Two miners were injured Thursday while working to expand the Lucky Friday Mine in Mullan, Idaho.
One was hospitalized in critical condition, the Shoshone County Sheriff’s Office said Friday.
A second miner was treated and released, according to Amy Louviere of the federal Mine Safety and Health Administration.
The identity of neither miner has been released.
Mike Dexter, spokesman for Hecla Mining Co., the mine’s owner, said the workers were part of a crew constructing a new shaft 4,900 feet below ground. The miners are employees of Cementation USA.
The contractors were working on a 16-foot-diameter underground rock bin, Hecla said in a news release.
Louviere said the bin became plugged with material. When the miners entered the bin to dislodge it, “it started to flow and one of the miners became engulfed.”
Hecla said both men were wearing appropriate personal protection equipment.
The Shoshone County Sheriff’s Office received a 911 call about the accident at 11:40 p.m. Thursday. A crew from Mullan Volunteer Ambulance responded to the mine and transported both miners to Shoshone Medical Center, Undersheriff Rod Plank said Friday.
This is the same mine where a cave-in killed a worker in April due to work practices, according to federal investigators. Larry “Pete” Marek was buried in a 25-foot-high rock pile when his work area collapsed.
The integrity of a rock pillar that had provided ground support was compromised when the pillar was mined for its silver ore, according to a report by the Mine Safety and Health Administration.
Hecla was cited for unsafe ground conditions at the Lucky Friday in subsequent inspections during May, June and August.
In July, a fire inside the Lucky Friday Mine likely was set by an arsonist, according to the Sheriff’s Office. About 170 miners who were working in the shaft where the fire was detected July 26 were given polygraph tests, and an investigator from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives was investigating along with Hecla, the Idaho fire marshal’s office and Mine Safety and Health.
The Lucky Friday Mine employs about 275 workers in addition to contract crews who are sinking the new No. 4 shaft where the accident occurred Thursday.
That $200 million project will lower the mine to depths of nearly 9,000 feet. The new shaft will prolong the mine’s life and allow the company to access richer ore, Hecla officials have said.
The company said recently that the construction project is a little more than 40 percent complete and that it remains on time and on budget with an expected completion by the end of 2014.
The Lucky Friday ceased mining after Thursday’s accident while it was investigated, Hecla said.