080121-08MN006-Sabina Hackett River Project Proposal ... - NIRB

Identification of Potential EnvironmentalEffects and Proposed Mitigationduring the operation of the mine. Water will be reclaimed from the facility and used in the mill.Dams will be constructed with impermeable liners. The facility will be operated with sufficientwater cover to minimize oxidation and re-entrainment of tailings solids. Future studies will beable to predict the potential water quality in the impoundment facility, and a closure plan will bebased on the predicted water quality for the facility.7.3.1.7 Freshwater Sediment QualityPotential EffectsPotential project-related impacts to sediment quality include:• Construction activities, and runoff of TSS (introduction of additional particulate materialto sediments)• fugitive dust from concentrate storage and handling (possibly settle and end up insediments; elevated metals)• Fuel transport and handling (hydrocarbons)• In-stream construction of dams, culverts, bridges (disturb and mix up sediments)• Discharge or leaking from Tailings Management Facility (could have suspended materialthat would settle into sediments)• Disposal of treated sewage effluent and/or sludge (nutrients)Construction activities can generate dust, and as with affecting surface water quality, sedimentquality could be affected by the deposition of particulate material onto stream or lake sediments.Fugitive dust from concentrate would be high in metals, and this material could settle onto thesediments of lakes and streams if it were introduced into surface waters.Fuel handling could introduce hydrocarbons into lake or stream sediments if there was a spill orif not handled properly.In-stream construction activities could disturb and suspend lake and river sediments, causingtheir transport downstream or to other locations.The TMF will contain the solid fraction of the tailings. If allowed to escape, these tailings wouldalter natural lake and stream sediments, and affect metal concentrations as well as nutrientconcentrations (from sewage effluent) in existing sediments.Proposed MitigationDust generation from the use of roads and the airstrip, and fugitive dust from concentratehandling, will be mitigated to minimize the effects on surface water quality and sediment qualityas described in the surface water quality section above.Fuel storage and handling areas will be lined and bunded to contain any hydrocarbon leakage.January 2008 Hackett River Project – Project Proposal Sabina Silver CorporationReport Version B.1 7–12 Rescan Environmental Services Ltd. (Proj. #833-2)