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

Identification of Potential EnvironmentalEffects and Proposed MitigationFor esker areas that are disturbed, the area will be re-sloped to an angle consistent with the predisturbanceslope. Re-sloping will be carried out such that the slopes provide the same level ofescape terrain as prior to the disturbance. Slopes will not exceed 30%.Disturbed eskers can also be seeded to minimize erosion. Eskers can be seeded with a certifiedweed free native seed mix that has been found to be successful in this climate and region(Martens, 2007):• alpine bluegrass (Poa alpina): 40%;• tufted hairgrass (Deschampsia ceaspitosa): 40%; and• spike trisetum (Trisetum spicatum): 20%.The seed mix will be Canada No. 1 grade to minimize the potential of introducing unwantedplants.7.3.1.10 GeologyPotential EffectsPotential project-related impacts to geology include:• Removal of ore and other rock to develop the three deposits• Exposure of new rock to the surface, thereby changing the metal leaching potential of theareaThe removal of rock in order to develop the three deposits will permanently change the localgeology. Exposure of new rock could potentially affect the leaching of metals from host rockinto surface waters via sump water, waste rock pile runoff and tailings.Proposed MitigationThere is no mitigation possible for the permanent removal of rock from the development of thethree deposits.An ARD/ML program is underway that will help determine how to mitigate the effects of newlyexposed rock material in the form of ore, waste rock and tailings. Management Plans will bedeveloped for all of these materials based on results of the ARD/ML program and bestmanagement practices.Mitigation of the waste rock piles could potentially involve the use of liners at the base of thepiles, the construction of ditches and sediment ponds to capture runoff, and the covering of thewaste dumps with a designed cover if the material required is available in sufficient quantities.The mitigation of the pit walls may require benching and covering of the benches with adesigned cover to limit exposure of acid generating surfaces.January 2008 Hackett River Project – Project Proposal Sabina Silver CorporationReport Version B.1 7–14 Rescan Environmental Services Ltd. (Proj. #833-2)