The legal fight over the Montana Department of Environmental Quality’s approval of a central Montana copper mine made an appearance in the Montana Supreme Court Wednesday. During an hour-long hearing, justices dove deep into weedy regulatory issues focusing on the safety of storing mine tailings and how the mine is expected to influence water quality in Sheep Creek, a tributary of the Smith River.

The Black Butte Mine, which is expected to produce 14.5 million tons of high-grade copper over its 13-year operational life, is the focus of the lawsuit. After finishing a multi-year review and producing more than 90,000 pages of administrative records, the DEQ in April of 2020 approved Tintina’s application to move forward with the mine near White Sulphur Springs.