On Wednesday, June 29, 2011, at approximately 11:15 a.m., a 49 year old continuous haulage cable attendant was killed when he was struck by a section of rib. The rock was approximately 82 inches long, 36 inches wide, and 11 inches thick. The mining height at the accident site was just over seven feet, and the depth of cover was 700 feet.

Best Practices

• Conduct thorough pre-shift and on-shift examinations of the roof, face, and ribs immediately before working or traveling in an area, and thereafter as conditions warrant.
• Know and follow the Approved Roof Control Plan. Take additional measures to protect persons when hazards are encountered.
• Assure the Approved Roof Control Plan is suitable for prevailing geological conditions. Revise the plan if conditions change and the support system is not adequate to control the roof, face, and ribs.
• Rib bolts provide the best protection against rib falls and are most effective when installed on cycle and in a consistent pattern.
• Be alert to changing geological conditions which may affect roof, rib, and face conditions.
• Support loose ribs or roof adequately or scale down loose material before beginning work.

On Monday, June 27, 2011, a 33 year old miner was killed when a portion of coal and rock fell from the upper portion of a pillar rib. The material that fell was approximately 8 feet long, by 32 inches thick, by 3 feet high.

Best Practices

• Conduct a thorough visual examination of the roof, face, and ribs immediately before any work or travel is started in an area and thereafter as conditions warrant.
• Perform careful examinations of pillar corners, particularly where the angles are formed between entries and crosscuts are less than 90 degrees.
• Support any loose rib or roof material adequately or scale before beginning work.
• Take additional safety precautions when mining heights increase to prevent development of rib hazards.
• In areas prone to deterioration, install rib support when the area is mined initially.
• Be alert to changing geologic conditions which may affect roof/rib conditions.

On Thursday, July 29, 2010, at approximately 11:55 a.m., the left side integral roof bolter operator on a continuous mining machine was fatally injured. The victim was struck with a portion of rib measuring approximately 276 inches long by 55 inches high and up to 16 inches thick. The accident occurred while cutting an overcast. The victim had installed one test bolt and was near the left rear bumper of the machine, when the accident occurred. The rock in the left rib sheared off pinning, the victim against the machine.

• Develop a plan for cutting overcasts and train miners in the procedures and precautions.
• Examine the roof and ribs frequently while working.
• Take down or support any loose ribs or roof adequately before working or traveling in the affected area.
• Be aware of changing roof and rib conditions, especially when working between the ribs and equipment.
• Unless necessary, do not position yourself between any piece of machinery and the rib.
• Where the mining process allows, remain within the confines of protective devices such as cabs, canopies and rib protectors whenever possible.
• Install additional rib support prior to mining in areas where the roof or floor is cut above or below the coal seam, especially overcasts, loading points, etc.

Click here for: MSHA Preliminary Report (pdf), MSHA Investigation Report (pdf)