SANDPOINT — The Sandpoint-based Rock Creek Alliance is greeting news of a 40-ton spill of slurried waste at the Troy mine with dismay.

Revett Minerals confirmed on Friday that sensors detected a leak in a pressurized tailings pipe, prompting workers to immediately shut down the northwestern Montana mine’s mill.

“We did have a minor incident at Troy,” Carson Rife, vice president of operations at Revett, said in a message to The Daily Bee on Friday.

Rife was not immediately available for further comment, but told The Missoulian newspaper more than 88,000 pounds of tailings had been released, some of into Stanley Creek, which flows into Lake Creek.

The tailings, which consisted of water and fine sand, were released on Wednesday.

“It didn’t seem like the spill was going to contain any toxins,” Lisa Peterson of the Montana Department of Environmental Quality told The Missoulian.

But while Revett and regulators in Montana downplayed the effects of the spill, news of the release drove up the anxiety of Rock Creek Alliance, which is fighting to stop the proposed Rock Creek mine, another Revett project.

Revett officials often point to Troy as a working example for the Rock Creek mine, as was done by Revett CEO John Shanahan when he authored an editorial in The Missoulian on Aug. 21.

“They keep shoving Troy in our face,” said Jim Costello, Montana coordinator for Rock Creek Alliance. “They keep saying what a great job they do at Troy and that’s what a great job they’ll do at Rock Creek. Well, the facts speak for themselves.”

Revett proposes to tunnel beneath the Cabinet Mountains Wilderness to extract copper- and silver-laden ore.

The company calls the Rock Creek mine one of the most tightly regulated proposals in the history of hard rock mining, although critics contend it could have devastating impacts on the wilderness and on water quality in the Clark Fork River, which flows into Idaho’s Lake Pend Oreille.