By Kim Smiley

Around 3 pm on April 5, 2010 in Montcoal, West Virginia, a huge explosion rocked the Upper Big Branch South mine owned by Massey Energy Company.  At least 25 miners were killed, both from the explosion itself and suffocation caused by high levels of dangerous gases.

There are still 4 miners missing.  The missing miners were working farther back in the mine and the hope is that they were able to reach one of the airtight chambers stocked with enough food, water and oxygen for several days.  Rescue efforts are underway and drilling efforts are ongoing to add additional ventilation so that the gas levels can be reduced to safe levels to allow rescue workers to enter the mine.

This is the worst mine accident in the US in over 20 years. If the 4 missing miners are not found alive, this accident will have the highest number of fatalities since a 1970 mine killed 38 in Hyden, Kentucky.

What triggered this explosion is not known at this time, but both state and federal agencies have initiated investigations.

Even though many details are still unknown, a root cause analysis can be started by building an initial Cause Map.  There was an explosion which means there must have been an ignition source, flammable material and oxygen present.

The source of the flammable material is known since there were high methane gas levels in the mine.  Methane gas is naturally occurring in coal mines and must be continually vented.  It can also be assumed that the mine ventilation was inadequate for some reason since the gas levels built up.  Coal dust accumulation may have also contributed to the accident since powdered combustible material in an enclosed space is a very explosive combination.

The source of the spark that ignited the explosion is still unknown.

More information will become available as the investigation proceeds and a more detailed Cause Map can be built as additional causes are added.

Media reports about the accident have discussed past safety violations cited at the mine, but it won’t be clear if the accident was preventable until the investigation is completed.  What is known that in March 2010, the Mine Safety and Health Administration cited the Upper Big Branch mine for 53 safety violations.  In additional to the recent citations, there was also a troubling increasing trend in citations, which more than doubled between 2008 and 2009.

Hopefully, the information obtained during the investigation will provide useful lessons learned that can be implemented to prevent a similar accident in the future.