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

Project Descriptionbeneath Camp Lake, and modify the design and operating conditions of the open pit to suit theexpected conditions.2.4.4.6 ExplosivesThe supply of explosives will be provided by a third party that would manufacture emulsionexplosives on site and deliver the product to the blast hole as required. Under normal operatingconditions, a limited amount of emulsion explosives would require storage on site at any onetime, with the main storage area being at the Port Site. Blasting accessories and miscellaneousexplosives products would be supplied via the port at Bathurst Inlet and stored on site inapproved facilities.2.4.5 Underground MiningThe preliminary study has employed underground mining methods for the extraction of the entireBoot Lake deposit as well as the lower portions of the East Cleaver and Main Zone depositsbelow the ultimate open pit limits. The prefeasibility study will also consider mining the BootLake deposit as a combined open pit and underground operation. The majority of theunderground mining functions will be performed by the mine operator using purchasedequipment, with the potential exception of specialist ongoing mining activities such as raisemining. The underground mine operations will be highly mechanised employing mobiletrackless mining equipment and ramp access to all mining levels within the mine.2.4.5.1 Mining MethodThe Boot Lake underground mine will potentially extend to a depth of 650 metres or more belowsurface, which is well below the 500 metre depth of permafrost that has been estimated in theBoot Lake area. As such, underground mining of the Boot Lake deposit will take place in bothfrozen and unfrozen ground. The potential underground operations on the East Cleaver and MainZone deposits is currently assumed to be within the permafrost zone, however additional work isplanned to confirm these ground conditions.The Boot Lake deposit is planned to be mined by underground methods in its entirely employingsublevel longhole stoping with both cemented and uncemented crushed rock backfill in thepermafrost zone, and cemented paste backfill in the unfrozen zone below. A suitable supply ofcrushed rock for backfill will be sourced from the surface waste storage facility, supplementedwith waste rock from ongoing underground development. The potential underground portions ofthe East Cleaver and Main Zone deposits are planned to be mined by the sub level cave methodwhich do not require backfill.The prefeasibility study will identify and evaluate other potential mining methods for all threepotential underground operations in order to develop an optimum plan for undergroundoperations. The mining methods to be reviewed will include an assessment of both caving andnon-caving mining methods, the requirement for backfill associated with each mining method, aswell as the productive capacity of each method. The type of backfill, if required, as well asbackfill material sources will also be reviewed as part of the prefeasibility study.January 2008 Hackett River Project – Project Proposal Sabina Silver CorporationReport Version B.1 2–14 Rescan Environmental Services Ltd. (Proj. #833-2)