This morning’s session on Coal Bumps and Seismicity gave us some background to the Crandall Canyon disaster. Fisrt a magnificent presentation by J Whyatt on a review of case studies presented in 1958 at an SEM Bump Symposium. He re-read the papers from 1958 and noted that almost everything that happened in Utah had been noted and very-nearly predicted. If only those responsible for the Utah coal mine had bothered to read the 1958 SME papers, nine people would still be alive.
A. Ionnacchione of the University of Pittsburg noted from 1983 to 2007 we have had some 187 bump incidents at coal mines in Utah and he eastern coal fields that have resulted n 229 injuries and 19 fatalities. Again those at Crandall Canyon appear to have been sublimely ignorant of what was going on regarding coal bumps in the 25 years preceeding their event. Thus it is appropriate that the mining industry and NIOSH in particular revisited the 1958 wisdom and the recrd from 1983 onwards.
The impression one gets is that just as extreme floods and extreme economic swings, like the current times, coal mine bumps are statistical outliers, they have received less attention than the ordinary things that injure and kill people in mines. But with hindsight it is irresistible that we re-assess the causes and results of such statistical outliers. And try to find ways to stop more such incidences.
S. Harvey of Colorado School of Mines is researching ways to control bump-induced damage. It is not an easy issue, for the rock can come at you suddenly from all dierctions with a low probability of occurrence. S. Jarvey is looking at yielding support systems used in deep metal mines and trying to evaluate their applicability in coal mines subject to bumps. We must wish him success with his studies.
The researchers from the University of Utah reported on their efforts to pinpoint the causes and the timing of post August 6, 2007 seismic events at Crandall Canyon. I was impressed by what they found, but I would hate to be involved in using their findings in a court of law to convict those accussed of negligence and worse in running the mine and allowing the conditions that lead to so many deaths.
Regardless, it is impressive to see the intellect and effort now going into trying to unravel the science and technology of coal mine bumps. Let us hope it results in a more pessimistic assessment than the SME 1958 optimistic assessment that concluded that coal bumps were controllable and a thing of the past. For extreme statistics have a way of occurring and discombobulating us in embarrassing ways.