January 7, 2012
Stand on Firm Ground
Take steps to make sure ground conditions are stable before entering the work area.
The accident: On June 20, 2009, a 52-year-old miner with 25 years of experience was fatally injured while washing a face drill. He and a second miner were washing the unit when they heard popping sounds. The second miner said they thought the noise was coming from the elevated boom on the drill as the hydraulics bled off. The second miner reported then hearing two loud noises and feeling a rush of air. When he turned around, the roof had fallen, burying the first miner, the drill, and other equipment. The first miner was pronounced dead when his body was recovered and brought to the surface. His death was attributed to crushing injuries.
The bottom line: The accident occurred because the ground support system for the mine was not adequately designed, installed, and maintained to control the ground where miners worked and traveled. The roof rock broke below the anchorage zone of the roof bolts and pulled several of them out of the roof, leaving the expansion shells in the bolt holes. The fallen roof was about 50 feet long by 20 feet wide and up to 3 feet thick.
The applicable standard
30 CFR § 57.3360
Ground support use.
Scaling and Support — Underground Only
Ground support shall be used where ground conditions, or mining experience in similar ground conditions in the mine, indicate that it is necessary. When ground support is necessary, the support system shall be designed, installed, and maintained to control the ground in places where persons work or travel in performing their assigned tasks. Damaged, loosened, or dislodged timber used for ground support which creates a hazard to persons shall be repaired or replaced prior to any work or travel in the affected area. AM
• Design, install, and maintain a support system to control the ground in places where persons work or travel.
• Examine and test ground conditions in areas where work is to be performed prior to work commencing and as ground conditions warrant during the shift.
• Be alert to any change of ground conditions.
• Identify and scale loose ground from a location which will not expose persons to falling material.