The federal government may have to return nearly a half-million dollars to mine claim holders in Idaho if a federal class-action suit is successful.

In a ruling last week, a federal judge sided with an Idaho company that argued because of law changes, it should be reimbursed maintenance fees paid in 2013 to the Bureau of Land Management.

Silver Buckle Mines, Inc., an Idaho company with 87 hard-rock mining claims on public lands in the state, filed suit against the government, alleging it had unnecessarily paid the fees, and Judge Margaret M. Sweeney agreed.

In her opinion, Sweeney, of the U.S. Court of Federal Claims, said Silver Buckle was entitled to recover the 2013 maintenance fees paid on its pre-1993 unpatented, nonplacer — or, hard-rock — mining claims.

Silver Buckle says it will pursue a class-action suit against the government, something the federal court will also allow, according to the opinion.

“Further,” Sweeney wrote in her opinion, “plaintiff has satisfied the numerosity, commonality, adequacy, and superiority requirements for class-action certification.”

The suit alleges verbiage in amendments to the mining law, adopted between 1993 and 2013, exempted the payment of maintenance fees for hard-rock claims that were registered before 1993, although the government still collected the fees.

The suit affects 3,120 active lode claims in Idaho and 252 mill sites, according to the BLM. Claim holders paid $140 in maintenance fees to the government for each claim.

Most mining claims in Idaho were filed after 1993 and are not subject to reimbursement, according to the suit.

The bulk of the state’s mining claims are in Shoshone County, according to BLM data, where 2,800 active claims for silver, gold, copper, lead and zinc were listed last month. Kootenai County has 21, and one active claim is registered in Benewah County.