Yukon’s Mining Foundation
Minto Mine (Capstone Mining Corp.) is operating an open pit copper-gold mine, with a current capacity of 3,600 tpd. It has gone through five phases of increased production and has increased resources since its production start up in late 2007. It had an exploration budget of $4.8 million for 2012, to develop resources and reserves in nine discovery zones.
These zones occur over a strike length of 3.5 kilometres at the existing Minto mine, which has mined out the Minto Main pit in mid 2011, and now, is processing the ore stockpiles. Minto released a Pre-Feasibility study June 18, 2012 for its Phase VI expansion, which outlined the incorporation of new mineral reserves and a new life-of-mine plan (LOMP) that includes the additional underground mineral reserves from the Copper Keel and Wildfire zones; optimized pit designs; processing plant capacity improvements; and updated costs and economic analysis.
The open pit proven and probable reserves have a total of 9.1 million tonnes, grading 1.39 per cent Cu, 0.52 g/t Au and 4.48 g/t Ag. The Phase VI expansion would increase the mine life to 2022, with a capital cost of $103 million.
Minto Mine is spending $7 million to upgrade its main camp facility to enhance retention and recruitment of staff. The first phase expected to be completed next summer and will include a 90-room, three-storey facility which will have recreation facilities. Minto will be using an underground contractor for underground development and in the second half of 2013, Minto Mine will takeover the underground mining with its own staff.
Bellekeno Mine (Alexco Resources Corp.) is producing high-grade silver (800 g/t Ag) at a rate of about 250 tpd (mill capacity is 400tpd) in Keno Hill District, near Mayo.
Established in 2005, the Bellekeno Mine is Canada’s only primary silver producer. It produced 2 million ounces of silver in 2011, with an estimate of 2.2 million ounces of silver production for 2012. About 50% of mining is done using cut and fill with the balance being done using longhole stoping.
Alexco had an exploration budget for 2012 of about $12 million for an estimated 22,500 metres of surface drilling and 5,000 metres of underground drilling. Longer term, Alexco has a goal of producing 5 million ounces per year by developing other mines.
Alexco’s two advanced projects, are both former historic producers; Onek and Lucky Queen, both of which could be producing in 2013.
Lucky Queen has indicated resources of 124,000 tonnes grading 1,227 g/t of silver, 0.2 g/t of gold, 2.6% lead and 1.7% zinc, with inferred resources of 150,000 tonnes grading 571 g/t of silver, 0.2g/t of gold, 1.4% lead and 0.9% zinc.
The Onek development project has indicated resources of 585,000 tonnes grading 194 g/t of silver, 0.7 g/t of gold, 1.2% of lead and 13.7% zinc with inferred resources of 203 g/t of silver, 0.4 g/t of gold, 1.1% lead and 11.5% zinc.
The Alexco Environmental Group is focused on remediation with a mining focus, mine water treatment and consulting services for project permitting. Some historic mines are still releasing water with high metal content which must be perpetually treated for high metal content, although there is almost no acid water content.
The Elsa Tailings is both a silver resource and an environmental cleanup challenge, with an initial resource estimate of 2.49 million tonnes grading 119 g/t of silver.
The cleanup cost of the Elsa tailings is the largest part of the cleanup cost, estimated at about 50% of the total $60 million cleanup cost for the district, which is covered by the federal government. Remediation would involve picking up tailings, removing it and dry stacking. However, these tailings could be processed to extract the silver prior to final storage.
Alexco has a 233 km2 property position with a full exploration pipeline in various stages of development. It also has two important exploration discoveries, Flame & Moth, and the Bermingham. Other exploration projects are the Silver King, Husky, Onek SW, Elsa, Ruby, HC, K700 and McQueston.
Wolverine Mine (Yukon Zinc Corp.) is a zinc-silver-copper-lead-gold underground mine, with on-site milling capabilities of 1,700 tpd to produce zinc, copper and lead concentrates. It’s located 282 km northeast of Whitehorse. The current mine life is about 9.5 years based on a 5.2 million tonnes reserves.
Jinduicheng Molybdenum Group Co. Ltd. and Northwest Nonferrous International Investment Company Ltd, two Chinese companies, purchased shares of Yukon Zinc (formerly Expatriate Resources) in July of 2008
Yukon Zinc completed major site construction at Wolverine throughout 2009 and 2010. Mill commissioning commenced in late 2010, and production in 2012 is increasing to design capacity.
Yukon Zinc completed its tailings dam raise last summer, thereby bringing the facility to ultimate height for life of mine. In addition, it has implemented measures to further ensure underground safety.
Professor Rimas Pakalnis from UBC Mining Engineering, a specialist in underground geotechnical designs, did a comprehensive study for the mine ground conditions and a result, the ground support is now ensured by using 3.7-metre rock bolts on 1-metre spacing, with shotcrete and wire mesh.
Drift and fill is the mining method at Wolverine. This method was selected as a result of the flat lying layout of the deposit, varying horizontal thickness of the deposit, and the selectivity needed to achieve suitable waste dilution.
Mining is done on a contract basis by Procon. Wolverine uses a fleet of Sandvik for underground equipment.
Wolverine is producing a copper concentrate, a zinc concentrate and a lead concentrate. It’s using the research services of Beijing General Research Institute of Mining and Metallurgy for the metal recovery. The copper and lead concentrate is bagged while the zinc concentrate is sent in bulk concentrate.
Wolverine is also testing a water treatment plant using INOTEC (University of Utah) and Lorax Environmental (Vancouver) using a patented new technology called an “electro-biochemical reactor” for the removal of metal contaminants, and notably selenium, in the tailings supernatant.