The source of the poisonous gas, however, is under investigation. At a press conference Sunday night authorities said they were are looking at whether a small explosion in the mining process on Saturday might have been the source of the carbon monoxide.
The miners who were killed were identified as 34-year-old Nick Cappano of Montrose and Rick Williams, 59, of Durango. The other miners were expected to be OK, said Rory Williams, the operations manager for Denver-based Star Mine LLC.
"I knew both of these individuals personally," said Williams, who said he is no relation to Rick Williams. "They were hard-working men. They were great men. They will be remembered indeed."
Williams said all of the men are required to wear personal respirators and the two who died had them.
"As far as we can tell it doesn't appear to be an equipment malfunction," he said.
Williams said gas detectors are common on the site, and telephones link underground tunnels to the surface and other locations on the 34-acre site.
The Revenue-Virginius Mine, six miles south of Ouray, resumed operation this year at a historic site that produced silver from 1876 into the 1940s.
Star Mine received a permit from the state Feb. 5 to mine silver, gold and sulfides there. About 100 miners work at the...