by Larry Campbell, Darby
The Sheep Creek mine project at the head of the West Fork could hardly be in a riskier place. Of course, US Critical Materials did not pick that spot for a rare earth elements deposit, nor did they have anything to say about other minerals in the matrix rock and associated with the rare earth elements in the ore veins.
One of those minerals is actinolite, a close relative of tremolite that killed over 400 people around Libby’s vermiculite mine. Both are asbestos in their fibrous form. Libby’s tremolite asbestos lurked in the shadows for decades until some determined citizens brought the hidden killer to light.
Possible actinolite asbestos was a topic of passionate concern associated with the Skalkaho vermiculite mine near Hamilton in 1999. The question of asbestos was not addressed by officials until the mine was almost permitted. The Bitterroot NF completed a Final EIS before belatedly deciding to require a Supplemental EIS to evaluate potential for asbestos exposure. The mining company folded before testing.
Roadside Geology of Montana states, “Several early attempts to mine vermiculite in the Skalkaho intrusion went poorly. While at one time that seemed unfortunate, now it’s clear that we narrowly escaped having another major [asbestos related] environmental disaster.”
To be clear, nobody knows if there is asbestos at Sheep Creek.
But there is good reason to suspect asbestos may be there. Geologists at Montana Tech report that actinolite is one of the most common matrix minerals in the host rock, and the veinlets containing ore are “actinolite-rich.” The Montana Bureau of Mines and Geology Crowley Bulletin reports actinolite at Sheep Creek “forms masses of radiating fibers surrounding other crystals.”
US Critical Materials has sampled ore for several years and tested for a long list of analytes. Why not test for asbestos? The sooner the better to allow for informed agency management and avoid spreading asbestos around if it’s there.
Asbestos exposure happens by breathing contaminated dust, which is very hard to contain and clean up. Mining is dusty business.
Contact BNF Supervisor Matt Anderson matthew.anderson3@usda.gov and Ranger Dan Plileydaniel.pliley@usda.gov about possible asbestos at Sheep Creek.