Highland Copper Co. Inc. outlined results of a feasibility study on its Copperwood copper project in Michigan, estimating the after-tax internal rate of return at 18% and the net present value, discounted at 8%, at US$116.8 million

The feasibility study was framed around 25.4 million tonnes of proven and probable reserves grading 1.43% of copper and 3.83 g/t of silver. The project also hosts inferred resources of 49.9 million tonnes grading 1.15% copper and 3.42 g/t of silver.

Highland Copper projected the project's mine life at 10.7 years with average annual production of 61.7 million pounds of copper per year and 100,570 ounces of silver. It pegged the initial capital cost at US$245 million.

The proposed underground mining method would be room-and-pillar, which is commonly used for flat-lying deposits. The throughput rate of processing facilities would 6,600 tonnes per day, with copper recoveries ranging between 77% and 90% and copper concentrates grading between 20% and 29% copper.

Highland Copper said the project still requires state and federal permits, and it is evaluating the "optimal destination and transport" options for Copperwood concentrates.

The company said that with the feasibility study done, it can focus on sourcing funding to develop the underground mining project. As of March 31, Highland Copper reported US$7,341,210 in cash and cash equivalents.