Wisconsin Republican Gov. Scott Walker has signed a bill expediting environmental regulations ahead of a possible $1.5 billion mine, one of the biggest in the nation. Over objections by environmental groups like the Sierra Club and indigenous tribes, Gov. Walker said the legislation “will preserve our tradition of clean land, water and air,” while establishing a 420-day limit for officials from the state’s to approve or deny a mining permit.

Gogebic Taconite has planned a $1.5 billion mine in portions of Iron and Ashland counties in Wisconsin’s far. Company officials have added the project could lead to 700 mining jobs, more than 3,000 construction jobs and $604 million in overall economic benefits. If brought to production, the mine would be one of the largest in North America, according to the National Mining Association (NMA).