As of 1:00 pm EST on 4/19, no information about the incident appears on the federal Mine Safety and Health Administration's website; the mine operator Hecla Mining provides updates on its homepage. Falls of ground are not uncommon in the Lucky Friday mine. According to incident reports available on MSHA's website, on March 4 a 10'X8'X6′ slab of rock fell in an area where miners were working, but no one was injured. In November, a rockburst occurred while workers were blasting and it released material covering a 6'X14'X8′ area and blocked an underground roadway. Three more rockbursts occurred in August and September 2010, again with no injuries. Rock bursts are like an explosion of rock, and occur as pressure builds in the strata. In mining regions with deep hardrock mines, operators can monitor pressure and can destress the pressure with drill holes and other techniques.