Sunday, August 12, 2007

Rock-Pressure Bursts Impede Rescue Effort

Just got word via e-mail from Ellen Smith of Mine Safety and Health News that two "bounces" occurred overnight in the Crandall Canyon mine where rescuers are still struggling to reach 6 missing miners. Miners speak of a "bounce" or "bump" when coal bursts from the wall of the mine tunnel due to extreme rock pressures. These can happen during active production as well, and the flying coal has caused fatalities and injuries.

Both incidents reportedly interrupted the rescue efforts. Workers returned to the mine after each incident, Ellen reported. She said media have been waiting all day for an expected news briefing from MSHA.

The rescuers who continue to work in the face of further evidence of unstable ground are undertaking a significant personal risk in the hope of saving the missing miners, just like the teams who fought for days to reach 27 missing miners in the face of a December 1984 Utah mine fire.

At this point, fatigue is certain to be a factor -- among those managing the emergency as well as those physically working underground. In a protracted emergency, decision makers, technical personnel and miners all need to be rotated. In the heat of the event, it can be very hard to let go and allow back-up personnel to take charge for a time, but lack of rest can impede awareness, slow down responses and impair judgement. I hope decision-makers are managing the fatigue factor.

The Salt Lake Tribune reported that evidence indicates the original incident involved "floor heave" rather than a collapse of roof strata. Extreme rock pressures can actually squeeze mine floors upward.

The Tribune also reported ground control problems at the mine dating back to March and said it wasn't clear whether the mining company followed advice it sought from an engineering consultant.

Once the emergency is over, there will obviously be questions about MSHA's approval of the the roof control plan as well as whether the mine operator followed the plan as the agency approved it.


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