1 

M E M O R A N D U M

To: Nevada Division of Environmental Protection, Bureau of Air Quality 

From: Air Quality Subcommittee of the Nevada Mining Association 

Date: July 16, 1996 

Subject: Recommended Methodology for Quantification of Fugitive Dust Metals Emissions 

from Mining Activities for Title V Applicability 

The Air Quality Subcommittee of the Nevada Mining Association (NMA), in response to the 

Nevada Division of Environmental Protection=s (NDEP) letter of April 24, 1996, has developed a 

recommended procedure for estimating fugitive dust metals emissions from mining activities. The 

metals of interest are those listed as a Hazardous Air Pollutant (HAP) in Section 112(b) of the Clean 

Air Act. Part of this development process included identification of specific operations at a typical 

precious metals mining facility that would produce fugitive particulate emissions and, consequently, 

fugitive dust metals emissions. The objective of developing a specific procedure for emissions 

estimation is to provide a standardized practical approach for Nevada precious metals mining 

facilities to use in assessing whether their facility is a major Title V source on the basis of HAP 

emissions. 

The emission factors and emissions estimation procedures presented in this memorandum represent 

what the Subcommittee believes to be the most appropriate for purposes of estimating fugitive dust 

and metals emissions for assessing Title V applicability. While several different emission factors 

exist for each mining activity described which, in turn, provide a wide range of emission estimates, 

we believe the approach presented herein provides the most realistic and consistent method for 

emissions estimation. 

Identification of Mining Activities Generating Fugitive Dust

Operations at several Nevada precious metals mines were evaluated to determine the primary types 

of mining activities that typically generate fugitive dust emissions. Other secondary activities occur 

within a typical precious metals mining operation that potentially generate fugitive dust emissions 

such as pick-up truck and employee vehicle traffic and the intermittent use of heavy equipment for 

short-term construction and maintenance tasks. However, total fugitive dust emissions potentially 

originating from these activities are small compared to those emissions attributable to mining 

activities that are integral to the operation of a mining facility. Thus, only the primary mining 

activities are considered in detail in this quantification evaluation. 

The primary mining activities are grouped under the following categories, and discussed below: 
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C Pit Operations 

C Ore and Waste Rock Haul 

C Haul Road Repairs/Maintenance 

C Wind Erosion 

Pit Operations

These operations include the initial removal of ore and surrounding waste rock from the pit by 

drilling and blasting and transfer of the blasted ore/waste rock material from the pit to haul trucks 

which transport the material to its next destination (i.e., crusher, leach pads, stockpiles, etc.). The 

first two pit operations specified are drilling and blasting. The remaining pit operations are 

handling of the blasted material by front end loaders and/or bulldozers to enable its transfer to haul 

trucks for transport to its next destination. 

Ore and Waste Rock Haul

Once the ore/waste rock material has been removed from the pit, the ore and waste rock are typically 

separated and transferred to haul trucks for haulage to their specific destinations (i.e., haul routes). 

Fugitive particulate emissions generated during this process are associated with the contact of the 

haul truck tires with the haul road surface. Total emissions are significantly affected by the length of 

the haul routes, the number of trips required to transport the material, the silt and moisture content of 

the roadbed material and the control practices used on the haul road surface. Once the ore or waste 

rock reaches its next destination (i.e., primary crusher, waste rock stockpile, leach pad, etc.), the haul 

truck is then unloaded, generating fugitive dust emissions. Thus, activities associated with ore and 

waste rock haul consist of sets of haul road travel and material transfer (unloading) operations. Each 

set corresponds to a distinct haul route. Controls for haul road emissions typically consist of the 

periodic application of water and, sometimes, a combination of water and chemical dust 

suppressants. Water sprays and/or enclosure are the most typical control practices utilized for truck 

unloading. 

Haul Road Repairs/Maintenance

To maintain proper safety conditions for haul truck travel, graders are used to level the haul road 

surface. To minimize fugitive dust emissions, water trucks are used to periodically moisten the haul 

road surface. Thus, grader maintenance and water truck travel on the haul roads are the two primary 

operations typically occurring at a Nevada precious metals mining facility, associated with haul road 

repairs and maintenance. The same control practices used for minimizing fugitive dust emissions 

from haul truck travel also apply to haul road repairs and maintenance activities. 
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Wind Erosion

Various ore surge piles and stockpiles, waste rock dumps and stockpiles and tailings impoundments 

exist at a typical precious metals mining facility. Storage areas such as ore surge piles and 

stockpiles are frequently disturbed to transfer ore to the processing facilities. This frequent 

disturbance does not allow the surface of the ore storage area to become crusted, allowing wind 

erosion to occur in the presence of sufficiently strong winds. Thus, these storage areas can be 

considered active disturbance areas. 

However, deposition of waste rock on dumps and stockpiles only occurs over a small proportion of 

the total storage area at any given time. Since the waste rock on the remaining portions of the 

storage area remains relatively undisturbed (i.e., not used as part of the mineral extraction process 

once deposited on the storage area) in between periods of higher wind speeds and are allowed to 

form a crust, these storage areas are essentially inactive areas. 

Tailings differ significantly from the ore and waste rock in silt and moisture content. Thus, the wind 

erosion potential of tailings impoundments differ from either the actively disturbed ore storage areas 

or the relatively inactive waste rock storage areas. The ore storage areas, the waste rock storage 

areas and the tailings impoundments exhibit three distinctly different potentials for particulate 

emissions from wind erosion. The use of controls such as water and chemical dust suppressants are 

more effective for relatively inactive disturbance storage areas and, consequently, are used less 

frequently on actively disturbed areas. 

Recommended Particulate Emission Factors for Mining Activities

Various particulate emission factors for the identified mining activities were evaluated for 

appropriateness and reasonability of resultant emission estimates. On the basis of this evaluation, a 

set of particulate emission factors presented in a memorandum authored by the Wyoming 

Department of Environmental Quality, Air Quality Division (WDEQ/AQD), dated January 24, 1979 

is recommended as the factors providing the most realistic estimates of fugitive particulate emissions 

from large surface mining operations. This emission factor set has been used successfully by the 

WDEQ/AQD for nearly 20 years in managing air resources within the Powder River Basin where 

several very large surface coal mines operate in close proximity. This emission factor set has also 

been accepted on a case-by-case basis by the reviewing agencies in Colorado, New Mexico, Alaska 

and Arizona for modeling/permit applications for mining sources. The WDEQ/AQD emission factor 

set is recommended to be used with specific control practices on mining activities that are consistent 

with those implemented in other states such as Nevada, Wyoming, Colorado, New Mexico, Alaska 

and Arizona. 

The Powder River Basin Model Validation Analysis, prepared by TRC for the WDEQ/AQD and 

dated August 2, 1991, demonstrated, by comparing modeled to monitored total suspended particulate 

(TSP) values around the large surface coal mines, that the use of these factors with the Fugitive Dust 

Model (FDM) or the Industrial Source Complex (ISC) model provides more accurate estimates of 

ambient concentrations than the use of emission factors strictly from AP-42. Over predictions of 
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modeled concentrations versus monitored concentrations are significantly reduced by using the 

WDEQ/AQD factors. The validation study concluded that the ratios of annual-averaged modeled 

concentrations (using the short-term version of ISC) to corresponding monitored concentrations 

ranged from 0.78 to 1.23 when using the WDEQ/AQD factors for the suite of 22 monitoring 

locations considered in the study. The average ratio of predicted, maximum modeled to 

corresponding monitored concentrations for 24-hour averaging periods was 2.5 when using ISC with 

the WDEQ/AQD emission factor set. Use of strictly AP-42 factors would result in significantly 

higher modeling to monitoring concentration ratios than those identified above. These higher ratios 

would result because the general haul road emission factors found in Section 13.2.2 of AP-42, 

Miscellaneous Source - Unpaved Roads, are approximately one order of magnitude larger than the 

WDEQ/AQD haul road emission factors (assuming equal control efficiencies are applied). Since 

haul road emissions are a significant portion of total fugitive dust emissions from mining activities, 

use of the AP-42 factors would result in estimated modeling to monitored concentration ratios 

approaching one order of magnitude higher than those estimated from the WDEQ/AQD emission 

factor set. 

Further, nearly 20 years of sampling at a large number of ambient particulate sampler sites within 

the Powder River Basin have demonstrated that standards are not being threatened, validating earlier 

modeling for permit application analyses using WDEQ/AQD factors; however, the use of AP-42 

factors in these same modeling analyses would have suggested large numbers of exceedances. We 

suggest that the NDEP contact Mr. Bernie Dailey at the WDEQ/AQD [(307) 777-7391] should you 

have concerns regarding the use of these factors. 

WDEQ/AQD emission factors for each identified mining activity are presented in the following 

activity-by-activity description. For certain mining activities which do not have WDEQ/AQD 

emission factors, the most appropriate AP-42 emission factor is specified. To maintain consistency 

with using the WDEQ/AQD emission factor approach, control efficiencies attributable to watering 

and chemical dust suppressants are simplified by assigning a control efficiency of 50% to water 

alone and a control efficiency of 60% for using water combined with chemical dust suppressants or 

chemical dust suppressants alone. Except for specifically identified mining activities, the 

WDEQ/AQD emission factor for PM10 is the TSP emission factor, multiplied by 0.30. 

1. Drilling

The WDEQ/AQD does not have specific emission factors for drilling. The emission factor proposed 

herein as the most appropriate for estimating drilling emissions is from Table 11.19.2-2 of AP-42 for 

wet drilling of unfragmented stone from crushed stone processing operations. This factor is chosen 

over other candidate factors such as Table 11.9-4 for drilling of overburden at a western surface coal 

mines since the ore/waste rock material being drilled is more similar to unfragmented stone than 

overburden and some control for the initially moister condition of the ore/waste rock material during 

the drilling procedure is considered. Thus, the PM10 emission factor (EF) is: 

EFPM10 = 0.00008 lb/ton 

EFTSP = 0.000168 lb/ton 
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No specific EF for TSP is given; however, the footnote to Table 11.19.2-2 states that a ratio of 2.1 

should be multiplied by the PM10 emission factor to derive corresponding TSP, consistent with the 

relative ratios found in Sections 13.2.2 and 13.2.4 of AP-42. 

2. Blasting

The WDEQ/AQD memorandum of 1/24/79 presents emission factors of 50 and 35 lb/blast for 

blasting of overburden and coal, respectively. A multiplier of 0.75 to account for the proportion of 

particulate matter greater than 30 microns in diameter, settling out prior to reaching off-site ambient 

air exposure locations, is also given; however, to provide for a more conservative estimate of total 

suspended particulate matter, the multiplicative factor of 0.75 is not used. Since the ore/waste rock 

material being blasted is more like overburden than coal, the TSP emission factor for overburden is 

used. Therefore, the TSP emission factor is: 

EFTSP = 50.00 lb/blast 

3. In-pit Handling and Transfer of Ore/Waste Rock to Haul Trucks

The WDEQ/AQD memorandum of 1/24/79 presents an overburden removal emission factor of 0.02 

lb/ton x 0.75 for truck/shovel operations. This emission factor includes both the handling of the 

ore/waste rock material after it has been blasted and the actual transfer of the material into haul 

trucks for transport to its next destination (i.e., primary crusher, waste rock dump, leach pad, etc.). 

Thus, this one calculation accounts for particulate emissions from handling and transfer of all 

materials leaving the pit and being hauled to their various destinations within the facility. The 

amount of fugitive dust generated from truck/shovel operations are assumed to be similar to frontend loaders or bulldozers performing the same functions. Again, the multiplicative factor of 0.75 is 

not used to provide a more conservative estimate of TSP emissions. The TSP emission factor is: 

EFTSP = 0.02 lb/ton 

4. Hauling of Ore and/or Waste Rock

The WDEQ/AQD memorandum of 1/24/79 presents the following haul road emission factor 

equation for TSP: 

EFTSP = 0.81s (S/30)n

 [(365-w)/365] T x 0.62, in lb/VMT 

where: 

s = silt content of roadbed material, in percent 

S = average vehicle speed, in mph 

n = 1 if S > 30; 2 if S < 30 

w = no. days per year with precipitation > 0.01" 

T = tire correction factor, 2.5 for large haul trucks 
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To use this equation to estimate annual TSP emissions, the total annual vehicle-miles for each haul 

route is calculated by dividing the amount of material hauled (in tons) by the average carrying 

capacity of a haul truck (in tons) and then multiplying by the round-trip distance (in miles) of each 

haul trip. 

5. Primary Crusher Truck Dump

The transfer of ore from haul trucks to the primary crusher truck dump is distinguished from other 

transfer operations (i.e., transfer to stockpiles, between conveyors, etc.) because of its significant 

drop height. The WDEQ/AQD emission factor presented in the 1/24/79 memorandum for product 

dumping (only coal and uranium are cited in the memo) for TSP is: 

EFTSP = 0.017 lb/ton 

6. Other Material Transfer Operations

The transfer of ore and/or waste rock from the haul trucks to various stockpiles, dumps, surge piles 

and leach pads does not have an applicable emission factor in the WDEQ/AQD memorandum of 

1/24/79. The appropriate emission factor equation selected for this operation is presented in 

Equation No. 1 of Section 13.2.4.3 of AP-42 for transfer of aggregate materials. This equation has 

already been used in previous permit application analyses for Nevada precious metals mining 

applicants. This emission factor equation for TSP is: 

EFPM = k (0.0032) (U/5)1.3 / (M/2)1.4, in lb/ton 

where: 

k = 0.74 for TSP; 0.35 for PM10

U = average wind speed, in mph 

M = material moisture content (%) 

7. Haul Road Repairs/Maintenance (Graders and Water Trucks)

Fugitive particulate emissions from the repair of haul roads by graders to maintain haul truck travel 

safety are estimated by the following emission factor equation, from the WDEQ/AQD memorandum 

of 1/24/79, for TSP: 

EFTSP = 32.00 x [(365-w)/365], in lb/hr 

where: 

w = no. of days per year with precipitation > 0.01" 

Typically, a control efficiency of 50% for watering is applied to the estimates of fugitive dust 

emissions from grader operations. The annual particulate emissions are estimated by multiplying the 

above value, in lb/hr per grader, by the total number of grader-hours of operation for the year. 
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Fugitive particulate emissions from water truck travel on the haul roads are based on the same haul 

road EF equation presented for the hauling of ore and/or waste rock. The tire correction factor is 

assumed to be 2.5, the same as for haul trucks, and the average speed of the water trucks is input for 

the variable, S. 

8. Wind Erosion

Emission factor equations for estimating fugitive dust from wind erosion of active disturbance areas, 

inactive disturbance areas and tailings impoundments are selected not only for appropriateness, but 

also in consideration of easily obtaining input information required for the emissions estimation. As 

a result, the following three emission factor equations are selected. 

8a. Wind Erosion from Active Disturbance Areas 

The WDEQ/AQD memorandum of 1/24/79 present emission factors that are representative of 

relatively inactive disturbance areas. AP-42 was reviewed for wind erosion algorithms appropriate 

for actively disturbed areas. Section 13.2.5 of AP-42 contains a procedure that considers frequency 

of wind speeds exceeding certain thresholds necessary to disturb specific types of surfaces. The 

meteorological data required for this procedure consists of at least hourly wind speed records, with 

the instantaneously highest wind speed occurring during that hour, collected at a site representative 

of the facility being evaluated. In addition, information either from on-site testing or from review of 

studies at reasonably similar facilities must be obtained concerning the erodibility potential of a 

specific type of surface (i.e., crusted, fine material, coarse material, dry, moist, etc.). Most Nevada 

precious metals mining facilities do not have access to such data and would have to expend 

significant time and expense to gather the necessary information. A simpler emission factor 

equation, as found in previous (i.e., Fourth Edition) versions of AP-42 is selected which has been 

used widely accepted in numerous emission analyses for regulatory purposes. Specifically, this 

equation is from Section 11.2.3.3 of the Fourth Edition of AP-42, as follows: 

EFPM = k (1.7)(s/5) [(365-w)/235] (f/15), in lb/day-acre 

where: 

k = 0.8 for TSP; 0.36 for PM10

s = silt content of surface material, in percent 

w = no. of days per year with precipitation > 0.01" 

f = proportion of annual hourly wind speeds > 12 mph, in percent 

8b. Wind Erosion from Inactive Disturbance Areas 

The WDEQ/AQD memorandum of 1/24/79 contains wind erosion emission factor equations for 

short-term and long-term fugitive dust emissions that are not commonly used for recent permit 

application analyses in Wyoming. The TSP emission factor currently utilized by the WDEQ/AQD 

for relatively inactive surface disturbance areas is: 
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EF(TSP) = 0.25 tons/acre-yr 

8c. Wind Erosion from Tailings Impoundments 

The WDEQ/AQD memorandum of 1/24/79 and AP-42 do not contain emission factors specifically 

appropriate for the unique material characteristics of tailings impoundments. Consequently, 

emission factors empirically derived from field studies conducted by Midwest Research Institute for 

EPA in the document, Gap Filling PM10 Emission Factors for Selected Open Area Dust Sources 

(EPA, February, 1988) are used. Table 11 of Section 13.0 presents a summary of empirically 

derived PM10 emission factors from both controlled and uncontrolled coarse, dry tailings ponds 

surfaces. The two field tests conducted on an uncontrolled area provided emission factors of 0.0738 

grams/min-m2 and 0.0256 grams/min-m2. Averaging these two values results in a mean PM10

emission factor of 0.0497 or approximately 0.05 grams/min-m2. However, this emission factor 

applies during wind speeds in excess of 42 miles per hour or 19 meters per second (m/s). To obtain 

an annual Aaverage@ emission factor, this initial value must be divided by the average number of 

minutes occurring between each episode of wind speeds in excess of 19 m/s. If a typical value of 

1,000 minutes (i.e., once every 16 to 17 hours) between episodes is used, the annual Aaverage@

emission factors becomes 0.00005 grams/min-m2

. 

Converting this emission factor to more conventional units: 

EF(PM10) = 0.1172 tons/acre-yr 

No specific EF for TSP is given; however, adopting the same approach used to estimate TSP 

emissions from drilling, the PM10 emission factor is multiplied by 2.1 to derive corresponding TSP, 

consistent with the relative ratios found in Sections 13.2.2 and 13.2.4 of AP-42. Thus, the TSP 

emission factor is: 

EF(TSP) = 0.2461 tons/acre-yr 

Site-specific values for these emission factors can be estimated by using on-site meteorological data 

to determine the annual average duration between wind speed episodes in excess of 19 m/s. 

Metals Content Data for Estimating Fugitive Dust Metals Emissions

Once a comprehensive fugitive dust emissions inventory with reasonable estimates is compiled, the 

metals components of the TSP emissions are calculated by multiplying by appropriate metals content 

data. Considerations for selection of appropriate metals content data include not only 

representativeness of site conditions, but also the availability and accessibility of such information. 

In view of these considerations, three procedures for obtaining metals content data are 

recommended. These procedures are: 
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1. Use elemental metal analysis of whole rock samples previously performed for assaying 

purposes. This analysis can consist of one set of whole rock samples, but ideally would 

include a suite of locations over a period of time to represent overall site conditions. From a 

statistical standpoint, the geometric mean for each metal from this suite of whole rock 

samples would be used to better represent site conditions. The metals concentrations, 

expressed in dimensionless units such as parts per million (ppm), are multiplied by the 

annual TSP emission rate for each specified mining activity. 

2. If available, elemental metal analysis of rock samples separated into ore and waste rock 

categories would allow a better distinction of potential fugitive dust metals emissions from 

those mining activities associated with handling the ore and those associated with handling 

the waste rock. In particular, haul road emissions would be better represented by using 

metals content analysis for waste rock, rather than ore, since roadbed material is primarily 

waste rock. Again, using the geometric mean of a suite of ore and waste rock sample 

analyses would provide a better representation of site conditions. 

3. If available, laboratory analyses for metals content of exposed ambient particulate filters can 

be used to better represent ambient exposure. Special sampling protocols such as longer 

exposure times (i.e., greater than 24 hours) or higher flow rates may have to be implemented 

to provide metals mass capture that exceed laboratory detection limits using a typical 

laboratory analytical procedure such as ICAP (inductively coupled argon plasma emission 

spectroscopy). Otherwise, a more sensitive laboratory analytical technique would need to be 

used. If metals analyses are below laboratory detection limits, then the typical practice of 

using 2 of the detection limit to represent concentrations of these metals is recommended. 

This procedure is the third alternative described since most Nevada precious metals mining 

operations do not have such data readily available and would have to expend significant time 

and expenses to procure such information. 

Example of Fugitive Dust HAP Metals Emission Estimates from a Generic Gold Mine

Fugitive dust HAP metals emissions from a generic Nevada mining facility, named ABC Gold Mine, 

using the recommended emission factor equations and procedures are estimated and summarized 

below. The ABC Gold Mine is an example of a facility with total PTE (Potential-to-Emit) emissions 

of each criteria pollutant below the Title V major source threshold of 100 tpy. Potential fugitive dust 

HAP metals emissions are estimated to evaluate the likelihood that this mining facility would still 

become a Title V major source solely based on total fugitive HAP metals emissions. 

Operating statistics of the ABC Gold Mine, pertinent to the estimation of fugitive dust HAP metals 

emissions, are: 
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C Annual Ore Throughput: 8,000,000 tons per year 

C Annual Non-ore (Waste Rock) Throughput: 20,000,000 tons per year 

C Total Round-trip Haul Road Distance: 11.25 miles per trip 

C Average Moisture Content of Ore/Non-ore: 5 percent 

C Average Silt Content of Ore/Non-ore: 7.6 percent 

C Average Annual Wind Speed: 10 miles per hour 

C Number of Days per Year of Precipitation > 0.01 inch: 90 

C Carrying Capacity of Haul Trucks: 85 tons 

C Average Speed of Haul Trucks: 17 miles per hour 

C Control Practice(s) Used on Haul Roads: Water and chemical additive; 60% control 

C Total Erodible Surface Area for Wind Erosion: 313.45 acres 

ABC Gold Mine already has laboratory analyses of the metal content of a suite of rock samples, 

distinguished between ore and waste rock. To provide a better representation of metal content in ore 

and waste rock across the facility, the geometric mean of the analyzed sample concentrations of each 

HAP metal in the ore samples and in the waste rock samples are estimated and summarized in Table 

1. Since some mining activities involve both ore and waste rock materials, the geometric mean 

concentrations of the mixture of these two material types are also estimated. These HAP metals 

concentrations are multiplied by the estimated fugitive TSP emissions for each mining activity, 

using the Wyoming emission factor set, to provide corresponding fugitive HAP metal emission 

estimates. Table 2 is an overall summary of estimated fugitive dust HAP metals emissions from 

mining activities. As can be seen from Table 2, using the fugitive particulate emissions estimated 

from the recommended Wyoming emission factor set and HAP metals concentration data 

representative of overall site conditions produces HAP metals emission estimates that are 

considerably below the 10 and 25 tpy Title V major source thresholds for individual and total HAPs, 

respectively. This conclusion is consistent with the designation of the ABC Gold Mine as a Title V 

minor source on the basis of total PTE emissions of each criteria pollutant. 

 TABLE 2. SUMMARY OF FUGITIVE DUST HAP METALS EMISSIONS FROM ABC GOLD MINE OPERATIONS

Source PM10 TSP

Description (lb/hr) (tons/yr) (lb/hr) (tons/yr)

Drilling 0.34 1.12 0.71 2.35Blasting 15.00 2.67 50.00 8.90In-pit Material Handling & xfer of Ore/Waste 19.66 84.00 65.54 280.00Ore Haul from Pit to Primary Crusher 8.21 35.07 27.36 116.89Unloading Ore to Primary Crusher 2.39 10.20 7.96 34.00Haul from the Pit to the Low Grade Ore Stk. 1.13 4.82 3.76 16.07Unloading Low Grade Ore to the Stockpile 0.10 0.42 0.21 0.89Waste Rock Haul to Dump 28.69 122.58 95.64 408.58Unloading Waste Rock to Dump 1.69 7.23 3.58 15.28Loading of Crushed Ore for the Leach Pads 0.72 3.06 1.51 6.47Haul of Crushed Ore to the Leach Pads 5.80 24.77 19.33 82.56Unloading Crushed Ore on the Leach Pads 0.72 3.06 1.51 6.47Haul Road Repairs/Maintenance 12.08 50.12 40.28 167.08Wind Erosion (Ore/Waste/Tailings) 8.16 35.73 22.37 97.97Total fugitive emissions 104.68 384.84 339.76 1,243.50

Source Arsenic Beryllium Cadmium Cobalt Chromium Manganese Nickel Lead Antimony 

Description (tons/yr) (tons/yr) (tons/yr) (tons/yr) (tons/yr) (tons/yr) (tons/yr) (tons/yr) (tons/yr) 

Drilling 5.58E-04 M 3.06E-06 M 5.88E-06 M 1.93E-05 M 3.27E-04 M 5.69E-05 M 1.06E-04 M 1.16E-03 M 6.02E-04 Blasting 2.11E-03 M 1.16E-05 M 2.23E-05 M 7.30E-05 M 1.24E-03 M 2.15E-04 M 4.02E-04 M 4.38E-03 M 2.28E-03 In-pit Material Handling & xfer of Ore/Waste 6.64E-02 M 3.64E-04 M 7.00E-04 M 2.30E-03 M 3.89E-02 M 6.78E-03 M 1.27E-02 M 1.38E-01 M 7.17E-02 

Ore Haul from Pit to Primary Crusher 1.55E-02 W 1.75E-04 W 3.74E-04 W 9.82E-04 W 1.57E-02 W 3.44E-03 W 5.80E-03 W 2.68E-02 W 2.89E-02 Unloading Ore to Primary Crusher 1.02E-02 O 4.08E-05 O 7.82E-05 O 2.75E-04 O 4.78E-03 O 7.62E-04 O 1.48E-03 O 2.27E-02 O 8.83E-03 Haul from the Pit to the Low Grade Ore Stk. 2.13E-03 W 2.41E-05 W 5.14E-05 W 1.35E-04 W 2.16E-03 W 4.73E-04 W 7.97E-04 W 3.68E-03 W 3.97E-03 Unloading Low Grade Ore to the Stockpile 2.66E-04 O 1.07E-06 O 2.04E-06 O 7.20E-06 O 1.25E-04 O 1.99E-05 O 3.88E-05 O 5.94E-04 O 2.31E-04 Waste Rock Haul to Dump 5.41E-02 W 6.13E-04 W 1.31E-03 W 3.43E-03 W 5.50E-02 W 1.20E-02 W 2.03E-02 W 9.36E-02 W 1.01E-01 Unloading Waste Rock to Dump 2.02E-03 W 2.29E-05 W 4.89E-05 W 1.28E-04 W 2.06E-03 W 4.49E-04 W 7.58E-04 W 3.50E-03 W 3.77E-03 Loading of Crushed Ore for the Leach Pads 1.94E-03 O 7.76E-06 O 1.49E-05 O 5.24E-05 O 9.09E-04 O 1.45E-04 O 2.82E-04 O 4.32E-03 O 1.68E-03 Haul of Crushed Ore to the Leach Pads 1.09E-02 W 1.24E-04 W 2.64E-04 W 6.94E-04 W 1.11E-02 W 2.43E-03 W 4.10E-03 W 1.89E-02 W 2.04E-02 Unloading Crushed Ore on the Leach Pads 1.94E-03 O 7.76E-06 O 1.49E-05 O 5.24E-05 O 9.09E-04 O 1.45E-04 O 2.82E-04 O 4.32E-03 O 1.68E-03 Haul Road Repairs/Maintenance 2.21E-02 W 2.51E-04 W 5.35E-04 W 1.40E-03 W 2.25E-02 W 4.91E-03 W 8.29E-03 W 3.83E-02 W 4.13E-02 Wind Erosion (Ore/Waste/Tailings) 2.32E-02 M 1.27E-04 M 2.45E-04 M 8.03E-04 M 1.36E-02 M 2.37E-03 M 4.43E-03 M 4.82E-02 M 2.51E-02 Total fugitive emissions 0.21 0.00 0.00 0.01 0.17 0.03 0.06 0.41 0.31 O - Metal emissions based on TSP emission estimates; metal content is based on analyzed geometric mean of ore samplesW - Metal emissions based on TSP emission estimates; metal content is based on analyzed geometric mean of waste rock samplesM - Metal emissions based on TSP emission estimates; metal content is based on analyzed geometric mean of both ore and waste rock samples