FAIRBANKS — Environmental regulators have fined Usibelli Coal Mine for almost a dozen cases where mining water made its way into Interior rivers and creeks.

The U.S. Environmental Protection Agency said Tuesday morning Usibelli has agreed to a $60,000 fine. It said the fine penalizes 11 “unpermitted discharges” into the Nenana River and Hoseanna, Sanderson and Francis creeks between April 2007 and mid-2010 and 10 other cases where the firm violated its permit guidelines.

Fred Wallis, a vice president for the mine, said Usibelli reported the cases itself. He said the water discharges occurred when heavy rain overwhelmed collection ditches.

EPA Compliance Unit spokeswoman Eva DeMaria agreed the discharges were accidental, but, she said, they could have been prevented with better maintenance and planning.

She said rain that falls on mining pits must be collected in ponds and ditches, where sediment settles out before the water can be released legally. In some cases, she said, the holding areas were too full of sediment residue.

“If they’d cleaned out their ponds regularly, these discharges wouldn’t have happened,” she said.

DeMaria said the discharges each involved either hundreds or thousands of gallons of water.