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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.
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