Highland Copper Advancing Copperwood Project

Highland Copper Co. has reported the results of a feasibility study of its 100% owned Copperwood project at the western end of Michiganís 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, construction could begin in January 2019, followed by a 27-month construction period, commissioning in the first quarter of 2021, and commercial production beginning in the second quarter of 2021.

Initial capital expenditures to develop the Copperwood project are estimated at $245 million, net of pre-production revenue of $30 million.

Underground mining would be based on a conventional drill-and-blast, roomand- pillar mining method, with mine access via a decline. Mining operations are planned to operate two 10-hour shifts per day, 360 days per year to achieve a production 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 designed 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; filtration; 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 million 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. Additional inferred mineral resources total 49.9 million mt grading 1.15 % copper and 3.42 g/mt silver, containing 1.3 billion lb of copper and 5.5 million oz of silver, using a 1% copper cut-off.

As featured in Womp 2018 Vol 07 - www.womp-int.com