A fire inside the Lucky Friday Mine last month likely was set by an arsonist, according to the Shoshone County Sheriff’s Office.
About 170 miners who were working in the shaft where the fire was detected on July 26 are being scheduled for polygraph tests, Sgt. Detective Jeannette Woodard-Ochoa said Friday.
An investigator from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives recently reported his findings to the Sheriff’s Office, which is investigating the fire along with the mine’s owner, Hecla Mining Co., the Idaho fire marshal’s office and the federal Mining Safety and Health Administration, Woodard-Ochoa said.
ATF “determined they believe it is arson,” Woodard-Ochoa said.
ATF has not released an official finding on the fire, a Seattle-based spokeswoman for the agency said Friday.
A Hecla spokeswoman said she had “not been made aware” of the ATF investigator’s findings.
A second, smaller fire discovered in the silver mine earlier last month also is under investigation, officials have said.
On July 26, miners working on the 4900 level of the Lucky Friday were evacuated when the fire was detected, the company said. No one was injured. Three mine rescue teams monitored the fire and prevented it from spreading beyond the 4900 level; it was extinguished the next day.
Hecla is the largest silver producer in the U.S. The Coeur d’Alene-based company announced earlier this week that it will expand the Lucky Friday, near Mullan, Idaho, to extend its life by more than 20 years and boost production by 2 million ounces of silver per year.
Idaho’s Silver Valley was the site of one of the deadliest hard-rock mine disasters in U.S. history. Ninety-one men died in the Sunshine Mine fire on May 2, 1972. The fire led to a number of safety reforms, including the requirement that underground workers carry self-rescue respirators, which allow them to breathe when the air is contaminated with carbon monoxide.