MADISON, Wis. (AP) — Aquila Resources plans to sell its interests in copper and gold deposits in northern Wisconsin to a start-up company for about $5.8 million.

The Toronto-based company wants to focus on building its proposed Back Forty mine near the Menominee River in Michigan’s Upper Peninsula.

If the sale is approved, Aquila would receive nearly $2.5 million in cash and an ownership share of the new company worth about $3.3 million.

Aquila spokesman Dave Carew said additional details about the buyer will become available once the parties reach a definitive agreement within the next 45 days.

Carew said the buyer intends to raise additional money for exploratory drilling at the Bend and Reef sites, as well as publicly list its company on a Canadian stock exchange, Wisconsin Public Radio reported.

Aquila first explored the Bend and Reef mineral deposits in Taylor and Marathon counties about a decade ago. According to the state Department of Natural Resources, the Reef deposit in Marathon County contains 454,000 tons of high-grade gold reserves while the Bend deposit in Taylor County contains about 4 million tons of mostly copper and gold.

Environmental groups, Wisconsin tribes, and those living near the mineral deposits are concerned that targeting metals in underground sulfide deposits, known as sulfide mining, will impact water quality or quantity.