Engineering & Mining Journal

JUL 2018

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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REGIONAL NEWS - U.S. & CANADA 10 E&MJ • JULY 2018 www.e-mj.com icant step for the company as we progress the project toward production," Fireweed CEO Brandon Macdonald said. "Project economics in the PEA demonstrate that Macmillan Pass is not just viable at the zinc, lead, and silver prices levels contem- plated in the study, but is highly robust. With consideration of the exploration up- side, the project is steadily shaping up to be a premier, district-scale zinc mining camp in the mining-friendly Yukon Territory." The Macmillan Pass PEA was pre- pared by JDS Energy and Mining, with work on tailings and water by Knight Piésold Consulting. Highland Copper Advancing Copperwood Project Highland Copper Co. has reported the results of a feasibility study of its 100% owned Copperwood project at the west- ern end of Michigan's Upper Peninsula. Average annual life-of-mine production is forecast at 61.7 million pounds (lb) of copper and 100,570 ounces (oz) of silver in concentrate over a mine life of 10.7 years. Subject to completion of financing and receipt of all necessary permits, con- struction could begin in January 2019, followed by a 27-month construction pe- riod, commissioning in the first quarter of 2021, and commercial production begin- ning in the second quarter of 2021. Initial capital expenditures to develop the Copperwood project are estimated at $245 million, net of pre-production reve- nue of $30 million. Underground mining would be based on a conventional drill-and-blast, room- and-pillar mining method, with mine ac- cess via a decline. Mining operations are planned to operate two 10-hour shifts per day, 360 days per year to achieve a pro- duction target of 2.4 million metric tons per year (mt/y), or 6,600 mt per day (mt/d). Highland is studying the use of tailings as backfill in the open stopes. If this approach is selected, it would provide cost savings for tailings disposal and closure costs. The Copperwood processing plant is de- signed for a nominal throughput of 6,600 mt/d and planned availability of 91.3%. The flowsheet consists of semi-autogenous grinding in closed circuit with a ball mill, targeting a primary grind of 40 microns; rougher flotation with concentrate regrind; cleaner flotation using three stages of cleaning; concentrate thickening; filtra- tion; and tailings disposal. Studies are under way to evaluate the optimal destination and transport option for Copperwood concentrate. The Copperwood project is based on proven and probable reserves of 25.4 mil- lion mt grading 1.43% copper and 3.83 g/mt silver, containing 801.8 million lb of copper and 3.1 million oz of silver. Ad- ditional inferred mineral resources total 49.9 million mt grading 1.15 % copper and 3.42 g/mt silver, containing 1.3 bil- lion lb of copper and 5.5 million oz of silver, using a 1% copper cut-off. Kinross Moves Forward With Gilmore Expansion in Alaska Kinross Gold Corp. said it is proceeding with the initial Gilmore expansion project at its Fort Knox mine in Alaska. The initial Gilm- ore project is expected to extend mining at Fort Knox by six years to 2027, and leach- ing to 2030, at a low-initial capital cost of approximately $100 million, and increase life-of-mine production by approximately 1.5 million Au equivalent ounces (oz). The project is expected to generate an internal rate of return (IRR) of 17% and net present value (NPV) of $130 million based on a $1,200/oz. gold price, and an IRR of 26% and NPV of $239 million based on a $1,300/oz. gold price. "We are pleased to proceed with the initial Fort Knox Gilmore project, a low- risk, low-cost brownfield expansion that is expected to extend mine life to 2030 at one of our top performing operations and contribute 1.5 million gold equiva- lent ounces to strengthen our long-term U.S. production profile," said J. Paul Rollinson, president and CEO. "The Gilmore project offers an attractive IRR and NPV and adds to our suite of quality development projects at Tasiast, Round Mountain, Bald Mountain and Kupol to enhance our globally diverse portfolio." The project plan requires minimal construction of new infrastructure and new equipment purchases, including us- ing Fort Knox's current fleet and leverag- ing assets from its other North American operations as replacement equipment is required, the company said. Early construction work on the new heap leach and dewatering is expected to begin in the third quarter of 2018, with stripping commencing in 2019. Initial pro- duction from Gilmore is expected in early 2020, with approximately 5% of Gilmore ore expected to be stacked on the existing pad. Approximately 95% of Gilmore ore is expected to be stacked on the new heap leach pad, with stacking commencing in late 2020. Currently, milling at Fort Knox is expected to end in late 2020. Kinross is a Canadian-based senior gold mining company with mines and projects in the United States, Brazil, Rus- sia, Mauritania, Chile and Ghana. A cross section of Fort Knox as of December 31, 2017, shows the current mining surface (black), the pre-Gilmore reserve pit (orange), post-Gilmore reserve pit (green) and post-Gilmore resource pit (yellow). (Continued on p. 25)

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