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

Project DescriptionThe preliminary operating philosophy, including the stockpile and cut-off strategy, will bereviewed during the prefeasibility study to determine if it is feasible to adopt alternate operatingphilosophies that have the potential to reduce the overall disturbed footprint of the project whileachieving operational advantages and potential cost savings. One alternate operating philosophywould be to complete open pit mining in one of the deposits before commencing open pit miningin the other, while still providing a near simultaneous end of closure with the Boot Lakeunderground mine and the remaining open pit.2.4.4 Open Pit MiningConventional open pit shovel-truck methods will be used for mining the Main Zone and EastCleaver deposits. The mining function will be performed by the mine operator with purchasedequipment. The preliminary study has determined that the major open pit equipment fleet willconsist of one 18 m 3 hydraulic excavator as the primary waste mining unit, a 17 m 3 front endloader as the primary ore loading unit, ten 180 tonne-class off road haulage trucks, threeproduction drills, and various ancillary equipment. The prefeasibility study will review open pitmining equipment requirements, selection and sizing in order to optimize the mining fleet to theselected operating philosophy and material movement requirements.2.4.4.1 Production PlanThe East Cleaver open pit will be in operation at the same time as the Main Zone open pit, withthe Main Zone pit operating for 14 years and the smaller East Cleaver pit commencing 2 yearslater than the Main zone pit and operating for 8 years. The combined open pit total oreproduction will slowly decline over the years as the underground mine is brought up to fullproduction and the smaller East Cleaver pit is mined out. Total ore production from both openpits will peak at just over 10,000 t/d prior to the commencement of initial underground operationsat Boot Lake and fall to approximately 5,500 t/d in production year 7 upon commissioning of thepermanent Boot Lake mine underground ore and waste handling system to surface. This miningrate will be maintained until the completion of open pit mining from the East Cleaver deposit 3years later, whereupon the ore mining rate will be further reduced to approximately 3,000 t/duntil the completion of open pit mining from the Main Zone pit. Waste stripping will vary overthe life of the open pit mines, starting at approximately 14,700 t/d in production year -1,maintaining approximately 47,200 t/d for the first 6 years of production before slowly falling toan annual rate of approximately 1,600 t/d at the end of open pit operations. The average wastestripping rate is 30,000 t/d.Only one year of waste pre-stripping will be required in the Main Zone open pit prior to thecommencement of ore production due to the limited amount of overburden covering the MainZone deposit. In addition, water inflows to Camp Lake will be diverted, the lake drained, andlake sediments removed prior to open pit production mining.The preliminary plan has open pit mining occurring in two phases per deposit. Overlaps of thephases occur to balance waste stripping, high grade ore feed to the mill, and equipmentrequirements. The first phase of mining of the Main Zone deposit will occur on the northernshore of Camp Lake prior to commissioning of the mill and tailings facility. High grade oreproduced during this period will be stockpiled for use immediately upon mill start-up. Mining ofJanuary 2008 Hackett River Project – Project Proposal Sabina Silver CorporationReport Version B.1 2–12 Rescan Environmental Services Ltd. (Proj. #833-2)