Seven men trapped underground for 24 hours are greeted by family members as they emerge from the mine.

Federal investigators have just announced that they cited Cobra Resources LLC for violations that contributed to an underground mine flood that trapped 7 workers for nearly 24 hours last May in Mingo County, W.Va.

According to a U.S. Mine Safety and Health Administration news release, inspectors cited Cobra (a subsidiary of Alpha Natural Resources) with two violations:

In the first violation, the mine operator did not regularly monitor and properly maintain the mine’s system of diversion ditches, designed to route storm runoff surface water away from the mine portals and into ponds constructed to handle runoff. Consequently, the operator failed to adequately protect the surface openings at the main portal areas to prevent flood water from entering the mine, in that flood waters from the surface entered the mine and inundated the escapeways, making those escapeways impassable.

The second violation was issued for the operator’s failure to maintain the two separate and distinct escapeways in safe condition. The flood waters entered the mine and inundated a low area at the main portal in all 10 entries, preventing the seven miners form exiting the mine. The depth of the water ranged from 0 feet to approximately 9 feet deep and was roofed in most areas.

An MSHA photo shows culverts at the mine portal.

In its investigation report, MSHA outlined these conclusions:

The accident occurred because storm runoff water entered the mine portals after being diverted when culverts underneath the portals were blocked by debris, mud, and rock, caused by scouring and erosion from a mud slide. The slide prevented water flow through the culverts, which caused the water to back up and enter the mine. Another factor that contributed to the accident was the inability of the mine’s system of diversion ditches to handle the storm water flow, as designed. The diversion ditches were not maintained or kept cleared of sediment, rocks, or vegetation, such as trees and underbrush. This allowed the runoff water to overtop the diversion ditches, flooding surface areas above the mine portals. The mine’s escapeways were blocked when the surface water entered the mine, preventing seven miners from exiting the mine and entrapping them for approximately 24 hours.

MSHA listed two “root causes” for this near-disaster:

— The mine operator did not regularly monitor and properly maintain the mine’s system of diversion ditches, designed to route storm runoff surface water away from the mine portals and into ponds constructed to handle runoff.

— The mine operator failed to monitor the portals of the underground mine where storm runoff surface water entered the portals, accumulated in a low area in the mine and blocked the primary and alternate escapeways.

MSHA chief Joe Main said:

These miners had the wherewithal to move to higher ground. Their actions, along with the expertise of federal and state mining officials and mine management, resulted in a positive outcome. Nevertheless, the mine operator’s failure to properly maintain underground diversion systems and escapeways could just as easily have ended in tragedy.

This accident underscores the need for mine operators to always maintain escapeways so they are available for use by miners when they need them.

MSHA has also posted a video about this event.