2006

MEADOWBANK GOLD PROJECT

Cumberland Resources Ltd.

AIR QUALITY EIS

2006

Identify activities potentially impacting air quality Define type of air contaminants Calculate emissions and find their locatons Predict ground-level concentrations Compare predicted concentrations to AAQO

MEADOWBANK GOLD PROJECTMEADOWBANK GOLD PROJECT

Scope Scope Air Quality Overview

2006Point Emission Sources

Power plant- 15.5 MW maximum power demand- three diesel generators plus one stand-by- atmospheric dispersion maintained by 30.5 m stacks

Primary crusher and mills

2006Mobile Emission Sources

Most of mobile sources will be trucks Ore payload 90 tonnes, empty truck 60 tonnes Maximum haul distance 7.5 km one way Diesel supply for mobile equipment 11,200 m3/a

2006Fugitive Emission Sources

Tailings Coarse-ore stockpile – 17 m high 44 m base diameter Conveyors Drilling and blasting

2006Air Pollutants

Sulphur oxides (SO2 and SO3) – sources:

- diesel engines (power plant, trucks, loaders, tractors) Nitrogen oxides (NO and NO2) – sources:

- as above Particulate matter (TSP, PM10, PM2.5) – sources:

- diesel engines, wheel entrainment, fugitive Other contaminants:

- carbon monoxide and carbon dioxide- unburned hydrocarbons

2006Dispersion Modelling

Dispersion modelling predicts ambient ground-level concentration of air pollutants

Model inputs:- emissions data (rate, location, source parameters)- meteorology, buildings, receptors data

Models outputs:- concentration isopleths- PM precipitation isopleths

2006Summary of Dispersion Modelling Results

Substance Sources Average TimeMax GLC

μg/m3

AAQSμg/m3

Sulphur dioxide (SO2) Plant & Vehicles1 h

24 hAnnual

134241.7

45015030

 

Nitrogen oxides (as NO2) Plant & Vehicles1 h

24 hAnnual

3621149.5

40020060

 

Carbon monoxide (CO) Plant & Vehicles1 h8 h

2123624

35,00015,000

 

Particulate matter <10 μm dia. (PM10) Plant24 h

Annual110.9

50---

 

2006Monitoring

Monitoring of the concentration of suspended particulate matter in the air surrounding the major areas of activity (dynamic monitoring) with Partisol air samplers.

2006Monitoring

Monitoring of the deposition rate of particles (static monitoring).

2006Mitigation Processing Plant The diesel power plant engines with low NOx emissions to prevent ozone formation and

with low hydrocarbon emissions to lower greenhouse gas (GHG) emissions Install dust filters at the primary crusher building and at fine grinding facilities (SAG mill

and ball mill) and provide dust suppression equipment (dust covers, sonic sprays, etc.) Install enclosure of feed conveyor to avoid fugitive emissions during windy weather Transportation Impose vehicle speed limit on Vault haul road to mitigate fugitive dust and reduce

engine emissions Apply dust suppressants (water, calcium chloride) to haul and service roads during dry

weather to mitigate fugitive dust Blasting & Waste Disposal Limit blasting to calm days or use delay blasting technique; natural mitigation to take

place when mining pits are from 85 to 175 m below the ground level; Cover dewatered tailings with non-potentially acid-generating (non-PAG) aggregates to

control wind erosion. Miscellaneous Items Use site-generated mineral material (dirt, aggregate, etc.) to cover disposed solid waste

at the waste dump Apply vegetation cover on stripped areas and long-term stockpiles.

2006Summary

Main air pollutants will include SO2, NOx and particulate matter No hazardous pollutants will enter the atmosphere Concentrations will comply with AAQO Higher PM concentrations can be expected near hauling trucks and

areas of mineral material discharges Concentration of PM will be monitored Mitigation methods will be implemented to keep low concentration of air

pollutants