MSHA News Release
MSHA focuses spotlight on rib control in light of recent coal mining fatalities
Top risk factors are mining height and depth of cover
ARLINGTON, Va. — The U.S. Department of Labor’s Mine Safety and Health Administration today announced that the focus of this year’s Preventive Roof/Rib Outreach Program is on improved mine rib control. In 2010, there were three rib fall fatalities and two roof falls that killed three miners. In addition, two miners have died so far this year as a result of underground rib failures.
“While recent trends have shown a decline in roof fall fatalities, the incidence of rib fall deaths has remained nearly constant,” said Joseph A. Main, assistant secretary of labor for mine safety and health. “Furthermore, approximately 100 miners are injured by rib falls every year, due in large part to the rise in mining heights underground.”
Roof control in underground mines involves securing the top as well as the sides of travel ways, or walls, which are referred to as “ribs” in underground mines. A detailed study of 22 of the 24 rib fall fatalities that have occurred since 1995 indicates that the two greatest risk factors are mining height and depth of cover. Today, many mines are located in coal reserves that previously were avoided due to poor roof conditions. These mines frequently are deeper and may have abandoned mines above and/or below them, which often exert additional stress on the roof and ribs.
Other risk factors include multiple seam interactions, rock partings in the seam and retreat mining. Joints or slickenside (smooth-surfaced) geologic features that dismember the rib increase risk. Approximately three-quarters of rib fatality victims since 1995 were roof bolting and continuous mining machine operators.
“Over the past few decades, improvements in roof control technology such as new bolting systems, automated temporary roof support systems, use of cabs and canopies, and mobile roof supports have led to a significant reduction in roof/rib fall fatalities,” said Main. “Through PROP, we hope to increase mine operators’ awareness about the hazards and precautions necessary to prevent such accidents.”
“Coal Mine Rib Control for Mine Operators,” a recently developed MSHA brochure, points out key trends in recent roof and rib accidents, and provides safety advice and tips for mine operators to consider in maintaining proper roof and rib control. Inspectors will deliver this publication and other educational materials to underground mines, and mine operators will receive an alert on the hazards and actions needed to prevent accidents.
Last month, MSHA kicked off its 2011 PROP effort with a roof control seminar at the National Mine Health and Safety Academy near Beckley, W.Va. Participants received information on rib failure issues, as well as important reminders concerning the effects of hotter weather and humidity, which increase chances of roof fall accidents. In April, the agency issued a program information bulletin discussing conditions that contribute to rib fall hazards and suggested methods for protecting miners from such falls.
More information about PROP is available at http://www.msha.gov.