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Christopher Mark, Ph.D., P.E.

Mine Safety & Health Administration (MSHA)


The Road to Zero: The Fifty-Year Effort to Eliminate Roof Fall Fatalities from US Underground Coal Mines


Sixty years ago underground coal mining was the most hazardous job in the United States.  Roof falls were a big part of the problem.  They killed about 100 miners every year, more than all other causes put together.  Fast forward half a century to 2016, and the first year ever with zero roof fall fatalities.  Just three miners were killed by roof falls during the following six years. How was this historic goal achieved?  This presentation will start with a modern analysis of the causes of the roof fall fatalities in 1968.  Then it follows the reductions over time by category, using snapshots of the fatalities occurring in subsequent decades.  Along the way it evaluates the influence of the regulatory environment, changing mining methods, and better ground control technology.  The paper shows that in 1968 more than half of roof fall fatalities at large mines were attributable to an inadequate safety culture. The immediate effect of the 1969 Coal Mine Health and Safety Act was to reduce the riskiest activities, like needlessly going under unsupported roof.  Other hazards, like large roof falls, required technological developments before they were brought under control.  Roof Control Plans, which the US Bureau of Mines had been advocating since the 1920’s, also played a significant role throughout the process.  With fatal roof falls largely eliminated, current efforts are focused on preventing fatal rib falls, which in recent years have remained stubbornly high.  Continuing to reduce the numbers of non-fatal ground fall injuries and large, non-injury roof falls are also priorities.


Dr. Christopher Mark is internationally recognized as one of the world’s leading authorities on ground control for underground coal mines.  He began his coal mining career in 1976 as an underground miner, and completed his doctorate in mining engineering in 1987.  For the next 25 years he led the ground control research program at NIOSH, where he developed a number of engineering methods that are used around the world to design safer coal mines.  Currently Dr. Mark serves as the Principal Roof Control Specialist for the MSHA, providing expert guidance and developing program policy in a broad range of areas related ground control.  During his career his studies have taken him into more than 300 underground coal mines on six continents.  He has received numerous awards in recognition of his contributions to mine safety, including the 2012 SME Pittsburgh Section Distinguished Member Award and the 2008 PCMIA Donald S. Kingery Memorial Award.

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