In its final investigative report released on Tuesday afternoon, the agency said 33-year-old crew leader Joseph Cassell was working at Rhino Eastern’s Eagle No. 1 operation in Bolt, Raleigh County, when he was fatally injured on June 27.

“The victim was in the process of cleaning the mine floor to install a wooden support timber, because of a deteriorated rib, when the accident occurred … a portion of the rib comprised of coal and rock fell and struck him,” the investigator said, adding the fallen material measured about 100 inches long, 32in in thickness and was 37in in height.

The accident occurred one crosscut out by the loading point of the mechanized mining unit 004 mining section.

“The installed 42-inch conventional rib bolts were inadequate to support, or otherwise control and protect persons from the hazard of falling material,” the agency said.

“A practice existed, which allowed miners to position themselves near hazardous overhanging broken ribs in order to install wooden posts.

“The mine operator did not provide adequate guidance or oversight to an inexperienced crew, which was assigned to hazardous job tasks.”

In its root cause analysis which pointed to both issues, MSHA investigators said the operator was ordered to revise its roof control plan and to obtain walkthrough roof bolting machines to install rib bolts from a safe location.

The mine plan now specifies five foot long fully grouted rib bolts and multiple rib bolts when the mining height exceeds seven feet.

Rhino Eastern was also given a copy of the agency’s enforcement policy for CFR 30, Section 75.400, which states that “loose coal ... shall be cleaned up and not permitted to accumulate in active workings”

Also, according to MSHA’s Program Policy manual regarding this requirement: “Experience has demonstrated that the loading of loose coal caused by sloughing ribs creates a hazardous condition in that the pillar size can be substantially reduced and the width of the entry or room dangerously increased, therefore, such loose coal shall not be considered accumulations of combustible material if such material is rendered inert by heavy applications of rock dust.

“However, such loose coal shall not be permitted to accumulate in the roadways or outby timberlines.”

The operator trained its entire staff in the policy requirements and documented the training.

Rhino received a 104(a) citation for a violation of 30 CFR section 75.202(a) for inadequate support or control of the rib areas.

Specifically, the investigators saw problem ribs from the 1B belt drive, extending 12 crosscuts to survey station 2726; from the 1B conveyor belt entry at survey station 2674, to the active mining section of MMU-004, a distance of six crosscuts; and adjacent areas near survey stations 2614, 2676, and 2673.

“The operator's attempts to support the ribs with timbers and/or 42-inch conventional bolts were inadequate, as evidenced by loose, broken and hanging ribs and broken supports at numerous locations,” MSHA said in the report.

“The presence of these hazardous conditions served to put the operator on notice that greater efforts were required to support the ribs in the affected areas.”

The Eagle No. 1 underground mine employs 88 underground coal miners and seven surface personnel, extracting coal from two active mining sections with one continuous mining machine on each section.

The operation produces about 250,000 clean tons of coal a year.

At the time of the accident, MSHA was in the process of completing the required E01 quarterly safety and health inspection.

The non-fatal injury incidence rate for the mine in 2010 was 4.51, versus the national rate of 3.17.