MADISON, Wis. — A northern Wisconsin legislator who authored changes relaxing Wisconsin’s iron mining regulations now wants to lift the state’s mining moratorium.

Gov. Tommy Thompson signed the moratorium into law in 1998. It requires companies to prove a sulfide mine has operated for a decade without polluting groundwater and surface water with acid drainage. The measure also requires that a sulfide mine has been closed for a decade in the state without polluting the water. The state Department of Natural Resources can’t issue a mining permit unless both conditions exist.

Wisconsin Public Radio reported Tuesday that Republican Sen. Tom Tiffany of Hazelhurst plans to introduce a bill this session repealing the moratorium. Tiffany told the radio network that the Flambeau copper mine near Ladysmith proves a sulfide mine can operate safely, making the moratorium moot.

That mine operated for four years, shutting down in 1997. U.S. District Judge Barbara Crabb in 2012 found the mine discharged copper into state waters but said the pollution was minimal. An appellate court reversed the judgment in 2013.

Tiffany told The Associated Press on Thursday that since the Flambeau mine satisfied the moratorium’s conditions there’s no need to keep the statutes on the books. He acknowledged that the mine operated for only four years but said the court rulings show the mine didn’t pollute while it was running. He added that he believes the caveat that a mine doesn’t pollute for a decade after closure is the most important standard and the mine met that.

“The closure is the key issue,” he said. “We want to make sure we don’t leave problems for future generations.”

Tiffany rose to prominence by writing a contentious bill in 2013 that relaxed iron mining regulations to ease the path for Gogebic Taconite’s plans for a $1.5 billion iron mine near Lake Superior. The company abandoned the project in 2015.

Tiffany said no companies have approached him with proposals to mine specific deposits.

Lucas Vebber, director of energy and environmental policy for Wisconsin Manufacturers and Commerce, told Wisconsin Public Radio that lifting the moratorium has been on the group’s agenda for years.

Democratic Sen. Janet Bewley of Ashland said the moratorium should remain in place and Tiffany’s bill would distract from state budget deliberations.