The US Mine Safety and Health Administration released its final findings on the July 29, 2010 death of continuous mining machine-mounted roof bolter operator Jesse Adkins, 39, in a rib roll accident at Consol Energy’s Loveridge No. 22 operation.
“The crew had just started cutting the top portion of the 18D belt overcast between the No. 6 and No. 7 entries [and] the integral roof bolter operators were standing at their respective roof bolting stations along the sides of the continuous mining machine waiting to install the next roof strap,” the agency said.
“The continuous miner operator undercut the face, backed up and just started cutting the top when he noticed Adkins' light move. The continuous miner operator stopped the machine and walked around to the back side where he found the victim pinned between the machine and a section of rock rib measuring 193 inches long by 55 inches high and up to 16 inches thick.”
According to investigators, the rib failure was defined by a system of curvilinear, meandering slickensides running almost parallel with the trench rib and dipped steeply. In its report, MSHA noted that it appeared the slickensides had allowed the upper gray claystone and some underlying coal/shale/claystone to detach and fall against the CM unit and the victim.
The agency’s review of the pre-shift and onshift examination records did not indicate that adverse roof or rib conditions had been encountered by crews or made known to pre-shift examiners or management.
Finally, Adkins’ training records were found to be up to date, with annual refresher training having been completed in March 2010.
“The accident was caused by a failure to effectively control the rib at the work area which exposed the victim to a hazardous condition,” MSHA concluded in its report.
“The hazardous condition consisted of slickensides that were present in the out-of-seam area of the belt overcast between the No. 4 and No. 7 entries. Contributing to the accident was an inadequate rib support system, the use of equipment that was not provided with a means to support the ribs as mining advanced, and failure to re-evaluate changing conditions relative to equipment, mining procedures and practices.”
To rectify the issues, the agency ordered the revision of the mine’s approved roof control plan to include rib bolting as mining advanced in out-of-seam areas (18 inches above or below the coal seam).
Rib drills were also retrofitted to the continuous mining machine to install rib bolts with the advancement of mining.
Consol received a citation for a violation of 30 CFR, 75.202(a), 104(a) for low negligence as the left side rib line of the 18D belt trench/overcast on the No. 9 South Mains section was not adequately supported or controlled to protect from fall hazards.
The Loveridge No. 22 mine in Marion County employees 640 people, 583 of them underground. It produces about 6 million tons of coal annually from four continuous miner units and one longwall unit in the Pittsburgh No. 8 seam.
The operation’s non-fatal days lost incidence rate in 2009 was 2.9, versus the national average of 3.74.