Four miners who were trapped and injured two years ago during a rock burst at the Lucky Friday Mine are suing Hecla Mining Co., alleging that mine managers knowingly sent them into unsafe working conditions. On Dec. 14, 2011, Ronnel E. Barrett, Gregg Hammerberg, Eric J. Tester and Matthew Williams were part of a team of seven miners sent to repair damage from an earlier rock burst when another occurred, according to the lawsuit. The sudden, violent failure of a supporting rock pillar trapped them 5,900 feet below the surface.