Canadian Mining Journal


ZINC-COPPER-GOLD: Aquila shares positive FS for the Back Forty project

Examining core from the Back Forty zinc-copper-gold deposit in Michigan. (Image: Aquila Resources)

MICHIGAN – Toronto-based Aquila Resources says the feasibility study for an open pit at the Back Forty zinc-copper-gold project on the Upper Peninsula is positive. The after tax net present value with a 6% discount rate is $208 million (all figures are U.S. dollars) and the internal rate of return will be 28.2%.

Aquila calls the completion of the feasibility study a milestone. The property is fully permitted and is close to existing infrastructure. The company is ready to begin the pre-construction phase as it considers funding options.

Building an open pit  and mineral processing plants will take two years and cost $294 million. Sustaining costs will be $110 million. Over a seven-year life, the Back Forty will produce 468,000 oz. of gold, 512 million lb. of zinc. A portion of the resources are amenable to underground mining.

There are four styles of mineralization in the deposit: 1) zinc or copper rich massive sulphide containing significant amounts of gold and silver; 2) stockwork stringer and peripheral sulphide which can contain gold, zinc and copper; 3) low sulphide mineralization containing only precious metals; and 4) oxide rich, precious metal bearing gossan.

The Back Forty has proven and probable reserves of 11.65 million tonnes in both open pit and underground portions. The deposit averages 2.64% zinc, 1.85 g/t gold and 0.28% copper. The mill will treat 4,000 tonnes of sulphide ore and 800 tonnes of oxide ore per day.

Details of the feasibility study are available in the news release of Aug. 1, 2018, at or visit