HUMBOLDT, MI-- Rio Tinto officials say an absorbent clay slurry has been released into wetlands near the Humboldt Mill.
The Eagle Mine recently began construction of a cut-off wall designed to prevent water from a nearby pit full of tailings from flowing into the wetlands. Officials say they first filled a trench with a non-hazardous clay sealant called bentonite to prevent the pit water from escaping. But on Monday workers hit an underground channel, allowing the bentonite slurry to flow into the adjacent wetland.
Rio Tinto says work is under way to clean up the bentonite. Regulators and the Superior Watershed Partnership have been notified of the incident—per an agreement under the Community Environmental Monitoring Program—and have inspected the wall.
Officials say because more slurry could flow into the wetlands as the wall is constructed, mitigation measures are being put in place to protect the nearby river system and lands.
