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

Identification of Potential EnvironmentalEffects and Proposed Mitigation• ANFO use and storage (release of nitrogen compounds to surface waters)• Runoff from waste rock piles, stockpiles, roads (ANFO residues, high metals, TSS)• Lake dewatering (high TSS water once partially dewatered)• Runoff or fugitive dust from concentrate storage and handling (high metals)• Fuel transport and handling (hydrocarbons)• In-stream construction of dams, culverts, bridges (TSS, other)• Discharge or leaking from Tailings Management Facility (poor quality water)• Disposal of treated sewage effluent and/or sludge (nutrients)• Disposal of open pit and underground sump water (ANFO residues, metals, salts)Dust-generating activities include the construction of roads, the airstrip, dams, buildings, and theongoing use of roads and the airstrip. These activities can introduce particulate material (such asTSS, aluminium, other metals associated with rock material being used) into surrounding surfacewaters. The use of ANFO (ammonium nitrate fuel oil) as an explosive to break apart rock alsocan leave nitrogen residues on rock, which is easily dissolved in water and introduced tosurrounding surface waters. High concentrations of nitrate, nitrite, and ammonia can all be toxicto aquatic life, but can be limiting to aquatic life at extremely low concentrations.The storage and use of ANFO can result in the introduction of high concentrations of nitrogencompounds to surface waters.Runoff from waste rock pile, ore stockpiles, and roads could be of poor quality. Water could beacidic, neutral, or alkaline, and contain high metals and high levels of nitrogen compounds.Camp Lake will have to be dewatered in order to mine the Main Zone. The initial portion of lakewater to be dewatered will reflect the natural quality of Camp Lake water. However, once thewater level drops to a certain level, suspension and erosion of exposed and near-surface lakesediments will cause the TSS levels to increase to unacceptable levels for discharge into naturalwaters. This water will then have to be treated or stored in some manner.Concentrate is the end product of the mine, and will contain high metal concentrations. Fugitivedust from storing or handling the concentrate could introduce metals into surrounding surfacewaters.Fuel handling and use on site could potentially cause the introduction of hydrocarbons to surfacewaters.The in-stream construction of dams, bridges, and culverts could potentially disturb lake andstream sediments, and cause high TSS (and possibly high total phosphorus and metals) to beintroduced to surface waters.January 2008 Hackett River Project – Project Proposal Sabina Silver CorporationReport Version B.1 7–10 Rescan Environmental Services Ltd. (Proj. #833-2)