Miners freed after being trapped in Idaho mine

(CNN) -- A rock burst at a mine in northern Idaho Wednesday evening injured seven miners, a company spokeswoman said.

The incident happened more than a mile underground at the Lucky Friday Mine in Mullan, according to Melanie Hennessey, a company vice president. Twenty-five miners were in the area at the time, she said.

There was no immediate word on the conditions of the injured miners.

The Global InfoMine website describes a rock burst as "an explosive failure of rock which occurs when very high stress concentrations are induced around underground openings."

The Lucky Friday is a deep underground silver, lead, and zinc mine, according to its website.