HELENA, Mont. (AP) — The Montana Supreme Court has removed a big obstacle for a mining company seeking to explore a silver and copper deposit potentially worth billions of dollars under the Cabinet Mountain Wilderness in northwestern Montana.

Exploration of that deposit has been delayed in part by a long-running dispute over whether Mines Management Inc. can access it by using a tunnel that goes under a man’s nearby mining claims.
In a 5-0 decision Tuesday, the justices ruled that the late Arnold Bakie’s mining claims weren’t valid because they contained no valuable minerals. Justices said a lower-court judge was wrong to rule that Mines Management owed Bakie money for going under his claims to get to the deposit.
Bakie and an investment group that included former Montana Gov. Brian Schweitzer had alleged Mines Management’s use of the tunnel through the claims was trespassing. Company officials accused Bakie and the investors of using the claims to block development in order to squeeze cash and stock out of Mines Management.
Luke Russell, a spokesman for Hecla Mining Co., which owns Spokane-based Mines Management, said Tuesday the ruling confirms what the company believed all along —that it has the right to access its patented mineral claims.
However, the ruling doesn’t clear the company to start mining the Montanore project. Mines Management is working with the U.S. Forest Service on an environmental analysis of its planned exploration to assess the project’s feasibility, which seeks to mine a multibillion-dollar silver and copper deposit, Russell said.
The analysis will assess the project’s potential effects on the environment and the plants and animals in the area.
Bakie had filed four mining claims based on quartz deposits that were found in the area, claims that were right in the path of the rich copper and silver deposit.
Mines Management sought a ruling in 2007 that Bakie’s claims were invalid, and the state Supreme Court ruled that none of the quartz was actually found on Bakie’s claims.
The ruling has the effect of overturning a $3.3 million judgment against Mines Management.
Jurors had awarded $2.575 million in damages to Bakie, 70, two days before he died in a logging accident last November. It also awarded $750,000 to Optima, a group of investors, including former Gov. Brian Schweitzer, that agreed to pay Bakie at least $700,000 and up to $1.1 million to acquire his mining claims.
Bakie was also a member of Optima, which had sought $10 million in cash and stock from Mines Management as compensation for access under the claims.
Mines Management CEO Glenn Dobbs told The Associated Press in 2015 that Schweitzer’s investment group tried to obstruct the development of the Montanore mine with the intent of gaining money and ownership in the company.
Neither Amy Guth, an attorney for Bakie’s estate, nor Alan McCormick, an attorney for Optima, returned calls seeking comment.