`A |$oROG-Ntn+t)v7n\nX&\_aBC`xA!_5rw:}-kWw>7}or. The initial explosion was suspected to have emanated from a dynamite magazine. The mine failed to notify MSHA of the early danger signs, instead alerting the more industry-friendly Bureau of Land Management, when pillars started unexpectedly collapsing in March 2007.  The hole was fitted with a steel pipe to allow air samples to be recovered and a microphone to be lowered, which reached the cavity location underground early Friday morning on August 10.  In addition, a practice referred to as retreat mining was being conducted in some portions of the mine in which the coal had been removed by room and pillar method. Seismic waves from the "coal mine bump" (collapse) were reported as magnitude 3.9 to 4.0 by seismograph stations in Utah and Nevada. The disaster was the result of a coaldust explosion which swept through the mine. He recommends that a criminal investigation be conducted. This is Aalto. Please update your bookmarks. It has received 3 citation(s) till now. "There was zero void. 10 Years Later, Remembering One Of The Nation's Worst Mine Disasters.