Miner Travis Brock, 29, was killed the morning of January 22 at Bledsoe Coal’s Abner Branch Rider mine after a rib roll caused massive rib rock to pin him to the mine floor.

The victim, who had 10 years of experience, had been trimming and cleaning the mine floor with a Joy 12CM remove control unit in a bolted crosscut when the accident occurred, federal investigators said.

The fallen rock broke into several pieces, and MSHA estimated its pre-break weight at 9.3 tons. The total size measured about 82 inches high, 66in long and 108in wide.

As part of its investigation, the agency conducted an analysis of retreat mining pillar stability, or ARMPS, of the 8 Mains area.

That test indicated a pillar stability factor of 0.83 beneath the 820 feet of overburden, a factor that does not meet the recommended PSF of 1.33 by the National Institute for Occupational Safety and Health.

MSHA also found that a pre-shift examination conducted in the area did not identify any specific rib or roof conditions that would be considered hazardous, nor did the individual record any corrective actions for rib and roof conditions.

“The examiner either ignored or did not recognize the hazardous rib conditions, because the day shift crew was directed to proceed underground to begin production without hazardous conditions being recorded or corrective actions taken,” investigators said.

However, a federal review did reveal “numerous” hazardous conditions at the time of the pre-shift exam, including several locations with loose coal/rock ribs on the 001 MMU as well as violations of the mine’s approved roof control plan at multiple locations.

“The maximum allowable entry width of the pillar shears was exceeded in two locations, creating excessive intersection widths,” the review said.

“Roof support materials were not installed in accordance with the manufacturer’s recommendations; channel straps were installed over cracks and draw rock without using the correct bearing plates.

“The #2 heading at #33 crosscut was not bolted completely along the left rib [and] six separate locations were identified as violations of the approved roof control plan.”

MSHA also examined training records at Abner Branch, and found no deficiencies for Brock or any other company employee.

“This fatal accident occurred because the operator failed to support the rib on the 001 MMU to protect the miner,” MSHA concluded in its investigative report.

“Additionally, the operator failed to conduct adequate pre-shift and on-shift examinations and ignored the hazardous rib conditions on the 001 MMU. And, the operator failed to change its roof control plan to address the changing geological conditions which occurred on the 001 MMU.”

To rectify the root causes, federal officials ordered the hazardous rib conditions be corrected, and that the operator conduct and document a safety meeting with all employees on proper identification of unsafe conditions.

Additionally, Bledsoe Coal put in place a new policy of posting findings of pre-shift examinations so that their findings could be readily observed by miners before entering the mine.

Finally, the operator developed and submitted a revision to its roof control plan, which was subsequently approved by MSHA.

“The revision states actions that will be taken to support rib conditions in various heights and geological conditions,” the agency said.

“Fletcher twin-head, walk-thru roof bolters with rib-bolting capacity have also been installed.”

Federal officials issued four citations against Bledsoe, a subsidiary of James River Coal, as a result of its investigation. No monetary amounts attached to the violations were detailed by MSHA in its report.

The citations are in addition to those issued by the Kentucky Office of Mine Safety and Licensing against Bledsoe Coal, which released its findings in March.

The Abner Branch Rider underground mine in Leslie County, Kentucky, extracts from the Hazard No. 4 Rider seam. The continuous miner operation’s 60 employees access the mine via four drift openings.

The mine’s non-fatal days lost injury incidence rate through the third quarter of 2009 was 3.90, compared with the national NFDL of 4.12.