BILLINGS, Mont. (AP) — Environmental groups have filed notice they plan to sue Gov. Greg Gianforte’s administration after it dropped a legal claim against a mining executive over decades of pollution from several mines. The Department of Environmental Quality in July quit a 2018 lawsuit that sought to block Idaho-based Hecla Mining Co. President Phillips Baker Jr., from involvement in two proposed silver and copper mines. Baker was an executive with Pegasus Gold, which went bankrupt in 1998, leaving state and federal agencies with more than $50 million in cleanup costs at three mines.