Section foreman Jeremy Sigler, 34, who had 10 years of mining experience, was killed March 10 when a large section of rib rolled out of the right side of the number 2 entry at the Kingston No. 2 mine in Scarbro, Fayette County, which was being developed on the Number 1 section.
“The victim was operating the section's left-side continuous mining machine at the time of the accident,” the US Mine Safety and Health Administration said in its final investigation report, confirming the rib portion that struck Sigler measured 6 feet 7 inches long, 40in wide and varied in thickness from 1in to 10in.
The agency estimated that the rock, which struck the victim as he was mining an extended depth cut in the No. 2 entry, weighed as much as 1800 pounds.
Investigators said no violations or hazardous conditions had been reported for the pre-shift examination of the Number 1 section the day of the fatality, and that Sigler had signed the pre-shift examination record.
In its probe of the southern West Virginia accident scene, federal officials found the mine had exceeded the approved cut depth outlined in its methane and dust control plan for MMU-004.
That documentation instructed a maximum distance of 20 feet from the end of the line curtain to the deepest point of penetration.
Because the additional time involved with mining the deeper cut increased the victim's exposure to a hazardous rib condition in the number 2 entry, MSHA said the move contributed to the fatal accident.
“The hazardous rib conditions on the Number 1 section were obvious, extensive and had existed for the last eight crosscuts,” investigators said.
“In the active face area, hazardous rib conditions existed inby the last open crosscut on the right side of entries Numbers 1, 2, 3, 6, and 8. No rib supports of any type were installed for these hazardous ribs.”
Also, in the last open crosscut as well as one crosscut outby, officials found the right-side ribs and the outby rib contained hazardous rib conditions in the 1 through 9 entries.
A review of the rib control and support conditions at Kingston revealed severely deteriorated ribs in the panel being mined at the time of the accident and generally in all locations exceeding 1000ft of cover.
“The only method of rib support that the operator had in place at the mine was to pull down any bad ribs that were observed and to set timbers along these bad ribs,” MSHA said.
“However, timbers were not installed inby the last open crosscut at the time of the accident. The mine did not have a systematic method of placing timbers based on overburden depth, nor did they have a method in place to deal with bad ribs inby the last open crosscut or close to the face area.”
The timbers that had been set were inadequate to protect workers from the type of rib falls the mine was suffering.
“The operator only reacted to bad rib conditions and at no time developed or implemented a method of prevention,” officials said.
It also confirmed that an earlier rib fall accident had occurred in the Number 1 section of the mine in January of this year.
In that incident, a piece of rib rolled out, striking the continuous mining machine operator on the foot.
The operator was left with a metatarsal fracture but the Kingston Mining did not revise the mine’s roof control plan post-incident.
MSHA concluded that a myriad of operator shortfalls worked in tandem to contribute to the fatal incident.
“The mine operator failed to develop and implement a method of rib support for mining under deep cover which prevented hazardous rib rolls,” investigators said.
“The obvious hazardous conditions due to falling rib material were extensive during the development of the Number 1 Section, for a distance of 640 feet. Mine management took insufficient actions to prevent the existence of hazardous rib conditions and allowed miners to be exposed to the hazardous conditions for an extensive period of time on the Number 1 Section [and] mine management performed inadequate examinations and failed to recognize the seriousness of the hazards present on the section.”
To rectify the issues, the agency ordered the operator to develop a mining plan that included rib bolting when mining in excess of 1000ft.
The plan also involves changes to the mine’s roof control plan as well as the acquisition of roof bolting machines that can install horizontal rib bolts.
Kingston’s plan requires systematic actions to control pillar corners when mining between under 700ft to 1000ft.
MSHA also ordered the operator complete a written policy regarding preshift examinations and training of all examiners in the recognition of mine hazards has been conducted.
In its enforcement actions, federal officials issued a Section 104(d) citation for a violation of 30 CFR 75.202(a) for its failure to protect workers from rib fall hazards.
“This violation is an unwarrantable failure to comply with a mandatory standard,” it said.
“Standard 75.202(a) was cited 21 times in two years at mine 4608932.”
Additionally, it issued a Section 104(d)(1) order for a violation of 30 CFR 75.370(a)(1) due to the mine’s failure to follow its approved ventilation plan.
Again, investigators said the violation was an unwarrantable failure to comply with a mandatory standard.
“Standard 75.370(a)(1) was cited 21 times in two years at mine 4608932,” it confirmed, all of which were to the operator.
An unwarrantable failure order was issued to Kingston Mining under Section 104(d)(1) for a violation of 30 CFR 75.363(a) because the mine did not post danger signs or correct areas with existing hazardous conditions.
The agency said the operator had a violation of an unwarrantable failure to comply with a mandatory standard, failing to exercise a high standard of care, in the 104(d) order for a violation of 30 CFR 75.223(a)(1).
“The operator is required to propose changes to the roof control plan when conditions indicate that the current plan is not suitable for controlling the roof, face and ribs of the mine,” it said. “Revisions to the roof control plan were not proposed by the operator when conditions indicated that the roof control plan did not control the ribs as required.”
Kingston received an unwarrantable failure order under Section 104(d)(1) for a violation of 30 CFR 75.360(b)(3) stemming from an inadequate preshift examination conducted for the evening shift.
The Kingston Number 2 room and pillar mine is operated by Kingston Mining, a subsidiary of Alpha Natural Resources.
The mine employs 95 people, 91 underground, and produces an average 8,700 tons of raw material a day.
MSHA had completed its last regular inspection of the mine on December 20, 2011.
Kingston’s Non-Fatal Days Lost (NFDL) injury incidence rate during the period of January through December 2011 was 3.28, versus the national rate