Independent Review of MSHA's Actions at Crandall Canyon Mine

Risk Analysis
1) The bounces that continued to occur during the rescue period. During any mine
emergency, the information that is available and that which is obtained through sampling,
measurements, communication, etc., must be continually compiled, trended, and evaluated to
determine the risk to the underground workers. For example, in the aftermath of an explosion,
mine gases are sampled, analyzed, and trended to determine if conditions are favorable for
subsequent explosions which would endanger rescue workers. If it is determined that
subsequent explosions were probable, the underground operations would be suspended until
actions could be taken which would mitigate the probability of subsequent explosions. The
data available for bounce events would be the frequency, severity, and location of subsequent
bounces as well as information from observations of personnel underground.
During the 10 days that the underground rescue attempt was ongoing at Crandall Canyon,
bounces continued to occur. On August 6 th , a bounce occurred in the Main West section where
a mine rescue team had breached a set of seals. The rescue team had been behind the seals,
came out, and was preparing to go back into the sealed area. If the team had been in the
sealed area when the bounce occurred, it is likely that they would have been injured. Early on
August 7 th , an MSHA inspector and company personnel were near the feeder in the No. 2
entry at crosscut 120. A bounce occurred in the No. 4 entry that refilled an area with rubble
similar to the amount which had been removed earlier. The inspector and company
employees were knocked down by the force of the bounce. Had they been in the No. 4 entry
when the bounce occurred, it is likely they would have been badly injured or killed. Several
other bounces occurred that were recorded in the logbook and described as covering the
continuous miner, creating thick dust, and requiring a head count to make sure everyone
could be accounted for.
Inspectors going underground were instructed to report significant events, including bounces
that occurred. However, they were never given instruction as to any specific circumstances
that would standardize the reporting. Since everyone had different levels of experience with
bounces, including many of the inspectors from the eastern MEU team who had no experience
with bounces, levels of reporting were not as consistent as they should have been.
Nevertheless, the lack of standardized reporting was irrelevant because none of the personsin-charge
thoroughly analyzed the bounce activity that was occurring. Davis stated that he
thought Technical Support Roof Control Division (RCD) personnel were analyzing the bounce
activity, but acknowledged that he never directed them to do so. The RCD personnel said they
never conducted such an analysis nor did they see one that was conducted by anyone else.
They were aware of company personnel collecting some seismic data, but did not know any
specifics about it. The RCD personnel further stated they suggested that someone look into
installing some seismographs so that a baseline could be developed to ascertain if there was
increased seismic activity as the advance continued. They stated Stickler advocated this idea,
but when it was determined that MSHA’s seismic equipment could not obtain the necessary
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