Senate panel hears bill to clarify when mine detention ponds are in compliance after storms

Senate Natural Resources Committee members heard testimony on Senate Bill 365 on Jan. 20, when sponsor Sen. Barry Usher said the measure would clarify compliance determinations for mine-site detention ponds that overflow after back-to-back storms.

The bill would specify that a detention pond designed under current rule for a 10-year, 24-hour storm is not automatically out of compliance if a series of storms fills the pond, provided the pond was designed to rule specifications and the operator is working “towards dewatering the detention pond in a timely fashion.”

Proponents from the coal industry said the change is a technical clarification that preserves mines’ responsibility for water quality while avoiding automatic penalties. Opponents, including the Montana Environmental Information Center and ranchers, urged stronger language tying the bill to federal Clean Water Act obligations and expressed concern about reduced public notice and enforcement incentives.

"All SB 65 does is specify that as long as the…