Project developer Aquila Resources is awaiting issuance of the amended mining permit and air permit for its Back Forty zinc and gold project, in the US, after the state of Michigan environmental review panel upheld the mining permit.

The decision by the panel marks the final step in the contested challenge to the mining permit that began in April 2018 and is the Michigan Department of Environment, Great Lakes and Energy’s final decision, the company said on Wednesday.

In May this year, an Administrative Law Judge upheld the final decision and order on the nonferrous metallic mineral mining permit for Back Forty.

Following the judge’s ruling, the Menominee Indian Tribe of Wisconsin appealed the decision to the environmental review panel, which is made up of technical experts from various fields.

The three-person panel adopted the Judge's May 3, decision, which found "that the proposed mining operation will not pollute, impair, or destroy the air, water and other natural resources, or the public trust in those resources”, in compliance with Michigan's nonferrous metallic mining statute.

"We are pleased that the panel ruled in our favour and adopted the Judge's comprehensive decision that followed an exhaustive review process and lengthy contested case hearing,” commented Aquila president and CEO Barry Hildred.

Back Forty is an openpit volcanogenic massive sulphide deposit with underground potential located along the mineral‐rich Penokean Volcanic Belt in Michigan's Upper Peninsula. The project contains about 1.1-billion pounds of zinc and one-million ounces of gold.

According to a 2018 feasibility study, the project has a life of seven years with total payable gold production of 468 000 oz, at an average of 67 000 oz/y. The total payable zinc production is about 512-million pounds, at an average of 73-million pounds a year.

Initial project capital costs were estimated at $294-million with a 24-month construction period, and sustaining capital costs were valued at about $110.6-million.

Aquila, which trades on the TSX, has received all state and federal permissions required for the construction and start of operations at Back Forty.