Meteorological and 

Hydrogen Cyanide 

(HCN) Perimeter 

Monitoring 

Preliminary Report 

MARIGOLD MINING COMPANY

PROJECT 235-3-4 

January 2010 
Marigold Preliminary Hcn Monitoring Report.Docx ii 

CONTENTS Page

1.0 INTRODUCTION ......................................................................................................................................................... 1 

1.1 HCN Monitor and Meteorological Station Locations ............................................................................................... 1

1.2 HCN Monitoring System Description ...................................................................................................................... 5

1.3 Data Recovery ....................................................................................................................................................... 6

1.4 Quality Control ........................................................................................................................................................ 6

2.0 METEOROLOGY AT THE METEOROLOGICAL STATION ..................................................................................... 7

2.1 Winds ..................................................................................................................................................................... 7

2.2 Temperature and Barometric Pressure ............................................................................................................... 10

3.0 HCN STATION ......................................................................................................................................................... 11

3.1 Winds ................................................................................................................................................................... 11

3.2 Temperature, Relative Humidity, and Barometric Pressure ............................................................................... 11

3.3 HCN Concentration .............................................................................................................................................. 12

4.0 DATA ANALYSIS ..................................................................................................................................................... 13

Tables 

Table 1: Sensor Locations ............................................................................................................................................... 5 

Table 2: Data Recovery ................................................................................................................................................... 6 

Table 3: Frequency of Hourly Averaged Winds by Direction and Speed ......................................................................... 8 

Table 4: Frequency of Hourly Averaged Winds by Direction and Stability ....................................................................... 8 

Table 5: Temperature and Barometric Pressure ............................................................................................................ 10 

Table 6: Temperature and Relative Humidity ................................................................................................................. 11 

Table 7: HCN Concentration .......................................................................................................................................... 12 

Table 8: Measured HCN Concentration Analysis ........................................................................................................... 13 

Figures 

Figure 1: HCN Monitoring Site ......................................................................................................................................... 2 

Figure 2: Large Scale Area Map ...................................................................................................................................... 3 

Figure 3: Refinery and Ponds .......................................................................................................................................... 4 

Figure 4: Wind Frequency Distribution ............................................................................................................................. 9 

Figure 5: Measured HCN Concentration Analysis ......................................................................................................... 14 

Figure 6: Wind frequency for December 30, 2009 (Lowest Concentration Day) ............................................................ 15 

Figure 7: Wind frequency for December 18, 2009 (Highest Concentration Day) ........................................................... 15 

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 
Marigold Preliminary Hcn Monitoring Report.Docx 1 

SECTION 1 

INTRODUCTION 

This report summarizes the meteorological and hydrogen cyanide (HCN) data collected at the 

Marigold Mining Company (Marigold) meteorological station and HCN monitor through January 11, 

2010. The HCN monitor station became operational on December 17, 2009, at 12:00 p.m. and the first 

24-hour HCN sample was taken on December 18, 2009. The HCN monitoring equipment and 

sampling procedures followed Marigold’s Site-Specific Hydrogen Cyanide (HCN) Perimeter Monitoring 

Plan (Site Specific Plan), approved by EPA on November 10, 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. 

Marigold operates a gold mining facility located approximately four miles south of Interstate 80 at 

the Valmy Interchange (Exit 216), in Humboldt County, Nevada. The Marigold facility consists of 

open-pit mining and gold recovery processes including heap leaching, carbon adsorption, stripping 

and regeneration, electrowinning, retorting, and refining. 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, Marigold installed and continues to operate an HCN monitor downwind of the potential HCN 

sources, at the boundary of the project operations at the Marigold mine. 

1.1 HCN Monitor and Meteorological Station Locations 

Aerial photos and shaded relief maps are provided in Figures 1 through 3. Figure 1 provides an 

aerial photo of the mine site, the project boundary, the potential HCN sources, and the HCN monitor 

location. Figure 2 provides a shaded relief map of the area surrounding the Marigold mine and 

shows the location of the HCN monitor. The meteorological station is co-located with the HCN 

monitor at 488,951 meters east, 4,511,675 meters north, UTM Zone 11N, NAD83, elevation 4,669 feet. 

Figures 1 and 3 highlight the potential sources of HCN emissions at Marigold. These sources include 

a leach pad, pregnant and barren ponds, tanks containing cyanide solution, and a single stack for the 

electrowinning cells and pregnant and barren tanks at the refinery. A closer view of the HCN 

sources at the refinery and pond area is shown in Figure 3. 
Marigold Preliminary Hcn Monitoring Report.Docx 2
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Marigold Preliminary Hcn Monitoring Report.Docx 5 

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 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 timeaveraged into 15-minute values. Wind speed and wind direction are collected at the 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 and barometric 

pressure are also collected at the co-located 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 meteorological station. 

The 15-minute averaged data from the 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 meteorological station and the 

HCN monitor are used as input to the Air Sciences’ database for the calculation of one-hour averages. 
Marigold Preliminary Hcn Monitoring Report.Docx 6 

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 meteorological station 

and at the HCN monitor, with the exception of barometric pressure from the HCN monitor. The 

barometric pressure sensor at the HCN monitor was faulty and was replaced on January 15, 2010. 

Barometric pressure data from the co-located meteorological station was used in its stead. The data 

recovery rates at the meteorological and HCN station are above the recommended rate of 90 percent 

for all meteorological parameters, except, as noted above, for the barometric pressure at the HCN 

monitor station itself. 

The data recovery rate for the flow rate to the sorbent tubes was 100 percent; the data recovery rate 

for the HCN concentration from the sorbent tubes was also 100 percent. Both parameters are above 

the recommended recovery rate of 75 percent. 

Table 2: Data Recovery 

December 18, 2009 - January 11, 2010 

(percent) 

 Recorded Recommended 

Parameter Observations Recovery Rate Recovery Rate 

Meteorological Station 

 Wind speed 600 100.0 90 

 Wind direction 600 100.0 90 

 Ambient temperature 600 100.0 90 

 Barometric pressure 600 100.0 90 

HCN Station 

 Ambient temperature 216 100.0 90 

 Relative humidity 216 100.0 90 

 Barometric pressure * 0.0 90 

 Flow 216 100.0 75 

 HCN concentration 9 100.0 75 

* The barometric pressure data from the HCN monitor was invalid due to a faulty sensor. Barometric pressure data from the 

co-located meteorological station was used in its stead. 

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. 

 
Marigold Preliminary Hcn Monitoring Report.Docx 7 

SECTION 2 

METEOROLOGY AT THE METEOROLOGICAL STATION 

The instantaneous wind speed, wind direction, temperature, and barometric pressure data collected 

at the 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 4 shows the distribution of hourly averaged winds by direction and speed for the sampling 

period. The mean wind speed for the period was 1.8 m/s (4.0 mph). The winds were fairly evenly 

distributed for the period and ranged from moderate to brisk. A breakdown of the wind speed 

profile for this period yields the following: There were 2.0 percent calm wind speeds (<0.447 m/s), 

53.7 percent of the winds were between 0.5 m/s (1.1 mph) and 1.5 m/s (3.4 mph), 41.4 percent of the 

winds were between 1.5 m/s and 5 m/s (11.2 mph), and 3.0 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 low-dispersionpotential 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 18.7 percent of the total winds and 

were predominately from the east to the east-southeast. The lower-speed nighttime winds (classes E 

and F) constituted 56.8 percent of the total winds and were predominately from the southeast to the 

south-southeast with a secondary peak from the west-southwest to the west-northwest. The higherspeed winds (class D) comprised 24.5 percent of the total winds and were predominately from the 

west-southwest to the northwest. 

 
Marigold Preliminary Hcn Monitoring Report.Docx 8 

Direction A B C D E F All

N 0.0 0.7 0.7 1.2 0.3 0.7 3.5

NNE 0.0 0.5 0.5 0.7 0.3 0.8 2.8

NE 0.0 0.3 0.8 0.5 0.2 0.3 2.2

ENE 0.0 0.7 0.8 0.5 0.3 1.0 3.3

E 0.0 3.0 1.2 0.7 0.3 0.5 5.7

ESE 0.0 1.5 1.7 1.8 1.0 2.3 8.3

SE 0.0 0.3 1.3 2.3 1.7 4.5 10.2

SSE 0.0 0.0 0.2 0.3 2.2 4.2 6.8

S 0.0 0.2 0.5 1.5 0.8 4.0 7.0

SSW 0.0 0.0 0.0 1.2 0.8 3.8 5.8

SW 0.0 0.0 0.2 2.0 1.7 2.8 6.7

WSW 0.0 0.0 0.3 3.0 1.7 3.7 8.7

W 0.0 0.0 0.0 2.5 2.0 3.3 7.8

WNW 0.0 0.7 0.3 2.3 1.7 3.3 8.3

NW 0.0 0.2 0.8 3.0 1.8 2.0 7.8

NNW 0.0 0.7 0.7 1.0 1.0 1.7 5.0

All 0.0 8.7 10.0 24.5 17.8 39.0 100.0

Stability Class

Table 3: Frequency of Hourly Averaged Winds by Direction and Speed 

December 18, 2009 - January 11, 2010 

(percent of occurrence) 

 Calm (< 0.447 m/s) = 2.0% 

 Mean wind speed = 1.8 m/s 

 Data presented as direction from which wind is blowing. 

Table 4: Frequency of Hourly Averaged Winds by Direction and Stability 

December 18, 2009 - January 11, 2010 

(percent of occurrence) 

Mean

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

N 2.5 0.2 0.2 0.3 0.0 0.0 3.2 1.7

NNE 2.5 0.2 0.0 0.0 0.0 0.0 2.7 1.0

NE 1.8 0.0 0.0 0.0 0.0 0.0 1.8 1.0

ENE 3.0 0.3 0.0 0.0 0.0 0.0 3.3 1.1

E 2.7 2.7 0.3 0.0 0.0 0.0 5.7 1.5

ESE 3.5 4.0 0.8 0.0 0.0 0.0 8.3 1.8

SE 4.8 4.3 1.0 0.0 0.0 0.0 10.2 1.8

SSE 4.3 1.7 0.5 0.0 0.0 0.0 6.5 1.4

S 4.0 2.7 0.3 0.0 0.0 0.0 7.0 1.5

SSW 3.2 2.7 0.0 0.0 0.0 0.0 5.8 1.5

SW 2.7 2.7 1.2 0.2 0.0 0.0 6.7 2.1

WSW 4.2 2.3 1.2 1.0 0.0 0.0 8.7 2.2

W 4.2 3.2 0.5 0.0 0.0 0.0 7.8 1.7

WNW 3.8 3.0 0.8 0.2 0.2 0.0 8.0 2.0

NW 3.7 2.7 0.7 0.3 0.2 0.2 7.7 2.2

NNW 2.8 1.2 0.2 0.5 0.0 0.0 4.7 1.9

All 53.7 33.7 7.7 2.5 0.3 0.2 98.0 1.8

Speed Class Intervals (m/s)
Marigold Preliminary Hcn Monitoring Report.Docx 9 

Figure 4: Wind Frequency Distribution 

1%

2%

3%

4%

5%

6%

7%

8%

9%

10%

N

NNE

NE

ENE

E

ESE

SE

SSE

S

SSW

SW

WSW

W

WNW

NW

NNW

0.5 1 5 8 10 m/s

15-Minute Met Data

Wind Frequency Distribution: 12/18/09 - 01/11/10

Calm = 161 Missing = 0

Number of non-calm/missing = 2,239
Marigold Preliminary Hcn Monitoring Report.Docx 10 

2.2 Temperature 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 -3.8°C (25.2°F). The maximum hourly averaged 2-meter 

temperature was 7.6°C (45.7°F) and occurred on the afternoon of January 10, 2010. The minimum 

hourly averaged 2-meter temperature was -18.0°C (-0.4°F) and occurred on the morning of December 

26, 2009. 

Barometric pressure data collected during the sampling period are summarized in Table 5. The 

average barometric pressure for the period was 25.45 inHg (646 mmHg). The maximum hourly 

averaged barometric pressure for the period was 25.62 inHg (651 mmHg) and occurred for two 

consecutive hours in the morning of December 24, 2009. The minimum hourly averaged barometric 

pressure for the period was 25.01 inHg (635 mmHg) and occurred for four consecutive hours in the 

morning of December 22, 2009. 

Table 5: Temperature and Barometric Pressure 

December 18, 2009 - January 11, 2010 

Parameter 

Temperature 

(°C)

Barometric 

Pressure 

(inch Hg) 

Avg. -3.8 25.45 

Max. 7.6 25.62 

Min. -18.0 25.01 
Marigold Preliminary Hcn Monitoring Report.Docx 11 

SECTION 3 

HCN STATION 

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 (Storage and Retrieval of 

Aerometric Data) format. A summary of this data for each parameter is shown in the following 

sections. 

3.1 Winds 

Wind data is from the co-located meteorological station - see Section 2.1 above. 

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 -3.58°C (25.56°F). The maximum hourly averaged 2-meter 

temperature was 7.90°C (46.22°F) and occurred on the afternoon of December 18, 2009. The 

minimum hourly averaged 2-meter temperature was -17.49°C (0.52°F) and occurred on the morning 

of December 24, 2009. 

The relative humidity mean and extremes for the sampling period are presented in Table 6. The 

average relative humidity for the period was 45 percent. The minimum hourly average was 37 

percent and the maximum was 51 percent. 

As discussed in Section 1.3, the barometric pressure data from the co-located meteorological station 

was utilized during the sampling period (December 18, 2009, through January 11, 2010). Valid 

barometric pressure data from the HCN monitor station itself began collecting on January 15, 2010, at 

2:30 pm, following installation of a new sensor. 

Table 6: Temperature and Relative Humidity 

December 18, 2009 - January 11, 2010 

Parameter 

Temperature 

(°C)

Relative 

Humidity 

(%) 

Avg. -3.58 45 

Max. 7.90 51 

Min. -17.49 37 
Marigold Preliminary Hcn Monitoring Report.Docx 12 

3.3 HCN Concentration 

For the calculation of HCN concentration at standard conditions, 1 the barometric pressure from the 

meteorological station, which is co-located with the HCN monitor, was used. 

The HCN concentration data collected during the sampling period are summarized in Table 7. The 

average HCN concentration, corrected to standard conditions, was 2.27 μg/m3. The minimum HCN 

concentration for the period was 0.58 μg/m3 and occurred on December 30, 2009. The maximum 

HCN concentration for the period was 7.34 μg/m3 and occurred on December 18, 2009. 

Table 7: HCN Concentration 

December 18, 2009 - January 11, 2010 

(μg/m3) 

 HCN Concentration 

Run Day* 

Actual 

Conditions 

Standard 

Conditions 

12/18/2009 6.82 7.34 

12/21/2009 0.83 0.90 

12/24/2009 1.34 1.37 

12/27/2009 1.26 1.31 

12/30/2009 0.54 0.58 

01/02/2010 3.25 3.49 

01/05/2010 2.50 2.64 

01/08/2010 0.70 0.75 

01/11/2010 1.92 2.07 

Average 2.13 2.27 

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

The average HCN concentration of 2.27 μg/m3 is below the EPA lifetime exposure reference 

concentration of 3E-3 mg/m3.

2 The maximum HCN concentration of 7.34 μg/m3 is two orders of 

magnitude below the National Institute for Occupational Safety and Health (NIOSH) recommended 

short-term exposure limit of 4,700 ppb (5,190 μg/m3).3 In addition, the EPA reference concentration 

of 3E-3 mg/m3 was developed with a total uncertainty factor of 1,000, where the Lowest Observed 

Adverse Effect Level (LOAEL) was 7,070 μg/m3.

2 

 

1 Standard conditions are 1 atmosphere and 25°C. 

2 U.S. EPA Integrated Risk Information System. http://www.epa.gov/iris/subst/0060.htm. 

3 Occupational Safety and Health Guideline for Hydrogen Cyanide. 

http://www.osha.gov/SLTC/healthguidelines/hydrogencyanide/recognition.html 
Marigold Preliminary Hcn Monitoring Report.Docx 13 

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 that blow from 

206° through 244° (approximately south-southwest through west-southwest) travel from the potential 

HCN sources at the Marigold mine towards the HCN monitor. The percent of winds blowing within 

this range of directions on each sample day is shown in Table 8 and Figure 5. 

As shown by Table 8 and Figure 5, there does not appear to be a correlation between wind direction 

and measured HCN concentration. On the highest HCN concentration day, the winds blew from the 

potential HCN sources towards the monitor 21 percent of the time. However, on the lowest HCN 

concentration day, the winds blew from the potential HCN sources towards the monitor 42 percent of 

the time, which is the highest percent of winds blowing towards the monitor of any of the sample 

days. 

Table 8 also shows that there does not appear to be a correlation between wind speed and measured 

HCN concentration. The lowest and the second-highest HCN concentration days had the highest and 

second-highest average wind speed, respectively. 

Table 8: Measured HCN Concentration Analysis 

December 18, 2009 - January 11, 2010 

HCN 

Concentration 

Winds Blowing from HCN 

Sources towards Monitor 

Average Wind 

Speed 

Run Day (μg/m3) No. of Hours Percent (m/s) 

12/18/09 7.34 5 21 1.4 

12/21/09 0.90 2 8 1.8 

12/24/09 1.37 1 4 0.8 

12/27/09 1.31 1 4 1.0 

12/30/09 0.58 10 42 3.7 

01/02/10 3.49 3 13 2.2 

01/05/10 2.64 3 13 1.4 

01/08/10 0.75 0 0 2.0 

01/11/10 2.07 4 17 1.8 

Average 2.27 
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Figure 5: Measured HCN Concentration Analysis 

Figures 6 and 7 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 30, 2009. The highest HCN concentration was measured 

on December 18, 2009. The winds were predominately from the southwest to the west-southwest on 

the lowest concentration day and from the east-southeast to the southwest on the highest 

concentration day. 

0

5

10

15

20

25

30

35

40

45

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Percent of Winds (%)

HCN Concentration (μg/m3)

Run Day

HCN Concentration Percentof Winds Towards Monitor
Marigold Preliminary Hcn Monitoring Report.Docx 15 

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 5 8 10 m/s

15-Minute Met Data

Wind Frequency Distribution: 12/18/2009

Calm = 5 Missing = 0

Number of non-calm/missing = 91

4%

8%

12%

16%

20%

24%

28%

32%

36%

40%

N

NNE

NE

ENE

E

ESE

SE

SSE

S

SSW

SW

WSW

W

WNW

NW

NNW

0.5 1 5 8 10 m/s

15-Minute Met Data

Wind Frequency Distribution: 12/30/2009

Calm = 0 Missing = 0

Number of non-calm/missing = 96

Figure 6: Wind frequency for December 30, 2009 (Lowest Concentration Day) 

Figure 7: Wind frequency for December 18, 2009 (Highest Concentration Day) 
 

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 2

12/18/2009 1.3 1.8 1.2 0.8 1.4 1.1 1.6 0.8 1.2 1.5 1.5 1.3 0.8 1.0 1.0 1.8 2.8 2.5 2.0 2.4 1.6 112/19/2009 1.2 1.2 2.5 1.1 0.8 1.8 2.7 1.1 0.8 1.2 0.9 1.2 2.9 2.9 3.4 1.9 1.1 2.8 1.1 2.3 1.9 012/20/2009 1.4 2.3 1.2 2.2 2.2 1.9 1.5 1.3 2.0 1.1 2.9 2.1 3.9 3.6 3.0 2.1 2.4 2.0 1.5 0.9 1.2 212/21/2009 1.7 1.3 1.4 2.4 1.8 2.1 1.7 1.4 1.2 2.8 2.9 1.5 1.2 1.1 1.9 1.7 1.1 3.1 2.0 1.5 2.0 312/22/2009 1.1 1.9 2.8 4.6 3.6 7.1 10.0 9.1 6.7 6.1 5.1 6.2 5.2 6.3 5.9 4.0 3.0 4.8 5.2 3.6 2.7 212/23/2009 3.4 2.4 2.8 2.1 1.0 1.7 2.2 2.2 0.7 0.6 0.6 1.0 0.8 0.9 0.7 0.7 1.9 2.2 1.8 1.0 0.9 012/24/2009 0.8 0.6 1.2 0.9 0.9 0.7 1.0 0.8 0.4 0.6 0.3 0.6 0.8 0.9 0.4 0.5 0.8 1.1 0.8 0.9 1.6 112/25/2009 0.6 0.7 1.0 1.3 0.6 1.0 0.5 0.6 0.4 0.3 0.4 1.0 0.7 0.5 0.7 1.2 0.4 0.5 1.1 1.5 1.4 112/26/2009 1.5 1.3 1.1 2.1 0.5 0.9 0.7 0.3 0.6 0.5 1.0 0.8 1.0 1.5 1.9 1.0 0.7 0.7 1.2 1.9 0.5 012/27/2009 0.6 0.8 0.4 1.0 1.2 1.9 0.5 1.0 1.0 1.2 1.0 0.7 1.7 1.1 1.2 0.9 0.9 0.3 0.8 0.7 0.8 112/28/2009 1.2 1.4 0.6 1.3 0.8 1.9 2.0 0.7 0.5 0.8 0.5 0.6 0.8 1.4 1.3 0.8 1.3 1.0 0.7 0.8 2.1 112/29/2009 1.2 1.7 1.0 0.3 0.7 0.6 0.9 0.6 2.0 1.6 1.4 1.7 2.1 1.7 1.3 1.3 1.0 1.6 2.4 4.2 2.1 112/30/2009 3.0 2.6 3.7 4.7 2.6 3.5 2.3 3.8 4.3 3.9 4.3 4.2 3.9 4.1 4.0 1.7 4.1 4.8 5.2 4.7 4.0 312/31/2009 0.8 1.3 2.8 1.1 1.6 1.7 1.4 0.9 1.5 1.9 1.8 3.4 1.8 2.4 2.0 2.2 0.9 1.6 0.7 1.0 2.1 2

1/1/2010 2.1 2.9 1.4 1.2 0.8 0.9 2.5 1.7 1.2 2.7 2.3 1.5 1.1 1.9 1.4 1.1 1.7 1.7 2.3 2.5 5.0 61/2/2010 5.7 5.1 3.7 4.8 3.7 3.5 1.8 1.7 1.1 1.1 2.3 1.4 2.0 1.9 1.2 0.6 1.5 1.3 1.3 1.9 1.0 01/3/2010 1.1 0.9 1.1 1.3 0.8 1.3 1.1 0.8 0.5 0.9 1.5 1.5 1.5 1.5 1.7 1.7 0.7 0.7 1.5 0.7 1.4 01/4/2010 1.4 1.1 1.5 1.2 0.8 1.2 0.9 0.5 1.2 1.7 1.8 1.7 4.0 3.1 1.9 1.4 1.0 0.8 1.8 1.0 1.3 11/5/2010 1.5 1.7 1.1 1.0 0.9 1.7 0.9 1.1 1.4 1.6 1.6 1.8 1.2 1.4 1.5 1.5 2.6 1.3 0.9 2.0 2.0 01/6/2010 1.1 0.7 1.1 0.9 1.1 1.3 1.3 1.0 1.1 0.6 0.5 1.2 1.3 1.4 0.9 1.0 1.4 1.4 1.1 1.4 1.7 21/7/2010 1.2 1.2 1.5 2.1 2.5 1.4 1.0 1.9 2.5 2.3 2.7 1.9 1.5 1.8 2.0 1.3 1.5 0.6 1.4 2.8 2.7 21/8/2010 1.0 1.3 2.3 2.5 1.0 1.0 1.2 0.9 0.8 1.4 4.0 2.9 2.3 3.3 4.0 3.6 2.6 2.3 1.1 1.0 1.4 01/9/2010 3.0 3.0 1.4 2.6 1.5 2.3 0.9 1.1 1.0 1.2 0.5 1.1 2.1 1.6 1.3 1.1 0.9 1.8 0.9 1.5 2.3 1

1/10/2010 0.8 1.5 1.6 1.3 1.1 1.6 1.1 2.2 1.3 1.8 1.4 1.1 1.4 1.3 2.0 1.6 1.9 1.2 1.6 2.0 2.7 11/11/2010 1.5 1.4 1.7 1.5 1.9 1.3 0.9 1.0 1.8 0.8 2.6 1.8 2.5 1.9 1.5 3.1 1.9 1.2 2.1 2.2 1.5 1

Avg 1.6 1.7 1.7 1.9 1.4 1.8 1.7 1.5 1.5 1.6 1.8 1.8 1.9 2.0 1.9 1.6 1.6 1.7 1.7 1.9 1.9 1

Max 5.7 5.1 3.7 4.8 3.7 7.1 10.0 9.1 6.7 6.1 5.1 6.2 5.2 6.3 5.9 4.0 4.1 4.8 5.2 4.7 5.0 6

Min 0.6 0.6 0.4 0.3 0.5 0.6 0.5 0.3 0.4 0.3 0.3 0.6 0.7 0.5 0.4 0.5 0.4 0.3 0.7 0.7 0.5 0

SAROAD for Marigold, MarigoldHCN

Channel: WS_ms_10m

Month: 12/18/09 ‐ 01/11/10

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 

12/18/2009 174 170 182 268 301 309 177 101 159 305 39 2 354 130 179 124 176 213 215 226 219 12/19/2009 192 317 283 318 228 248 276 129 308 350 20 105 120 115 119 116 137 203 261 229 198 12/20/2009 285 280 250 327 258 299 254 268 309 247 119 172 136 126 122 202 123 291 157 64 160 12/21/2009 257 258 242 141 239 293 283 74 138 131 323 329 299 113 127 114 51 300 16 198 261 12/22/2009 140 179 222 308 288 305 304 304 294 313 331 342 345 359 351 350 305 310 317 337 270 12/23/2009 254 260 240 142 54 170 215 312 75 101 349 55 352 81 38 34 255 180 173 188 164 12/24/2009 152 339 300 150 148 174 211 91 334 351 2 59 66 45 21 92 280 295 187 206 113 12/25/2009 6 291 262 120 197 150 240 108 35 11 38 69 16 84 12 46 287 225 281 228 142 12/26/2009 144 153 281 306 222 173 166 168 175 322 19 322 7 333 297 36 160 265 287 280 210 12/27/2009 67 239 319 350 313 303 307 132 129 23 334 15 92 80 81 24 56 154 181 259 261 12/28/2009 226 283 152 150 349 284 158 209 85 78 352 55 336 303 326 304 288 228 162 237 123 12/29/2009 337 307 338 335 289 261 201 127 354 104 114 94 105 111 104 171 206 197 235 222 157 12/30/2009 158 175 244 261 235 236 296 283 244 237 247 288 290 317 325 294 264 236 230 226 220 12/31/2009 168 163 171 325 201 177 117 124 125 126 61 120 137 126 136 139 311 339 317 127 144 

1/1/2010 149 139 342 227 119 127 122 110 177 105 118 119 88 122 8 59 198 222 192 199 249 1/2/2010 256 248 259 239 251 215 150 182 198 104 108 109 118 107 71 187 261 249 257 289 267 1/3/2010 276 171 136 179 123 257 168 162 356 273 87 77 86 94 91 314 283 188 247 208 173 1/4/2010 133 324 342 261 227 299 240 28 139 113 100 119 124 95 91 349 277 272 264 145 236 1/5/2010 223 298 257 335 303 294 215 315 300 178 99 91 86 136 104 333 240 141 108 158 73 1/6/2010 30 206 166 18 252 286 63 204 50 68 112 118 77 89 57 313 295 310 229 311 211 1/7/2010 118 288 253 262 295 337 252 258 271 318 339 337 308 344 338 321 309 248 241 269 280 1/8/2010 155 60 308 300 245 264 264 332 160 321 118 125 137 127 126 119 127 136 313 296 245 1/9/2010 130 141 159 281 317 258 188 272 343 62 150 100 96 97 31 21 30 279 234 234 248 

1/10/2010 236 117 127 158 203 163 337 307 303 318 355 94 96 84 98 79 310 271 177 196 203 1/11/2010 202 30 297 344 217 240 118 292 323 187 117 244 183 223 298 99 97 246 217 248 271 

Max 337 339 342 350 349 337 337 332 356 351 355 342 354 359 351 350 311 339 317 337 280 

Min 6 30 127 18 54 127 63 28 35 11 2 2 7 45 8 21 30 136 16 64 73 

SAROAD for Marigold, MarigoldHCN

Channel: WD_10m

Month: 12/18/09 ‐ 01/11/10

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 22 

12/18/2009 0.8 1.1 1.1 0.2 ‐0.8 ‐0.7 ‐1.2 ‐1.5 0.6 3.0 3.8 4.7 5.8 6.4 6.8 6.4 2.4 0.8 0.5 0.0 ‐0.3 ‐1.2 

12/19/2009 ‐1.7 ‐2.0 ‐2.1 ‐4.1 ‐4.3 ‐3.7 ‐5.1 ‐4.6 ‐3.2 ‐2.6 ‐2.0 0.7 2.6 3.1 4.3 3.2 1.0 ‐0.6 ‐0.9 ‐1.5 ‐1.6 ‐2.1 

12/20/2009 ‐3.3 ‐2.8 ‐3.6 ‐4.5 ‐4.8 ‐4.6 ‐6.2 ‐4.6 ‐3.5 ‐3.9 ‐1.0 0.8 1.4 1.1 1.2 1.3 0.4 ‐1.2 ‐1.3 ‐1.3 ‐1.6 ‐2.4 

12/21/2009 ‐3.3 ‐4.2 ‐4.1 ‐2.5 ‐3.5 ‐4.8 ‐4.3 ‐3.8 ‐2.0 0.3 0.0 0.6 2.4 3.3 2.9 2.8 1.5 0.8 0.5 0.0 ‐0.1 ‐0.1 

12/22/2009 0.0 ‐0.5 ‐0.3 ‐0.6 ‐1.3 ‐2.5 ‐3.5 ‐4.5 ‐4.8 ‐4.4 ‐3.8 ‐3.6 ‐3.3 ‐3.4 ‐3.8 ‐4.9 ‐6.8 ‐6.2 ‐6.5 ‐7.5 ‐7.6 ‐7.7 

12/23/2009 ‐7.7 ‐8.5 ‐10.4 ‐9.4 ‐9.1 ‐11.2 ‐12.4 ‐12.1 ‐13.5 ‐9.7 ‐8.0 ‐7.1 ‐6.0 ‐5.2 ‐4.6 ‐4.8 ‐8.9 ‐10.2 ‐10.4 ‐11.7 ‐11.6 ‐10.5 

12/24/2009 ‐12.8 ‐12.7 ‐13.7 ‐14.0 ‐14.8 ‐16.0 ‐15.5 ‐17.1 ‐15.3 ‐13.9 ‐11.8 ‐10.3 ‐9.0 ‐7.5 ‐6.9 ‐6.8 ‐9.5 ‐10.7 ‐13.6 ‐13.4 ‐11.8 ‐13.6 

12/25/2009 ‐13.0 ‐13.9 ‐14.5 ‐15.5 ‐17.1 ‐16.2 ‐15.7 ‐17.4 ‐16.2 ‐14.7 ‐13.5 ‐11.2 ‐10.3 ‐8.4 ‐7.3 ‐7.7 ‐10.7 ‐11.8 ‐11.9 ‐13.9 ‐12.9 ‐13.6 

12/26/2009 ‐15.1 ‐14.7 ‐14.6 ‐14.7 ‐15.4 ‐18.0 ‐16.9 ‐16.6 ‐16.3 ‐13.9 ‐12.5 ‐10.1 ‐8.0 ‐7.1 ‐6.0 ‐5.7 ‐9.7 ‐11.2 ‐9.9 ‐10.0 ‐11.0 ‐11.3 

12/27/2009 ‐10.1 ‐10.4 ‐10.2 ‐10.5 ‐12.0 ‐12.3 ‐10.6 ‐10.6 ‐9.4 ‐8.4 ‐8.6 ‐7.2 ‐5.0 ‐3.9 ‐3.2 ‐3.1 ‐4.3 ‐5.6 ‐7.9 ‐9.1 ‐10.4 ‐11.2 

12/28/2009 ‐11.0 ‐10.7 ‐12.1 ‐12.3 ‐11.4 ‐10.5 ‐13.1 ‐11.7 ‐11.2 ‐9.3 ‐7.7 ‐6.2 ‐5.1 ‐4.7 ‐4.4 ‐4.7 ‐6.0 ‐7.0 ‐6.6 ‐6.2 ‐6.1 ‐5.3 

12/29/2009 ‐5.7 ‐5.6 ‐6.6 ‐7.2 ‐7.1 ‐6.8 ‐6.4 ‐6.1 ‐5.5 ‐5.3 ‐4.1 ‐3.1 ‐2.8 ‐2.0 ‐1.9 ‐3.4 ‐4.0 ‐4.2 ‐3.2 ‐2.7 ‐3.2 ‐3.8 

12/30/2009 ‐1.7 ‐2.5 ‐1.2 ‐1.6 ‐0.9 ‐0.9 ‐1.0 ‐0.6 ‐0.5 ‐0.4 0.5 1.1 1.3 1.1 0.6 ‐0.1 ‐1.9 ‐2.8 ‐2.3 ‐2.9 ‐4.0 ‐5.5 

12/31/2009 ‐8.5 ‐10.1 ‐11.7 ‐11.8 ‐12.0 ‐11.4 ‐11.9 ‐12.6 ‐9.2 ‐7.1 ‐5.6 ‐4.9 ‐3.7 ‐3.7 ‐3.0 ‐2.7 ‐3.0 ‐3.7 ‐4.1 ‐4.1 ‐4.0 ‐3.3 

1/1/2010 ‐4.0 ‐3.9 ‐3.6 ‐4.4 ‐3.9 ‐4.3 ‐3.1 ‐3.9 ‐2.9 ‐1.2 0.0 1.2 1.8 1.9 2.7 2.0 1.7 2.4 4.2 1.3 1.9 2.4 

1/2/2010 2.0 2.4 1.1 1.8 0.5 ‐1.2 ‐2.4 ‐2.2 0.2 2.2 2.7 2.9 3.3 3.3 3.7 2.4 ‐1.9 ‐4.0 ‐3.3 ‐0.4 0.0 ‐1.8 

1/3/2010 ‐4.6 ‐5.9 ‐6.6 ‐7.0 ‐6.4 ‐7.8 ‐8.5 ‐9.1 ‐8.7 ‐5.0 ‐4.1 ‐2.5 ‐1.1 0.0 1.4 ‐0.4 ‐2.6 ‐5.6 ‐5.3 ‐5.4 ‐6.2 ‐5.6 

1/4/2010 ‐7.3 ‐8.5 ‐7.8 ‐10.0 ‐9.7 ‐10.7 ‐10.8 ‐10.4 ‐8.2 ‐5.9 ‐4.7 ‐1.4 0.2 0.4 0.7 ‐0.4 ‐4.2 ‐5.5 ‐4.4 ‐4.8 ‐4.9 ‐6.2 

1/5/2010 ‐7.8 ‐7.9 ‐7.0 ‐5.9 ‐6.1 ‐7.6 ‐7.7 ‐7.9 ‐7.1 ‐4.2 ‐3.1 ‐2.1 ‐1.6 ‐1.1 ‐0.1 ‐1.3 ‐3.3 ‐3.9 ‐3.5 ‐2.3 ‐2.4 ‐2.9 

1/6/2010 ‐3.5 ‐4.1 ‐3.5 ‐5.0 ‐4.0 ‐3.6 ‐4.6 ‐3.6 ‐2.3 ‐2.0 ‐0.3 1.0 2.2 2.7 2.6 1.8 1.3 0.8 0.8 0.9 0.6 1.3 

1/7/2010 0.3 0.1 0.1 0.9 0.9 0.5 0.5 1.1 1.8 2.7 2.5 2.8 3.2 3.6 3.5 3.3 2.3 1.1 0.4 0.5 ‐0.2 ‐0.9 

1/8/2010 ‐2.7 ‐3.3 ‐3.5 ‐4.5 ‐4.7 ‐4.8 ‐4.9 ‐5.5 ‐4.7 ‐2.5 ‐1.3 ‐0.2 0.5 0.6 0.7 0.5 0.3 ‐0.1 0.0 ‐0.3 0.3 0.0 

1/9/2010 ‐0.3 ‐0.2 0.0 ‐1.1 ‐1.9 ‐2.5 ‐2.7 ‐3.1 ‐1.0 ‐0.4 1.1 3.1 4.6 4.7 4.1 3.8 2.7 0.4 0.2 ‐0.2 0.2 0.4 

1/10/2010 ‐0.6 0.3 0.7 0.8 0.5 ‐0.2 ‐1.5 ‐1.4 ‐0.2 0.0 2.3 3.7 5.9 6.8 7.5 7.6 4.6 2.1 0.9 0.5 0.6 0.7 

1/11/2010 ‐0.3 ‐0.7 ‐1.1 ‐1.7 ‐2.3 ‐0.6 ‐1.5 ‐1.7 ‐1.5 ‐0.2 2.3 3.4 5.1 5.1 5.4 5.3 3.9 2.4 2.3 2.2 1.1 2.1 

Avg ‐4.9 ‐5.2 ‐5.4 ‐5.8 ‐6.1 ‐6.5 ‐6.8 ‐6.9 ‐5.8 ‐4.3 ‐3.1 ‐1.7 ‐0.6 ‐0.1 0.3 ‐0.2 ‐2.2 ‐3.3 ‐3.4 ‐3.7 ‐3.8 ‐4.1 

Max 2.0 2.4 1.1 1.8 0.9 0.5 0.5 1.1 1.8 3.0 3.8 4.7 5.9 6.8 7.5 7.6 4.6 2.4 4.2 2.2 1.9 2.4 

Min ‐15.1 ‐14.7 ‐14.6 ‐15.5 ‐17.1 ‐18.0 ‐16.9 ‐17.4 ‐16.3 ‐14.7 ‐13.5 ‐11.2 ‐10.3 ‐8.4 ‐7.3 ‐7.7 ‐10.7 ‐11.8 ‐13.6 ‐13.9 ‐12.9 ‐13.6 

SAROAD for Marigold, MarigoldHCN

Channel: Temp_2m_C

Month: 12/18/09 ‐ 01/11/10

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 2

12/18/2009 25.53 25.52 25.52 25.53 25.53 25.55 25.55 25.55 25.55 25.57 25.57 25.57 25.55 25.54 25.54 25.54 25.53 25.53 25.53 25.53 25.54 25

12/19/2009 25.54 25.54 25.54 25.54 25.54 25.53 25.53 25.53 25.53 25.54 25.53 25.52 25.51 25.48 25.47 25.48 25.48 25.47 25.47 25.47 25.47 2512/20/2009 25.44 25.43 25.43 25.41 25.40 25.40 25.40 25.40 25.39 25.40 25.38 25.38 25.35 25.32 25.32 25.33 25.32 25.32 25.32 25.33 25.33 2512/21/2009 25.32 25.33 25.33 25.30 25.29 25.29 25.29 25.27 25.27 25.26 25.24 25.23 25.19 25.16 25.15 25.12 25.10 25.09 25.09 25.07 25.08 2512/22/2009 25.02 25.01 25.01 25.01 25.01 25.02 25.03 25.06 25.08 25.10 25.11 25.12 25.12 25.14 25.16 25.19 25.22 25.24 25.26 25.29 25.31 2512/23/2009 25.37 25.41 25.43 25.44 25.46 25.48 25.48 25.49 25.51 25.54 25.55 25.54 25.54 25.52 25.53 25.53 25.53 25.54 25.55 25.56 25.56 2512/24/2009 25.59 25.59 25.61 25.59 25.59 25.60 25.60 25.60 25.61 25.62 25.62 25.61 25.59 25.58 25.58 25.57 25.56 25.57 25.56 25.55 25.55 2512/25/2009 25.53 25.53 25.53 25.52 25.51 25.50 25.50 25.51 25.52 25.53 25.52 25.50 25.48 25.46 25.44 25.44 25.44 25.43 25.43 25.43 25.43 2512/26/2009 25.41 25.41 25.41 25.40 25.40 25.39 25.39 25.39 25.40 25.42 25.42 25.40 25.38 25.36 25.35 25.35 25.35 25.35 25.35 25.36 25.37 2512/27/2009 25.39 25.39 25.40 25.40 25.39 25.39 25.40 25.41 25.43 25.44 25.45 25.45 25.44 25.45 25.45 25.46 25.46 25.47 25.48 25.47 25.48 2512/28/2009 25.50 25.50 25.51 25.50 25.50 25.50 25.50 25.49 25.49 25.49 25.48 25.45 25.43 25.40 25.38 25.37 25.36 25.35 25.34 25.34 25.33 2512/29/2009 25.30 25.30 25.31 25.30 25.29 25.29 25.29 25.30 25.32 25.33 25.34 25.33 25.32 25.30 25.29 25.29 25.29 25.29 25.28 25.29 25.27 2512/30/2009 25.22 25.23 25.24 25.24 25.24 25.25 25.27 25.29 25.31 25.33 25.34 25.35 25.35 25.36 25.38 25.40 25.41 25.43 25.45 25.47 25.49 2512/31/2009 25.53 25.54 25.55 25.55 25.54 25.54 25.54 25.54 25.54 25.55 25.56 25.55 25.53 25.51 25.50 25.50 25.51 25.51 25.52 25.53 25.53 25

1/1/2010 25.54 25.53 25.53 25.52 25.51 25.51 25.51 25.53 25.54 25.54 25.54 25.52 25.51 25.48 25.45 25.44 25.43 25.43 25.44 25.43 25.43 251/2/2010 25.44 25.45 25.47 25.49 25.47 25.48 25.50 25.51 25.52 25.53 25.54 25.52 25.50 25.49 25.49 25.49 25.49 25.50 25.52 25.53 25.54 251/3/2010 25.54 25.54 25.55 25.54 25.54 25.55 25.56 25.56 25.57 25.58 25.58 25.57 25.55 25.53 25.52 25.53 25.53 25.52 25.53 25.53 25.53 251/4/2010 25.52 25.51 25.51 25.51 25.50 25.50 25.50 25.51 25.52 25.54 25.54 25.51 25.48 25.48 25.47 25.47 25.47 25.47 25.49 25.48 25.48 251/5/2010 25.48 25.49 25.49 25.48 25.47 25.47 25.47 25.47 25.50 25.50 25.50 25.49 25.48 25.46 25.45 25.46 25.46 25.46 25.47 25.47 25.48 251/6/2010 25.48 25.48 25.48 25.47 25.47 25.46 25.47 25.47 25.48 25.49 25.49 25.48 25.47 25.46 25.46 25.47 25.47 25.47 25.48 25.48 25.49 251/7/2010 25.48 25.48 25.49 25.49 25.49 25.49 25.49 25.49 25.50 25.52 25.54 25.52 25.51 25.50 25.50 25.50 25.51 25.52 25.52 25.52 25.52 251/8/2010 25.53 25.52 25.51 25.52 25.51 25.50 25.50 25.51 25.52 25.54 25.53 25.52 25.50 25.49 25.49 25.49 25.50 25.51 25.51 25.52 25.53 251/9/2010 25.55 25.55 25.55 25.54 25.54 25.54 25.54 25.56 25.58 25.59 25.59 25.58 25.55 25.53 25.53 25.53 25.52 25.52 25.53 25.53 25.52 25

1/10/2010 25.52 25.52 25.54 25.54 25.54 25.54 25.55 25.55 25.55 25.57 25.57 25.56 25.54 25.53 25.53 25.53 25.53 25.54 25.55 25.55 25.56 251/11/2010 25.58 25.57 25.57 25.56 25.55 25.54 25.54 25.54 25.55 25.55 25.54 25.51 25.48 25.46 25.45 25.44 25.42 25.42 25.41 25.41 25.41 25

Avg 25.45 25.45 25.46 25.45 25.45 25.45 25.46 25.46 25.47 25.48 25.48 25.47 25.45 25.44 25.44 25.44 25.44 25.44 25.44 25.45 25.45 25

Max 25.59 25.59 25.61 25.59 25.59 25.60 25.60 25.60 25.61 25.62 25.62 25.61 25.59 25.58 25.58 25.57 25.56 25.57 25.56 25.56 25.56 25

Min 25.02 25.01 25.01 25.01 25.01 25.02 25.03 25.06 25.08 25.10 25.11 25.12 25.12 25.14 25.15 25.12 25.10 25.09 25.09 25.07 25.08 25

SAROAD for Marigold, MarigoldHCN

Channel: BP_inHg_2m

Month: 12/18/09 ‐ 01/11/10

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 

12/18/2009 ‐0.15 ‐0.07 ‐0.19 ‐0.30 ‐0.33 ‐0.97 ‐1.83 ‐1.63 ‐2.21 ‐2.39 ‐1.24 1.12 3.19 4.83 6.46 7.69 7.90 6.87 3.06 ‐0.29 ‐1.19 ‐

12/19/200912/20/200912/21/2009 ‐4.31 ‐4.44 ‐4.61 ‐4.98 ‐5.50 ‐4.71 ‐4.29 ‐5.56 ‐5.19 ‐4.44 ‐3.52 ‐1.17 0.15 0.24 1.92 3.07 2.63 2.17 1.33 0.19 ‐0.41 ‐

12/22/200912/23/200912/24/2009 ‐14.09 ‐13.94 ‐14.35 ‐15.23 ‐15.11 ‐15.99 ‐16.06 ‐16.74 ‐17.27 ‐17.49 ‐16.01 ‐13.20 ‐9.91 ‐7.02 ‐5.45 ‐4.40 ‐4.02 ‐4.74 ‐8.34 ‐12.37 ‐14.28 ‐

12/25/200912/26/200912/27/2009 ‐10.16 ‐11.22 ‐11.60 ‐11.49 ‐12.14 ‐13.52 ‐12.40 ‐11.38 ‐9.90 ‐7.89 ‐6.92 ‐5.40 ‐3.08 ‐2.48 ‐1.05 ‐0.95 ‐3.75 ‐5.78 ‐8.44 ‐10.35 ‐12.07 ‐

12/28/200912/29/200912/30/2009 ‐2.92 ‐3.07 ‐2.54 ‐2.53 ‐2.15 ‐2.02 ‐1.80 ‐1.62 ‐1.26 ‐0.62 0.66 1.74 2.19 2.55 1.76 ‐0.34 ‐2.81 ‐4.60 ‐4.28 ‐4.71 ‐5.92 ‐

12/31/2009

1/1/20101/2/2010 ‐0.01 0.91 ‐0.15 ‐0.70 ‐0.60 ‐3.02 ‐4.51 ‐4.75 ‐2.86 1.34 4.19 4.64 4.89 4.10 4.54 2.44 ‐2.18 ‐5.38 ‐5.68 ‐2.98 ‐1.63 ‐

1/3/20101/4/20101/5/2010 ‐9.50 ‐9.58 ‐9.06 ‐7.15 ‐6.71 ‐7.96 ‐8.53 ‐8.76 ‐7.69 ‐5.08 ‐2.38 ‐0.68 ‐0.21 0.02 0.45 ‐0.89 ‐3.90 ‐5.25 ‐5.10 ‐3.67 ‐3.02 ‐

1/6/20101/7/20101/8/2010 ‐3.58 ‐4.68 ‐4.57 ‐5.26 ‐6.05 ‐6.39 ‐6.23 ‐6.45 ‐5.66 ‐3.61 ‐2.09 ‐0.63 0.43 0.56 0.64 0.22 ‐0.16 ‐0.55 ‐0.78 ‐0.68 ‐0.44 ‐

1/9/2010

1/10/20101/11/2010 ‐1.88 ‐2.36 ‐2.57 ‐2.99 ‐3.21 ‐2.24 ‐1.93 ‐2.32 ‐1.91 ‐1.29 0.94 2.23 4.17 4.81 5.03 5.08 3.28 1.22 0.46 0.68 ‐0.09 

Avg ‐5.18 ‐5.38 ‐5.51 ‐5.63 ‐5.76 ‐6.31 ‐6.40 ‐6.58 ‐5.99 ‐4.61 ‐2.93 ‐1.26 0.20 0.85 1.59 1.33 ‐0.33 ‐1.78 ‐3.08 ‐3.80 ‐4.34 ‐

Max ‐0.01 0.91 ‐0.15 ‐0.30 ‐0.33 ‐0.97 ‐1.80 ‐1.62 ‐1.26 1.34 4.19 4.64 4.89 4.83 6.46 7.69 7.90 6.87 3.06 0.68 ‐0.09 

Min ‐14.09 ‐13.94 ‐14.35 ‐15.23 ‐15.11 ‐15.99 ‐16.06 ‐16.74 ‐17.27 ‐17.49 ‐16.01 ‐13.20 ‐9.91 ‐7.02 ‐5.45 ‐4.40 ‐4.02 ‐5.78 ‐8.44 ‐12.37 ‐14.28 ‐

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

SAROAD for Marigold, MarigoldHCN

Channel: T_AMB_C

Month: 12/18/09 ‐ 01/11/10

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 

12/18/2009 42 42 42 42 42 42 43 42 42 42 42 43 43 44 45 46 46 47 46 46 45 12/19/200912/20/200912/21/2009 43 43 43 43 43 43 42 43 43 42 42 42 42 44 43 43 43 44 44 45 44 12/22/200912/23/200912/24/2009 38 38 38 38 38 38 37 37 37 38 40 41 42 43 44 47 47 48 46 44 42 12/25/200912/26/200912/27/2009 40 40 41 41 40 40 40 40 40 40 40 40 40 42 45 46 45 44 44 43 43 12/28/200912/29/200912/30/2009 42 43 43 43 43 43 43 43 43 43 44 44 46 50 49 47 47 46 46 45 45 12/31/2009

1/1/20101/2/2010 46 45 46 47 46 47 47 47 47 46 46 46 47 48 50 50 50 50 49 46 46 1/3/20101/4/20101/5/2010 46 46 46 46 46 46 46 46 46 45 45 46 46 46 47 49 50 49 48 47 47 1/6/20101/7/20101/8/2010 47 47 47 46 47 47 46 46 47 46 46 47 47 47 48 48 48 48 48 48 48 1/9/2010

1/10/20101/11/2010 48 49 49 49 49 48 48 49 49 49 48 48 48 49 50 50 51 51 51 50 50 

Avg 44 44 44 44 44 44 44 44 44 44 44 44 45 46 47 47 48 48 47 46 46 

Max 48 49 49 49 49 48 48 49 49 49 48 48 48 50 50 50 51 51 51 50 50 

Min 38 38 38 38 38 38 37 37 37 38 40 40 40 42 43 43 43 44 44 43 42 

Non‐Run‐DayNon‐Run‐Day

SAROAD for Marigold, MarigoldHCN

Channel: RH_percent

Month: 12/18/09 ‐ 01/11/10

Hour of da

y

Non‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐DayNon‐Run‐Day
APPENDIX B 

HCN Data 
Page 1 of 2

Wed, 01/06/10 5:23 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 January 06, 2010

Project Manager Rand Potter

Workorder: 1000413

Purchase Order:

Client Project ID: Air Sciences Inc 010410

235-3-5

Analytical Results

12/18/2009

1000413001 1/4/2010

Sample ID:

Lab ID:

Media: Collected:

Received:

235312182009-1 SKC 226-28, Soda Lime-200/600

Sampling Location: Marigold

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 1/6/2010

RL (ug/sample)

Hydrogen Cyanide 12 NA NA 0.21

12/18/2009

1000413002 1/4/2010

Sample ID:

Lab ID:

Media: Collected:

Received:

235312212009-2 SKC 226-28, Soda Lime-200/600

Sampling Location: Marigold

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 1/6/2010

RL (ug/sample)

Hydrogen Cyanide 1.6 NA NA 0.21

12/18/2009

1000413003 1/4/2010

Sample ID:

Lab ID:

Media: Collected:

Received:

235312242009-3 SKC 226-28, Soda Lime-200/600

Sampling Location: Marigold

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 1/6/2010

RL (ug/sample)

Hydrogen Cyanide 2.3 NA NA 0.21

12/18/2009

1000413004 1/4/2010

Sample ID:

Lab ID:

Media: Collected:

Received:

235312272009-1 SKC 226-28, Soda Lime-200/600

Sampling Location: Marigold

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 1/6/2010

RL (ug/sample)

Hydrogen Cyanide 2.3 NA NA 0.21

Sample Comments

1000413001 The back section had a reportable result indicating that the sampler may have been

overloaded. Results may be less than acutal.

1000413003 The back section had a reportable result indicating that the sampler may have been

overloaded. Results may be less than acutal.

Results Continued on Next Page

IHREP-V9.8
Page 2 of 2

Wed, 01/06/10 5:23 PM

ANALYTICAL REPORT

Project Manager Rand Potter

Workorder: 1000413

Purchase Order:

Client Project ID: Air Sciences Inc 010410

235-3-5

Analytical Results

1000413004 The back section had a reportable result indicating that the sampler may have been

overloaded. Results may be less than acutal.

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-V9.8

Page 1 of 2

Wed, 01/13/10 2:13 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 January 13, 2010

Project Manager Rand Potter

Workorder: 1000614

Purchase Order:

Client Project ID: Marigold 235-3-5 010610

235-3-5

Analytical Results

12/30/2009

1000614001 1/6/2010

Sample ID:

Lab ID:

Media: Collected:

Received:

235312302009-2 SKC 226-28, Soda Lime-200/600

Sampling Location: Marigold

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 1/12/2010

RL (ug/sample)

Hydrogen Cyanide 1.1 NA NA 0.21

1/2/2010

1000614002 1/6/2010

Sample ID:

Lab ID:

Media: Collected:

Received:

2353122010-3 SKC 226-28, Soda Lime-200/600

Sampling Location: Marigold

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 1/12/2010

RL (ug/sample)

Hydrogen Cyanide 7.0 NA NA 0.21

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

IHREP-V9.8
Page 2 of 2

Wed, 01/13/10 2:13 PM

ANALYTICAL REPORT

Project Manager Rand Potter

Workorder: 1000614

Purchase Order:

Client Project ID: Marigold 235-3-5 010610

235-3-5

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-V9.8


Page 1 of 2

Wed, 01/20/10 1:22 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 January 20, 2010

Project Manager Rand Potter

Workorder: 1001538

Purchase Order:

Client Project ID: Air Sciences, INC 011510

235-3-5

Analytical Results

1/5/2010

1001538001 1/15/2010

Sample ID:

Lab ID:

Media: Collected:

Received:

2353152010-1 SKC 226-28, Soda Lime-200/600

Sampling Location: Marigold

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 1/19/2010

RL (ug/sample)

Hydrogen Cyanide 4.6 NA NA 0.21

1/8/2010

1001538002 1/15/2010

Sample ID:

Lab ID:

Media: Collected:

Received:

2353182010-2 SKC 226-28, Soda Lime-200/600

Sampling Location: Marigold

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 1/19/2010

RL (ug/sample)

Hydrogen Cyanide 1.3 NA NA 0.21

1/11/2010

1001538003 1/15/2010

Sample ID:

Lab ID:

Media: Collected:

Received:

23531112010-3 SKC 226-28, Soda Lime-200/600

Sampling Location: Marigold

Method:

Analyte ug/sample mg/m3 ppm

NIOSH 6010 Analyzed: 1/19/2010

RL (ug/sample)

Hydrogen Cyanide 3.2 NA NA 0.21

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

IHREP-V9.8
Page 2 of 2

Wed, 01/20/10 1:22 PM

ANALYTICAL REPORT

Project Manager Rand Potter

Workorder: 1001538

Purchase Order:

Client Project ID: Air Sciences, INC 011510

235-3-5

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-V9.8


APPENDIX C 

Site Check Forms, Audits, and Calibration 
Calibration Form 

Marigold Air Quality and Meteorological Monitoring 

Site: Marigold Technician: Brian Smith 

Date: 12/16/2009 Site Conditions: Cold, Clear 

Invalid Data Range: Before 12/16/2009 Logger Serial Number: 2965 

Initial Prior to Departure Initials 

[] [] Data download (record date and time). BWS 

[] [] Time and date verified on datalogger. BWS 

[] [] Communications verified. BWS 

[] [] All public real-time values are confirmed and as expected. BWS 

0 WS/WD verification performed (complete audit form). N/A 

[] Temperature and RH verification performed (complete audit form). BWS 

0 Precipitation verification performed (complete audit form). N/A 

Barometric pressure verification performed (complete audit form). BWS 

~ Solar panel cleaned. BWS 

Comments: 

Site was installed and became operational on 12/16/2009 

All sensors were calibrated 

12/16/2009 

Date: 

235-3-12162009CALAQ-MET 1 
,\ I IZ ~ ( II "( -I \ I"'­

Calibration Form 

Marigold Air Quality and Meteorological Monitoring 

Temperature and Relative Humidity - Co-Located Calibration 

Time: 13:00 to 14:00 PST 

Relative Humidity Measured 

Diff HM P45C Logger VWR Thermo Hygro 

SN: D3250873 SN- 80357103 

0.1 1. 15 1. 17 

0.2 2. 15 2. 17 

0.1 3. 16 3. 17 

0.1 4. 17 4. 18 

0.0 5. 17 5. 18 

0.1 6. 17 6. 17 

0.1 7. 16 7. 17 

0.1 8. 17 8. 16 

0.0 9. 16 9. 16 

0.1 10. 17 10. 16 

0.1 

Time: 13:00 to 14:00 PST 

Temperature 

HMP45C Logger 

SN: D3250873 

l. 9.1 

2. 9.2 

3. 9.3 

4. 9.3 

5. 9.3 

6. 9.5 

7. 9.5 

8. 9.5 

9. 9.4 

10. 9.5 

Average Difference 

Difference =Site ~ Measured 

Diff 

-2 

-2 

-1 

-1 

-1 

0 

-1 

0 

1 

Barometric Pressure - Co-Located Calibration 

Time: 13:00 PST 

Barometric Pressure 

Logger Reading 

mmHg 

SN:D31400332 

1. 639.2 

2 639.3 

3. 639.3 

4. 639.4 

Average Difference 

"'Difference =Site - Measured 

Measured 

VWR Thermo Hygro 

SN- 80357103 

l. 9.0 

2. 9.0 

3. 9.2 

4. 9.2 

5. 9.3 

6. 9.4 

7. 9.4 

8. 9.4 

9. 9.4 

10. 9.4 

Measured 

Brunton Altimeter Diff • 

mmHg 

SN:NA 

1. 638 1.2 

2. 638 1.3 

3. 639 0.3 

4. 639 0.4 

I 0.81 

Copy of 235-3-12162009CALAQ-MET 2 

1 

-0.6 
,\ II ~ ~( II " I' I ' C. 

Calibration Form 

Marigold Air Quality and Meteorological Monitoring 

HeN Sampler System 

Time: 13:00 to 14:00 PST Temp rC) 

Inches Digital Flow (l/min) low 

mV Pressure Transducer Raw Inches Sampler Manometer Flow BIOS Pl/Pa Qa (Flow Meter) 

SN' 35543F3 SN'35542F3 SN' 35545F3 SN' 35583F3 

l. l. 59,10 l. 56.50 l. 2.001 1. 0.8271 1. 0.11906 

2. 2. 52.10 2. 50.20 2. 1.84 2. 0.848 2. 0.10953 

3. 3. 47.71 3. 45.70 3. 1.72 3. 0.861 3. 0.10239 

4. 4. 42.78 4. 41.60 4. 1.60 4. 0.875 4. 0.09524 

5. 5. 37.84 5. 36.20 5. 1.42 5. 0.889 5. 0.08453 

6. 6. 34.38 6. 32.90 6. 1.35 6. 0.900 6. 0.08036 

7. 7. 7. 7. 7. 7. 

8. 8. 8. 8. 8. 8. 

9. 9. 9. 9. 9. 9. 

10. 10. 10. 10. 10. 10. 

I #DIV/OI I 45.6517 I 43.85 I 1.655 

"'O ifference :;; Site - Measured 

' Difference = ((Site - Measured)/Measured)*100 

Slope Intercept 

-1.8120 1.0451 

Correlation 

-0.9974 

Tube 1 Flow Tube 2 Flow Tube 3 Flow 

Notes for next trip: 

;8 Iv ~ 12/ 16/2009 

Si~ature Date: 

235-3-12162009CALAQ-MET 3 
APPENDIX D 

Hydrogen Cyanide (HCN) Fence Line Monitoring Plans 

Site-Specific Hydrogen 

Cyanide (HCN) 

Perimeter Monitoring 

Plan 

MARIGOLD MINING COMPANY

PROJECT 235-2-2 

OCTOBER 2009 
 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 ......................................................................................................................... 5

3.1 Operations Boundary and Nearest Population Areas ............................................................................................. 5

3.2 Potential Sources of HCN ....................................................................................................................................... 5

3.2.1 Leach Pads ..................................................................................................................................................... 5

3.2.2 Refinery ........................................................................................................................................................... 5

3.3 Proposed HCN Monitor Location ............................................................................................................................ 5

4 PROPOSED MODIFICATIONS TO THE GENERAL HCN MONITORING PLAN ....................................................... 10

Figures 

Figure 2.1: Calendar Year 2008 Wind Rose .................................................................................................................... 2

Figure 2.2: First Quarter 2008 Wind Rose ....................................................................................................................... 3

Figure 2.3: Second Quarter 2008 Wind Rose .................................................................................................................. 3

Figure 2.4: Third Quarter 2008 Wind Rose ...................................................................................................................... 4

Figure 2.5: Fourth Quarter 2008 Wind Rose .................................................................................................................... 4

Figure 3.1: Proposed HCN Monitoring Site ...................................................................................................................... 7

Figure 3.2: Large Scale Area Map ................................................................................................................................... 8

Figure 3.3: Refinery and Ponds ....................................................................................................................................... 9

Appendices 

Appendix A: General HCN Monitoring Plan 

 
 1 

SECTION 1 

INTRODUCTION 

1.1 Mine Description and Proposed Monitoring 

Marigold Mining Company (Marigold) operates a gold mining facility located approximately 

four miles south of Interstate 80 at the Valmy Interchange (Exit 216), in Humboldt County, 

Nevada. The Marigold facility consists of open-pit mining and gold recovery processes including 

heap leaching, carbon adsorption, stripping and regeneration, electrowinning, retoring, and 

refining. 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, Marigold plans to install and operate 

an HCN monitor downwind of the potential HCN sources, at the boundary of the project 

operations at the Marigold mine. 

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 A. 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 Marigold. 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. The site location also takes into consideration accessibility for the 

Marigold maintenance and project technicians. 

The following sections describe the predominant wind direction, the Marigold project boundary, 

the nearest population areas to this boundary, the potential sources of HCN emissions and their 

locations at Marigold, and the proposed HCN monitoring site. 

The HCN monitoring system proposed herein is a new system. Typically, a full field test and 

system verification of such a prototype monitor would be scheduled in advance of deploying the 

monitor for data collection. This is done in order to identify system design problems, and refine 

the system configuration and operating and maintenance procedures as appropriate. Due to the 

schedule that EPA has requested, only limited field testing and system verification will be 

possible prior to data collection. Because of this, it is possible that problems may arise with the 

monitoring system which will affect data collection and/or validity; however, Marigold will take 

all reasonable measures to avoid such problems in an effort to minimize any disruptions to the 

monitoring program. 
 2 

SECTION 2 

METEOROLOGY 

2.1 Prevailing Wind Direction 

Marigold currently operates a meteorological station. This station is located at 488,951 meters 

east, 4,511,675 meters north, UTM Zone 11N, NAD83, elevation 4,669 feet, approximately one 

mile northeast of the refinery. Figure 2.1 summarizes the hourly wind directions (the direction 

from which the wind is blowing) and wind speeds for the 2008 calendar year. Figures 2.2 

through 2.5 provide wind roses for each calendar quarter of 2008. As shown by the annual and 

quarterly wind roses, the prevailing winds are from the west-northwest to southwest, with the 

most predominant annual wind direction from the west-southwest. 

Figure 2.1: Calendar Year 2008 Wind Rose 

 
 3 

Figure 2.2: First Quarter 2008 Wind Rose 

Figure 2.3: Second Quarter 2008 Wind Rose 

 
 4 

Figure 2.4: Third Quarter 2008 Wind Rose 

Figure 2.5: Fourth Quarter 2008 Wind Rose 

 
 5 

SECTION 3 

PROPOSED HCN MONITORING SITE 

3.1 Operations Boundary and Nearest Population Areas 

Aerial photos and shaded relief maps are provided in Figures 3.1 through 3.3. Figure 3.1 

provides an aerial photo of the mine site, the project boundary, and the potential HCN sources. 

Figure 3.2 provides a shaded relief map of the area surrounding the Marigold mine. The nearest 

residents are in the small town of Valmy located three miles north of the mine site, and in the 

town of Battle Mountain located twelve miles southeast of the mine site. Interstate 80 also passes 

approximately three miles northeast of the mine site. 

3.2 Potential Sources of HCN 

Figures 3.1 and 3.3 highlight the potential sources of HCN emissions at Marigold. These sources 

include a leach pad, pregnant and barren ponds, tanks containing cyanide solution, and a single 

stack for the electrowinning cells and pregnant and barren tanks at the refinery. A closer view of 

the HCN sources at the refinery and pond area is shown in Figure 3.3. 

3.2.1 Leach Pads 

Marigold operates one active leach pad. Cyanide leach solution is applied to portions of the pad 

primarily via drip emitters. Potential HCN emissions come from the cyanide solution applied to 

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. Carbon-in-Column (CIC) tanks used to adsorb gold 

from the pregnant solution are also potential HCN sources. The CIC tanks are located just north 

of the pregnant and barren ponds. The pad, ponds, and tanks are shown in Figures 3.1 and 3.3. 

3.2.2 Refinery 

The refinery area, shown in Figure 3.3, contains a single stack for the electrowinning cells and 

pregnant and barren tanks. The electrowinning cells and pregnant and barren tanks process 

aqueous cyanide solutions, which have the potential for HCN emissions. All of these units are 

within the refinery building, and the exhaust from these units is ducted through a carbon 

adsorption bed before being released to the atmosphere. 

3.3 Proposed HCN Monitor Location 

Marigold proposes to place the HCN monitor northeast of the potential HCN sources 

approximately one mile from the refinery and 1.3 miles from the edge of the leach pad, at the 

existing meteorological station. As shown in Figure 3.1, this location is in a favorable position to 

detect emissions from the potential HCN sources due to winds from the west-southwest to the 

south-southwest. These wind directions account for 32 percent of the hourly winds, as shown by 

Figure 2.1. In addition, winds from the southwest quadrant blow directly towards Interstate 80. 
 6 

In the fourth quarter, when the monitoring will occur, the most predominant wind direction is 

the southwest. 

The proposed monitor location has line power and can be reached via a road maintained by 

Marigold. The proposed site coordinates are 488,951 meters east, 4,511,675 meters north, UTM 

Zone 11N, NAD83, elevation 4,669 feet. 

 
7
8
9
 10 

SECTION 4 

PROPOSED MODIFICATIONS TO THE GENERAL HCN 

MONITORING PLAN 

Marigold does not propose any modifications to the General HCN Monitoring Plan with regards 

to the HCN sampling equipment. Marigold does, however, propose to use its existing 

meteorological station to collect the meteorological parameters (with the exception of relative 

humidity) outlined in the General HCN Monitoring Plan in lieu of installing the meteorological 

measurement equipment described in the general plan. 

The existing station is located at the proposed HCN monitor site and, therefore, it will provide 

representative data for the overall mine and the monitor site. See Figure 3.1. The sensors for 

wind direction, wind speed, ambient temperature, and barometric pressure at the existing 

meteorological station meet the data quality objectives and criteria described in Section 2.1 of the 

General HCN Monitoring Plan. Because the existing station is not equipped to measure relative 

humidity, this sensor will be installed at the HCN monitor site per the General HCN Monitoring 

Plan. The existing station is also audited on a quarterly basis. 

As discussed in Section 3.3, line power is available at the proposed HCN monitor location. 

Therefore, the solar power system described in the General HCN Monitoring Plan will not be 

needed. 
APPENDIX A 

General HCN 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