KSM

Overview

The Kerr-Sulphurets-Mitchell (KSM) project is located in the rugged Coastal Mountains of British Columbia, Canada.

The mineral deposit is a gold enriched prophyry system hosting 1.6 billion tonnes of 30.2 Moz gold, 7 billions pounds of copper, 133.1 Moz silver and 210 million pounds molybdenum.

Mining would be carried in three different open pits over a 35 years mine life.

Processing plant would have an average capacity of 120,000 tpd and would consist of crushing, grinding, flotation and cyanide leaching.

Concentrates would be trucked for 200 km and then loaded on oceanic ships and  shipped to oversea smelters.

Location

The Kerr-Sulphurets-Mitchell (KSM) property is located in northwestBritish Columbia, about 950 kilometers northwest ofVancouver. The property consists of 30 contiguous mineral claims and 19 contiguous placer claims that cover an area of about 6,726 hectares. 

The property lies in the ruggedCoastalMountainsof northwestBritish Columbia, with elevations ranging from 520 m in Sulphurets Creek valley to over 2,300 m at the highest peaks. Valley glaciers fill the upper portions of the larger valleys from just below tree line and upwards. The glaciers have been retreating for at least the last several decades. 

The climate is generally that of a temperate or northern coastal rainforest, with subarctic conditions at high elevations. Precipitation is high. The length of the snow-free season varies from about May through November at lower elevations, and from July through September at higher elevations. 

Access to the property is via helicopter.

Geology and Mineralization

The KSM property is a gold enriched copper porphyry system controlled by a series of dikes, sills and plugs rather than a single stock. Mineralization is typically associated with quartz veinlet stockworks and sheeted quartz veinlet arrays mainly in altered host rocks adjacent to the intrusions. 

The KSM proven and probable reserves consist of 1.6 billion tones containing 30.2 Moz gold, 7 billion pounds copper, 133.1 Moz silver and 210 million pounds molybdenum.

Mining & Operation

 Mining activities would span 35 years and would see the development of three different pits. Production is scheduled to commence at the Mitchell deposit, to be augmented by Kerr and then Sulphurets. 

The mining operations will be typical of open-pit operations in mountainous terrain in westernCanada, and will employ typical open pit mining methods and equipment. 

The KSM pit designs are based on the digging reach of the large shovels (15 m operating bench) with double benching between highwall berms; therefore, the berms are separated vertically by 30 m. 

Six 100 telectric cable shovels are matched with the 363-t truck. Two Diesel hydraulic shovels (85 t) are added to the fleet when a smaller more mobile loading unit is needed for development etc. The 85-t units loading the 363-t trucks are suitable as production shovels as well.

The blast hole drills will be fitted with GPS navigation and drill control systems to optimize drilling. The GPS navigation will enable stakeless drilling and is recommended for efficiency in locating hole locations and accuracy of set-up articularly since this is a high snow fall area. The drills will also be fitted with automatic samplers to provide grade control samples from the drill cutting in the ore zones. These samples will be used for blast hole kriging to define the ore/waste boundaries on the bench as well as stockpile grade bins for the grade control system to the mill.

Two Diesel hydraulic and six electric rotary drills (311 mm bit size) will be used for production drilling, both in ore and waste.

 A 6½ inch (165 mm) diesel hydraulic percussive drill is also specified to operate in all pit phases for controlled blasting techniques on high wall rows and development of initial upper benches. 

Ore and waste haulage will be handled by 55 large off-highway haul trucks with a 345-t payload. 

Mine support equipment fleet include: two 3 t hole stemmers (blast hole stemmer); five 630 KW track dozers (shovel support); four 250 KW rubber tired dozers (pit clean up); two fuel/lube trucks (shovel and drill fuelling and lube); two 14t wheel loaders multipurpose (pit clean up); four 20,000 gallons water trucks (haul roads water trucks); four 430 KW track dozers (dump maintenance); five 400 kW motor graders (road grading); two 220 kW motor graders (road grading); and, two tire manipulators (tire changes). 

The mine’s ancilliary equipment fleet include one 430 kW track dozer (pit support); one 189 t float tractor/trailer; three 6t hydraulic excavators (utility excavators); six 1,400 gal/min sump pumps (pit sump dewatering); six lighting plants; two 250t utility cranes; twenty crew cabs; one ambulance; two 4t hydraulic excavators; one mine rescue truck; two crew buses; six 1t maintenance trucks; one fire truck; one screening and crushing plant (12 inch maximum used for road crush and stemmings); two picker trucks (maintenance + overhauls); six 37t scrapers (crush haul for winter roads, drill steels, etc); three 40t hydraulic extendable utility cranes; one 14t wheel loader (road crush loader); six snowcats; two 100t utility cranes; one 30t forklift; two 10t forklifts; five service trucks; four welding trucks and two powerline maintenance trucks.

Geological hazard management during mining of the proposed pits will be important. Additional engineered structures adjacent to the pit or modifications to the pit slope geometry may be required for snow avalanche mitigation. 

Landslides have been noted in the area as a result of the region being recently deglaciated; they require additional work to develop appropriate mitigation plans.

Processing

The mill feed from the Mitchell, Sulphurets, and Kerr deposits will be processed at an average rate of 120,000 t/d. 

The process plant will consist of three separate facilities: an ore crushing/grinding and handling facility at the mine site, a Mitchell-Teigen ore slurry tunnel transportation system, and a main process facility at the Teigen area site, adjacent to the TMF. Processing at the Teigen area plant site will include secondary grinding, flotation, regrinding, leaching, and dewatering. 

The comminution plant at the Mitchell valley mine site consists of three stages of crushing and one stage of grinding. The crushing will include primary crushing by gyratory crushers, secondary crushing by cone crushers, and tertiary crushing by HPGR. The primary grinding circuit consists of four conventional ball mills. 

The ground mill feed will be transported through one of the Mitchell-Teigen twin tunnels (MTT) by two stages of pumping to the Teigen plant site northeast of the KSM mine. This tunnel will also be used for electrical power transmission, diesel fuel delivery by pipeline, and return of reclaim process water from the Teigen plant site to the primary grinding plant at Mitchell. The adjacent tunnel will be used for the transport of personnel and supplies for the mines operating and water management activities. 

The plant site will consist of secondary grinding, flotation, concentrate dewatering, cyanide leaching, gold recovery, and tailing management facilities. 

The grinding circuits will consist of eight energy efficient tower mills in closed circuit with hydrocyclones. The ground ore will be subsequently concentrated by conventional flotation to produce a copper-gold-molybdenum concentrate and a gold-bearing pyrite concentrate for gold leaching.. The concentrates will be dewatered and shipped to copper and molybdenum smelters. 

The gold-bearing pyrite flotation concentrate together with the cleaner flotation tailing from the copper-gold-molybdenum cleaner circuit will be leached with cyanide for additional gold and silver recovery. Prior to storage in the TMF, the pulps from the cyanide leaching circuit will be washed, and subjected to cyanide recovery and destruction. 

The flotation tailing and the washed leach residues will be sent to the Tailing Mangement Facility (TMF) for storage.

The ultimate dam crest elevation of 1,095 m TMF is designed to store 1.62 Bt of tailing produced over a 37-year mine life.

Two diversion tunnels have been included to route water around the mine area. The tunnels are designed to accommodate a 1-in-200 year storm.

The proposed permanent road access routes to the mine and plant site include a 35 km road south from the Eskay Creek Mine site and a 14 km road southwest from Highway 37. These roads will provide access for supplies, equipment and crew transport, and will be used for hauling concentrate to Highway 37. 

A proposed winter access road that leads to the KSM mine will be constructed.

Copper concentrates (averaging approximately 820 t/d) produced at the process site will be filtered at the plant site and transported 200 km by contract trucking firms on Highway 37 and 37A to a storage and concentrate loading facility site near Stewart, BC. Concentrates would be loaded and shipped via ocean transport to overseas smelters.

Environment & Community

The Rock Storage Facilities (RSF) will be placed close to their final closure configuration and recontoured as necessary. The RSFs will be primarily built bottom-up to result in stable dump slopes during operation and closure. As the MTRSF will be a flat-topped valley fill, the possibility of using a closure cover of neutral tailing (to reduce infiltration) will be examined during the Feasibility Study. 

The dam faces will be either covered with an erosion protection layer, or covered with till and revegetated using soil stockpiled during construction of the dams. 

Upon closure, the hydroelectric plants will remain in operation, generating more power than required to operate the treatment plant and generating income to offset treatment costs.