Revett: Troy sinkhole isn't linked to mining

SANDPOINT — The sinkhole at the Troy mine in northwestern Montana was not related to previous mining activity, Revett Silver Company announced late Wednesday.

Revett said that conclusion was reached following an independent technical review conducted by Call & Nicholas, a firm in Tucson, Ariz.

"We said all along people should not speculate nor jump to premature conclusions until the facts were established," said Carson Rife, vice president of operations. "This independent report belies charges made almost immediately by our Rock Creek proposal's critics that this validated their false charges regarding our proposed project."

The 30-foot-wide and 50-foot-deep sinkhole emerged over the old workings of the Troy Mine in early May, prompting Revett's detractors to become concerned that subsidence could plague the Rock Creek Mine proposed nearby. Both mining projects are owned by Revett.

The 18-page report written by Call & Nichols' Vice President Paul Cicchini said it is impossible to completely rule out any mining connection, but said all the evidence pointed to no relationship. Cicchini also noted critics were quick to jump on a north/south trending fault structure in the areas as the cause.

"It appears much more likely that the surface sinkhole was the result of collapse and erosion of surface colluvium into a void along a dilated segment of an east/west trending structure," Cicchini said.

Cicchini said a "cursory examination" of the situation could lead to a quick conclusion that the sinkhole was directly related to mining, but said there is ample evidence which points to the contrary.

"Science and facts are what should drive the debate regarding Rock Creek, not misinformation or patently incorrect statements which our critics are all too prone to employ," Rife said. "Rock Creek has specific safeguards built into the project in the form of buffer zones around lakes and outcrop areas, along with avoidance of fault structures to eliminate subsidence potential."