Capstone Mining Corp. posted an updated technical report for its polymetallic Cozamin mine in Zacatecas, Mexico, outlining an 89% increase in reserves and plans to increase production by 30%.
Cozamin hosts probable reserves of 6.2 million tonnes grading 1.60% copper, 42.89 g/t silver, 0.71% zinc and 0.14% lead. Contained metal is estimated at 99,000 tonnes of copper, 8.5 million troy ounces of silver, 44,000 tonnes of zinc and 8,000 tonnes of lead.
Reserves are included within measured and indicated resources totaling 17.3 million tonnes grading 1.50% copper, 45 g/t silver, 1.25% zinc and 0.28% lead, while inferred resources increased to 17 million tonnes grading 1.11% copper, 44 g/t silver, 1.65% zinc and 0.29% lead.
The analysis used a US$50 net smelter return cutoff based on metal prices of US$3.50/lb of copper, US$18/oz of silver, US$1.20/lb of zinc and US$1/lb of lead as well as metal recoveries of 95% copper, 78% silver, 58% zinc and 40% lead.
Capstone plans infill drilling on the Mala Noche Footwall Zone at Cozamin, aiming to upgrade additional resources.
The company also said Dec. 10 that a materials-handling study completed as part of the technical report indicated congestion on the main haulage ramp, limiting the mine's ability to bring ore to the surface.
The company plans to convert the Cozamin haulage network from a two-way single ramp to a one-way ramp loop, which is expected to be completed by the end of 2020 to increase production approximately 30% to 3,780 tonnes per day at costs of less than US$5 million.
Annual copper production at the mine is expected to increase to between 40 million and 45 million pounds as a result. As of January, Cozamin was expected to produce about 33 million pounds of copper in 2018; it produced about 37 million pounds in 2017.