcn Monitoring Report_R2.Docx 11 

2.2 Temperature, Relative Humidity, and Barometric Pressure 

The temperature mean and extremes for the sampling 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 sampling 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., for two consecutive hours on December 23, 2009, 

beginning at 11:00 p.m., and again for thirteen 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 10 624 
Draft_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 Humidity, and Barometric Pressure 

The temperature mean and extremes for the sampling 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 sampling 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 December 24, 2009, beginning at 6:00 a.m. The 

minimum hourly averaged barometric pressure for the period was 646 mmHg and occurred for 

seven consecutive hours on December 6, 2009, beginning 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 28 646 
Draft_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 detection 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 weeks of monitoring, an analysis 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 sources towards the monitor only four percent of 

the time. On the second lowest concentration day, the winds blew from the potential HCN 

sources towards the monitor 25 percent of the time, 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 direction (the direction from which the wind is 

blowing) and wind speed for the lowest and highest 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

1

Standard Concentration (ppb)

Percentof Winds (%)

Run Day

Standard Concentration (ppb) Percentof Winds towards Monitor
Draft_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 Data 
Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 

11/30/2009 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 

12/1/2009 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 12/2/2009 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 12/3/2009 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 12/4/2009 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 12/5/2009 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 12/6/2009 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 12/7/2009 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 12/8/2009 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 12/9/2009 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 

12/10/2009 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 12/11/2009 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 12/12/2009 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 12/13/2009 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 12/14/2009 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 12/15/2009 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 12/16/2009 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 12/17/2009 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 12/18/2009 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 12/19/2009 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 12/20/2009 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 12/21/2009 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 12/22/2009 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 12/23/2009 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 12/24/2009 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 

Avg 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 

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 

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 

SAROAD for Barrick, Cortez  ‐ Pipeline

Channel: WS_ms

Month: 11/30/09 ‐ 12/24/09

Hour of da

y
Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 

11/30/2009 296 168 257 264 326 174 162 10 83 86 112 92 47 132 75 72 334 280 270 269 277 

12/1/2009 270 323 64 163 60 341 339 69 147 177 56 114 53 47 65 64 4 310 275 257 299 12/2/2009 171 222 226 306 289 282 119 207 114 75 84 65 55 51 63 59 343 277 271 257 342 12/3/2009 313 167 224 264 290 274 193 133 109 92 90 119 89 67 83 72 341 278 271 270 271 12/4/2009 61 50 265 293 21 342 346 22 30 54 70 52 41 69 252 194 205 200 205 238 231 12/5/2009 230 219 254 275 65 42 22 36 57 32 27 14 4 345 349 23 4 13 333 135 258 12/6/2009 268 226 252 330 314 310 329 135 0 70 51 23 278 325 72 330 347 23 262 151 225 12/7/2009 233 226 284 9 46 27 58 63 56 45 50 47 34 31 36 29 23 67 93 77 86 12/8/2009 272 269 297 314 323 295 260 261 47 10 152 121 66 17 29 10 251 262 248 126 227 12/9/2009 309 282 219 0 124 318 343 308 35 43 117 45 50 66 69 9 272 249 157 294 170 

12/10/2009 92 333 42 209 215 169 60 98 332 91 133 133 100 93 115 289 218 163 229 333 285 12/11/2009 27 326 285 56 336 17 152 38 91 80 70 40 46 34 134 111 191 155 126 84 65 12/12/2009 346 168 351 213 216 230 210 185 188 203 155 201 351 251 81 150 184 247 249 291 326 12/13/2009 0 283 201 227 240 167 183 186 204 234 221 217 225 228 233 230 237 218 199 231 246 12/14/2009 242 240 233 255 249 268 209 284 268 98 214 201 227 215 357 302 274 274 255 283 2 12/15/2009 228 227 292 239 240 341 345 12 268 243 235 258 234 274 221 231 216 224 217 213 246 12/16/2009 241 280 231 326 358 278 227 255 299 201 212 17 61 5 328 182 252 238 317 258 316 12/17/2009 14 280 152 49 151 341 25 297 183 59 11 50 36 43 39 316 233 234 254 259 171 12/18/2009 294 137 312 340 291 234 354 307 197 85 202 42 38 33 87 338 290 269 263 263 248 12/19/2009 341 55 220 12 4 273 272 68 64 28 103 69 5 97 83 174 218 281 259 314 331 12/20/2009 287 149 354 32 31 73 114 8 148 104 88 71 78 33 77 167 29 302 231 190 345 12/21/2009 223 348 1 342 336 313 347 191 98 48 66 22 17 29 42 276 322 21 246 303 181 12/22/2009 229 172 257 229 241 273 167 21 41 51 48 41 46 52 37 23 6 314 257 210 221 12/23/2009 216 258 256 232 247 246 327 278 29 46 55 28 29 31 357 29 333 268 264 263 271 12/24/2009 218 356 331 337 292 120 159 52 26 14 35 28 43 28 11 351 303 264 178 217 237 

Avg 217 231 234 213 212 230 213 141 125 91 106 84 90 104 132 161 217 217 237 231 235 

Max 346 356 354 342 358 342 354 308 332 243 235 258 351 345 357 351 347 314 333 333 345 

Min 0 50 1 0 4 17 22 8 0 10 11 14 4 5 11 9 4 13 93 77 2 

SAROAD for Barrick, Cortez  ‐ Pipeline

Channel: WD_deg

Month: 11/30/09 ‐ 12/24/09

Hour of da

y
Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 

11/30/2009 ‐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 ‐

12/1/2009 ‐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 ‐

12/2/2009 ‐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 ‐

12/3/2009 ‐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 ‐

12/4/2009 ‐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

12/5/2009 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 ‐

12/6/2009 ‐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 ‐

12/7/2009 ‐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 ‐

12/8/2009 ‐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 ‐1

12/9/2009 ‐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 ‐1

12/10/2009 ‐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 ‐1

12/11/2009 ‐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 ‐

12/12/2009 ‐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

12/13/2009 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 1.6 112/14/2009 ‐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 ‐

12/15/2009 ‐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

12/16/2009 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 ‐

12/17/2009 ‐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

12/18/2009 ‐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 ‐

12/19/2009 ‐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 ‐

12/20/2009 ‐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 ‐

12/21/2009 ‐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 ‐

12/22/2009 ‐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 ‐

12/23/2009 ‐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 ‐1

12/24/2009 ‐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 ‐1

Avg ‐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 ‐

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

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 ‐1

SAROAD for Barrick, Cortez  ‐ Pipeline

Channel: Temp_C

Month: 11/30/09 ‐ 12/24/09

Hour of da

y
Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 

11/30/2009 64 66 63 63 71 73 74 68 53 50 43 37 30 31 32 34 42 45 47 48 50 

12/1/2009 64 69 71 74 74 77 79 75 59 42 38 36 33 33 32 33 40 45 49 50 54 12/2/2009 69 72 71 71 78 77 81 77 63 56 56 55 54 52 51 52 59 63 63 68 74 12/3/2009 73 78 78 75 78 84 84 81 68 64 55 45 37 34 32 31 39 45 45 47 44 12/4/2009 60 62 61 60 62 64 62 55 48 41 32 25 21 21 18 13 10 12 14 13 14 12/5/2009 21 21 26 32 48 53 55 52 49 41 37 31 30 29 34 46 44 44 48 52 56 12/6/2009 58 56 60 68 70 71 71 70 59 54 47 41 46 43 39 55 74 78 70 85 73 12/7/2009 71 77 77 83 86 86 87 87 86 85 85 85 85 85 86 87 88 86 87 87 87 12/8/2009 79 74 76 77 80 82 82 81 75 69 61 55 64 69 73 75 79 79 80 81 82 12/9/2009 80 79 78 79 77 79 75 77 76 76 79 79 79 77 71 73 78 77 79 79 81 

12/10/2009 81 80 80 79 79 79 78 78 77 77 78 78 71 68 71 71 78 81 80 83 83 12/11/2009 81 82 82 82 82 82 82 82 81 76 67 58 58 55 58 80 86 87 87 88 87 12/12/2009 88 89 88 86 88 89 85 82 78 76 67 59 64 70 69 68 70 84 83 88 90 12/13/2009 92 89 85 77 72 75 76 75 75 75 73 71 72 68 67 65 69 73 71 74 75 12/14/2009 78 78 79 79 79 82 83 85 83 85 82 77 75 72 77 75 86 84 84 85 86 12/15/2009 74 76 75 62 62 79 81 78 65 50 50 50 49 47 51 57 60 65 62 62 59 12/16/2009 64 72 66 75 76 69 62 71 68 59 60 66 63 65 55 57 74 72 77 80 84 12/17/2009 88 89 89 90 90 89 90 90 89 82 79 75 73 68 65 71 79 81 82 79 84 12/18/2009 87 88 89 90 89 89 89 89 78 71 66 70 72 71 66 69 79 82 83 82 83 12/19/2009 90 90 90 89 89 89 88 88 88 88 89 88 87 75 77 80 86 88 84 87 88 12/20/2009 90 89 88 88 87 87 87 87 87 88 88 89 89 90 90 90 90 90 88 79 88 12/21/2009 89 89 89 90 89 89 90 90 88 85 80 79 75 75 75 77 80 80 74 73 80 12/22/2009 89 91 92 87 85 86 89 78 74 82 85 80 79 79 79 76 78 77 81 77 75 12/23/2009 74 76 75 76 77 74 81 82 71 70 68 71 70 67 64 69 76 80 80 80 84 12/24/2009 85 85 85 84 83 83 83 83 82 81 82 79 75 70 66 69 78 83 83 83 78 

Avg 76 77 76 77 78 80 80 78 73 69 66 63 62 60 60 63 69 71 71 72 74 

Max 92 91 92 90 90 89 90 90 89 88 89 89 89 90 90 90 90 90 88 88 90 

Min 21 21 26 32 48 53 55 52 48 41 32 25 21 21 18 13 10 12 14 13 14 

SAROAD for Barrick, Cortez  ‐ Pipeline

Channel: RH_percent

Month: 11/30/09 ‐ 12/24/09

Hour of da

y
Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 

11/30/2009 643 643 643 643 643 643 643 643 643 643 642 641 641 640 639 639 639 639 639 639 639 

12/1/2009 639 638 639 638 638 638 638 638 638 638 638 637 637 636 636 636 636 636 636 636 637 12/2/2009 637 637 637 637 637 638 638 638 638 638 638 638 637 637 637 637 637 637 637 637 638 12/3/2009 639 639 639 639 640 640 641 641 642 642 642 642 641 641 641 641 641 642 642 642 642 12/4/2009 642 642 642 642 641 641 641 641 641 640 640 639 638 637 637 636 635 635 635 635 634 12/5/2009 632 632 632 632 633 634 634 634 634 634 634 634 633 633 633 633 633 633 633 633 633 12/6/2009 632 632 631 631 631 630 630 630 630 630 629 628 627 627 626 626 626 626 627 627 627 12/7/2009 628 627 627 627 627 627 627 627 627 626 626 625 624 624 624 624 624 624 624 625 625 12/8/2009 627 628 628 629 630 631 632 632 633 634 634 633 633 633 633 634 634 634 635 635 635 12/9/2009 637 637 637 637 637 637 637 637 638 638 637 637 636 636 636 637 637 637 637 637 637 

12/10/2009 637 637 637 637 637 637 637 637 638 638 638 637 637 636 636 636 636 636 636 636 636 12/11/2009 636 636 636 636 635 635 635 635 635 635 635 634 634 634 634 634 634 634 634 634 634 12/12/2009 633 633 633 633 633 632 632 632 633 633 633 632 631 631 630 630 630 629 628 628 627 12/13/2009 626 627 627 627 627 628 628 629 630 630 631 631 632 632 632 633 633 634 634 634 635 12/14/2009 636 636 637 637 637 637 638 638 639 640 640 639 639 639 639 639 639 639 640 640 640 12/15/2009 640 640 640 640 640 640 640 640 640 641 641 641 640 640 640 640 640 640 641 641 641 12/16/2009 641 641 641 641 641 641 641 641 642 642 642 642 642 642 642 642 642 642 642 642 642 12/17/2009 643 643 643 643 643 643 643 643 644 644 643 643 643 642 643 643 643 643 643 643 643 12/18/2009 643 642 642 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 643 12/19/2009 643 643 643 643 643 643 643 643 643 643 643 642 642 642 641 641 641 641 641 641 641 12/20/2009 641 641 640 640 640 640 640 640 640 640 639 639 638 638 638 638 638 638 638 637 638 12/21/2009 637 638 637 637 637 637 637 636 636 636 636 635 634 633 633 632 632 631 631 631 630 12/22/2009 630 630 629 629 629 628 629 629 630 631 631 631 631 632 632 633 634 635 635 636 636 12/23/2009 638 639 640 640 640 641 641 641 642 643 642 642 642 642 642 642 642 643 643 643 643 12/24/2009 644 644 644 644 644 644 644 644 644 644 644 644 644 643 643 643 643 643 643 643 642 

Avg 637 637 637 637 637 637 637 637 638 638 638 637 637 637 636 636 636 637 637 637 637 

Max 644 644 644 644 644 644 644 644 644 644 644 644 644 643 643 643 643 643 643 643 643 

Min 626 627 627 627 627 627 627 627 627 626 626 625 624 624 624 624 624 624 624 625 625 

SAROAD for Barrick, Cortez  ‐ Pipeline

Channel: BP_mmHg

Month: 11/30/09 ‐ 12/24/09

Hour of da

y
Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 

11/30/2009 ‐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 ‐

12/1/200912/2/200912/3/2009 ‐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 ‐

12/4/200912/5/200912/6/2009 ‐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 ‐

12/7/200912/8/200912/9/2009 ‐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 ‐

12/10/200912/11/200912/12/2009 ‐14.1 ‐11.8 ‐11.1 ‐8.7 ‐3.1 ‐1.9 ‐1.7 ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ 0.3 ‐0.6 ‐

12/13/200912/14/200912/15/2009 ‐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 

12/16/200912/17/200912/18/2009 ‐‐ ‐‐ ‐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 ‐

12/19/200912/20/200912/21/2009 ‐13.8 ‐14.3 ‐14.4 ‐13.7 ‐13.2 ‐13.1 ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ 

12/22/200912/23/200912/24/2009 ‐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 ‐

Avg ‐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 ‐

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 

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 ‐

‐‐ Indicate invalid data

SAROAD for Barrick, Cortez  ‐ HCN

Channel: T_AMB_C

Month: 11/30/09 ‐ 12/24/09

Hour of da

y

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day
Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 

11/30/2009 76 77 76 79 80 81 83 74 58 48 41 35 34 33 32 34 44 57 64 67 69 

12/1/200912/2/200912/3/2009 88 83 87 87 85 84 83 85 71 59 56 42 32 30 28 32 38 57 57 61 62 12/4/200912/5/200912/6/2009 75 74 77 79 78 78 79 78 65 59 51 44 41 40 43 52 74 80 80 92 86 12/7/200912/8/200912/9/2009 72 72 71 70 71 70 70 71 77 79 83 83 76 71 70 74 81 81 80 76 77 

12/10/200912/11/200912/12/2009 92 94 93 95 91 86 84 ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ 91 97 

12/13/200912/14/200912/15/2009 91 91 92 94 94 94 93 93 88 64 60 55 56 51 52 51 58 64 68 69 73 12/16/200912/17/200912/18/2009 ‐‐ ‐‐ 95 96 95 95 95 94 85 74 63 60 67 68 65 67 78 91 95 96 95 12/19/200912/20/200912/21/2009 92 91 93 92 92 92 ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ 

12/22/200912/23/200912/24/2009 82 82 82 81 80 80 83 81 82 72 70 65 63 62 62 67 74 85 86 84 84 

Avg 84 83 85 86 85 85 84 82 75 65 61 55 53 51 50 54 64 73 76 79 80 

Max 92 94 95 96 95 95 95 94 88 79 83 83 76 71 70 74 81 91 95 96 97 

Min 72 72 71 70 71 70 70 71 58 48 41 35 32 30 28 32 38 57 57 61 62 

‐‐ Indicate invalid data

SAROAD for Barrick, Cortez  ‐ HCN

Channel: RH_percent

Month: 11/30/09 ‐ 12/24/09

Hour of da

y

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day
Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 

11/30/2009 659 659 659 659 658 658 659 659 659 659 658 657 657 656 656 656 656 656 656 656 656 

12/1/200912/2/200912/3/2009 655 656 656 656 656 657 657 657 658 658 658 658 657 657 657 657 657 658 658 658 658 12/4/200912/5/200912/6/2009 650 650 650 650 650 649 649 649 649 648 648 647 646 646 646 646 646 646 646 647 646 12/7/200912/8/200912/9/2009 654 654 654 654 654 654 655 655 655 655 654 654 654 654 654 654 654 654 654 654 654 

12/10/200912/11/200912/12/2009 651 651 651 651 651 650 650 ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ 647 646 

12/13/200912/14/200912/15/2009 656 656 656 656 656 656 656 656 657 657 657 657 656 656 656 656 656 657 657 657 657 12/16/200912/17/200912/18/2009 ‐‐ ‐‐ 658 658 658 659 659 659 659 659 659 658 658 658 658 658 658 658 658 658 659 12/19/200912/20/200912/21/2009 654 655 654 654 654 654 ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ 12/22/200912/23/200912/24/2009 659 659 660 659 659 660 660 660 660 660 660 659 659 659 659 659 659 659 659 659 658 

Avg 655 655 655 655 655 655 656 656 656 656 656 656 655 655 655 655 655 655 655 654 654 

Max 659 659 660 659 659 660 660 660 660 660 660 659 659 659 659 659 659 659 659 659 659 

Min 650 650 650 650 650 649 649 649 649 648 648 647 646 646 646 646 646 646 646 647 646 

‐‐ Indicate invalid data

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

Non‐Run‐Day

SAROAD for Barrick, Cortez  ‐ HCN

Channel: BP_mmHg

Month: 11/30/09 ‐ 12/24/09

Hour of da

y

Non‐Run‐Day

Non‐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

9353014001 12/18/2009

Sample ID:

Lab ID:

Media: Collected:

Received:

59561209-1 SKC 226-28, Soda Lime-200/600

Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

Hydrogen Cyanide 0.76 NA NA 0.21

12/12/2009

9353014002 12/18/2009

Sample ID:

Lab ID:

Media: Collected:

Received:

59561212-2 SKC 226-28, Soda Lime-200/600

Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

Hydrogen Cyanide 0.79 NA NA 0.21

12/15/2009

9353014003 12/18/2009

Sample ID:

Lab ID:

Media: Collected:

Received:

59561215-3 SKC 226-28, Soda Lime-200/600

Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

Hydrogen Cyanide 0.91 NA NA 0.21

12/18/2009

9353014004

Sample ID:

Lab ID:

59561217-Blank Media: SKC 226-28, Soda Lime-200/600 Received:

Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

Hydrogen Cyanide <0.21 NA NA 0.21

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 Laboratories, 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 unless otherwise noted.

Samples have not been blank corrected unless otherwise noted.

This test report shall not be reproduced, except in full, without written approval of ALS Laboratory Group.

ALS Laboratory Group is accredited by AIHA for specific fields of testing as documented in its current scope of accreditation

(ID#101574) which is available on request by contacting your project manager or view on the internet at http://www.aiha.org. The

quality systems implemented in the laboratory apply to all methods performed by ALS Laboratory Group regardless of this current

scope of accreditation which does not include performance based methods, modified methods, and methods applied to matrices

not listed in the methods.

ALS DataChem provides professional analytical services for all samples submitted. ALS Laboratory Group is not in a position to

interpret the data and assumes no responsibility for the quality of the samples submitted.

All quality control samples processed with the samples in this report yielded acceptable results unless otherwise noted.

General Lab Comments

LOD = Limit of Detection = MDL = Method Detection Limit, A statistical estimate of method/media/instrument sensitivity.

LOQ = Limit of Quantitation = RL = Reporting Limit, A verified value of method/media/instrument sensitivity.

ND = Not Detected, Testing result not detected above the LOD or LOQ.

** No result could be reported, see sample comments for details.

< This testing result is less than the numerical value.

( ) This testing result is between the LOD and LOQ and has higher analytical uncertainty than values at 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

9362011001 12/28/2009

Sample ID:

Lab ID:

Media: Collected:

Received:

595612182009-1 SKC 226-28, Soda Lime-200/600

Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

Hydrogen Cyanide 1.9 NA NA 0.21

12/18/2009

9362011002 12/28/2009

Sample ID:

Lab ID:

Media: Collected:

Received:

595612212009-2 SKC 226-28, Soda Lime-200/600

Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

Hydrogen Cyanide 2.5 NA NA 0.21

12/18/2009

9362011003 12/28/2009

Sample ID:

Lab ID:

Media: Collected:

Received:

595612242009-3 SKC 226-28, Soda Lime-200/600

Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

Hydrogen Cyanide <0.21 NA NA 0.21

12/18/2009

9362011004 12/28/2009

Sample ID:

Lab ID:

Media: Collected:

Received:

Blank SKC 226-28, Soda Lime-200/600

Sampling Location: Cortez

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 12/28/2009

RL (ug/sample)

Hydrogen Cyanide <0.21 NA NA 0.21

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 Laboratories, 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 unless otherwise noted.

Samples have not been blank corrected unless otherwise noted.

This test report shall not be reproduced, except in full, without written approval of ALS Laboratory Group.

ALS Laboratory Group is accredited by AIHA for specific fields of testing as documented in its current scope of accreditation

(ID#101574) which is available on request by contacting your project manager or view on the internet at http://www.aiha.org. The

quality systems implemented in the laboratory apply to all methods performed by ALS Laboratory Group regardless of this current

scope of accreditation which does not include performance based methods, modified methods, and methods applied to matrices

not listed in the methods.

ALS DataChem provides professional analytical services for all samples submitted. ALS Laboratory Group is not in a position to

interpret the data and assumes no responsibility for the quality of the samples submitted.

All quality control samples processed with the samples in this report yielded acceptable results unless otherwise noted.

General Lab Comments

LOD = Limit of Detection = MDL = Method Detection Limit, A statistical estimate of method/media/instrument sensitivity.

LOQ = Limit of Quantitation = RL = Reporting Limit, A verified value of method/media/instrument sensitivity.

ND = Not Detected, Testing result not detected above the LOD or LOQ.

** No result could be reported, see sample comments for details.

< This testing result is less than the numerical value.

( ) This testing result is between the LOD and LOQ and has higher analytical uncertainty than values at 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 

BARRICK CORTEZ, INC. 

PROJECT 59-52-10 

OCTOBER 2009 
Cortez 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 Plan 

 
Cortez 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 State 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 regeneration, 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 sampling 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 Appendix 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 sources 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 also 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 boundary, 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 mph

Wind Frequency ‐ Hourly Met.Data

01/01/08 ‐ 12/31/08

Calmhours = 89  Missing hours = 121

Numberof non‐calm/missinghours = 8,574
Cortez 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 mph

Wind Frequency ‐ Hourly Met.Data Calmhours = 44  Missing hours = 0 Numberof 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 mph

Wind Frequency ‐ Hourly Met.Data

Calmhours = 1  Missing hours = 0

Numberof 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 mph

Wind Frequency ‐ Hourly Met.Data

Calmhours = 0  Missing hours = 0 Numberof 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 mph

Wind Frequency ‐ Hourly Met. Data

Calmhours = 44  Missinghours = 121

Numberof non‐calm/missing hours = 2,043
Cortez Site-Specific Hcn Monitoring Plan_V2.Docx 4 

SECTION 3 

PROPOSED HCN MONITORING SITE 

3.1 Operations Boundary and 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 are 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 extract 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. The 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 to 
Cortez 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 from 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 public 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, however, 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 provide 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 2 6

8

7

8

5

8 9

8 9

1 6 5

3 2

5

12

4

11

11

30

31

19

17

20

32

25

20

29

27

32

18

28 26

24

33 34

15

10

21 22

16

35

29

17

13

12

36

23

14

10

7

6

18

19

6

30

31

7

9

4

17 16 15 14 13 18

9

17

33

4

18 16

T28N:R47E T28N:R48E

T27N:R47E T27N:R48E

525000

525000

530000

530000

535000

535000

44550004455000

44600004460000

Datum: NAD83 UTM Zone 11N

Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Compliance\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

766

LANDER CO.

EUREKA CO.

ELKO CO.

HUMBOLDT

Met Tower

(Pipeline)

Carlin

Beowawe

Battle Mountain

Crescent Valley

500000

500000

520000

520000

540000

540000

560000

560000

580000

580000

44400004440000

44600004460000

44800004480000

45000004500000

45200004520000

Datum: NAD83 UTM Zone 11N

Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Compliance\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

528000

44520004452000

44540004454000

44560004456000

44580004458000

Datum: NAD83 UTM Zone 11N

Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Compliance\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

524200

44568004456800

44570004457000

Datum: NAD83 UTM Zone 11N

Projection: Transverse_Mercator P:\Environmental\GIS\Projects\District\Air Quality Compliance\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 

NEVADA MINING ASSOCIATION

PROJECT 59-43-70 

OCTOBER 2009 
Hcn 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, INSPECTION, 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 ................................................................................................. 21 
Hcn 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 6010
Hcn 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 developed 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 Systems 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 2 
Hcn 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 under 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 notes and anomalies, and 

• Corrective actions taken (if any). 

After the first four weeks of sampling, preliminary 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 and federal guidelines are strictly defined for 

meteorology but not for HCN. The equipment selection 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 plan submitted by each mine will address the 

proposed location of the meteorological monitoring 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 Campbell Scientific 019ALU 

Pyranometer mounting arm Campbell Scientific 015ARM 

Data logger CR3000 Campbell Scientific CR23X or CR10X 

Power supply with battery Campbell Scientific PS12LA 

Solar panel Campbell Scientific MSX10R 

Wind sensor R.M. Young 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 Transducer 
Hcn 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 instrumentation 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 exceed 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 architecture. 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 months of data and will 

provide a backup of the data and the CR3000 program 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 sensor of the Model 05305 is a helicoid-shaped, fourblade propeller. Rotation of the 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 platinum 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 radiation. 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 HUMICAPTM 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 the relative humidity sensor is 15 seconds. 

5.1.9 Barometric Pressure 

Barometric pressure is measured every 15 minutes using a Vaisala PT101B sensor. The sensor is 

mounted inside the data logger enclosure. Barometric pressure is measured by the data logger 

using Vaisala’s Barocap silicon capacitive pressure 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. The 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 passed through the sorbent tubes. Data collection 

is in twenty-four hour increments. Upon complete exposure of a sorbent tube, it is sealed and 
Hcn 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 consists 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 designed 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 volume of the sorbent tube and necessary to reach 

the required limits of detection. 

A data logger turns the pump on and off and controls 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 also 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, showing 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 VALVE
Hcn 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 VALVE
Hcn 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 and 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 analyzed using spectroscopy. One in every five 

sorbent tubes will be a field blank. 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 VALVE
Hcn Sampling Plan_V7.Docx 12 

The detection limit for this HCN sampling method is reported to be approximately 0.2 ppb1, 

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 communications 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 day 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 gold 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 System Failure Response 

The primary mechanism for ensuring normal system operation will be comprised of on-site 

checks conducted after the tubes have been sampled 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 Requirements 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 Method 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 cyanide 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 provided 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 out 
Hcn 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 accomplished 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 Campbell 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 Check Forms and compare them to the 15-minute data 

averages to ensure proper system operation and data transfer. 

7.2 Instrument Calibration and Frequency 

The following section outlines the preventive maintenance/recalibration of the equipment used 

to test the performance of the on-site systems. 

7.2.1 Calibration Equipment 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 Records and Traceability 

Calibration Forms are completed and maintained by project personnel. All Calibration Forms 

indicate the sensor calibrated, its serial number, 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 data 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 assurance 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 deviation 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 placed 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

S i Sin

N

V

1

1 θ

= ∑

N

C Cos i 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 σ θ1 = ArcSin ε 1+ 0.1547ε

 where, [ ] (() () ) 2

1

2 2 1 = − VS + VC 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 invalid, 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/m3 @ 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 (Sr): 0.041 @ 10 to 50 mg per sample [1]

ACCURACY

RANGE STUDIED: 2 to 15 mg/m3 [1]

(3-L samples)

BIAS: Not significant

OVERALL PRECISION (Sˆ

rT): 0.076 [1]

ACCURACY: ± 15.0%

APPLICABILITY: The working range is 0.3 to 235 ppm (3 to 260 mg/m3) 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 and

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

AgNO3 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 (Wf) and back (Wb)

sorbent sections and in the average media blank front (Bf) and back (Bb) sorbent sections. If

Wb > Wf/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/m3 for a 3-L air sample. Twenty-two samples collected at 0.2 L/min for 15 minutes

indicated overall precision Sˆ

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/m3. 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

(AgNO3) solution. The end point is the first formation of a white precipitate, Ag[Ag(CN) 2]. Calculate the

cyanide concentration with the following equation:

Mc = 52.04 Va (Ma/Vc)

Where Mc = cyanide concentration (mg/mL)

Va = volume (mL) of standard silver nitrate solution

Ma = concentration (moles/L) of standard silver nitrate solution

Vc = volume (mL) of calibration stock solution titrated

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