DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
ACCIDENT INVESTIGATION REPORT
(Underground Coal Mine)
Fatal Rib Fall
Oak Grove Mine, I.D. No. 01-00851
U.S. Steel Mining Company, Incorporated
Adger, Jefferson County, Alabama
August 16, 1996
O. L. Jones
Coal Mine Safety and Health Inspector
Originating Office - Mine Safety and Health Administration
135 Gemini Circle, Suite 213, Birmingham, Alabama 35209
Michael J. Lawless, District Manager
The Oak Grove Mine is an underground coal mine operated by U. S. Steel Mining Company, Inc. The mine is located ten miles west of Concord, Jefferson County, Alabama, off Route 23. The mine opened in October 1972, and began production in May 1974, extracting coal from the Blue Creek coal seam which averages sixty (60) inches in height. The seam is at a depth of 1,091 feet.
The mine has six intake air shafts, one intake elevator air shaft, one material slope, one belt intake slope, and five return air shafts. The mine is ventilated by four (4) Joy H-120-65-D, 10-foot diameter exhaust fans, and one Jeffrey 8HU-117, 10-foot diameter exhaust fan with a total exhaust of 3.5 million cubic feet per minute (cfm).
The total methane liberation in a 24-hour period is approximately 12,000,000 cubic feet from exhaust fans, approximately 300,000 cubic feet from the degasification system, and 1,000,000 cubic feet through the vertical degasification system.
Roof support on development mining under normal roof conditions is 4-foot full resin grouted roof bolts on 5-foot centers with two (2) eight-foot full resin grouted roof bolts as supplementary support set between the rows.
A total of 436 persons are employed at this operation, with 401 underground personnel working three production shifts each day, five to six days per week with maintenance and repairs scheduled on weekends, as necessary. There are four (4) continuous mining machine sections on development driving longwall gate entries, and one (1) longwall section on retreat mining. Approximately 13,000 tons of coal are produced daily.
The last complete MSHA Safety and Health inspection was completed July 15, 1996. A regular MSHA Safety and Health inspection is presently being conducted which began on July 22, 1996.
Officials of U.S. Steel Mining Company, Incorporated are:
Ron Osborne.....................General Manager
Mike Sumpter....................General Mine Foreman
Marty Hayes......................General Maintenance Foreman
J.R. Nogosky.....................Manager of Safety
Danny Richardson...............Senior Underground Mining Engineer
The employees at the mine are represented by the United Mine Workers of America. The Chairman of the Health and Safety Committee is James Bell.
DESCRIPTION OF ACCIDENT
On Friday, August 16, 1996, at approximately 3:00 p.m., the Main North Section crew, under the supervision of J. T. Williams, Section Foreman, entered the mine via the elevator shaft. The crew traveled via portal bus from the shaft bottom to the section, arriving at approximately 3:45 p.m.
Upon arriving at the section, Williams conducted a safety meeting and assigned the crew their duties. Williams instructed J. T. Baker (victim) and T. C. Perry, Roof Bolters, to contact the day shift roof bolters to obtain information on where the roof bolting machine was located.
A section power center move was being planned and Williams went to the power center and met Robert Cunningham, Area Manager. They discussed the intended power center move. Cunningham left the section as his shift was completed. Williams then went to the No. 3 entry where overcast construction was in progress. There he met Kenneth Harbin, Continuous Mining Machine Helper, and Harvey Bryant, Continuous Mining Machine Operator, who were replacing worn cutter bits.
Harbin and Williams visually examined the brow and roof in the No. 3 entry and detected no sign of loose, unsupported brows or damaged roof bolt plates. Williams and Baker talked about the brow and roof and reportedly Baker said the brow looked stable. Williams asked Baker if he had enough roof bolting materials to complete the roof bolting of the area. Baker replied that he had sent a fellow employee for additional materials. Baker was in the process of preparing a drill steel. Williams then went one crosscut outby the overcast to check on conveyor chain adjustments needed on a shuttle car. At the time someone (unknown) yelled that the section belt conveyor was not operating. Williams went to the section telephone to call and find out why the section belt was not operating. While using the telephone Williams heard a thump or bump. This was approximately 4:20 p.m. Williams then went towards the face area and encountered Harbin at the section loading point. Harbin informed him that Baker had been hit by the falling brow.
Another section was working one crosscut away. Williams saw someone and yelled for help. Williams then ran to the section telephone and called the surface and informed Cunningham of the accident and that an ambulance was needed.
PHYSICAL FACTORS INVOLVED
- The mine roof was supported, as the section advanced, with 4
foot x 3/4 inch diameter full grouted resin roof bolts
installed on 5 foot centers. Two eight foot full grouted
resin roof bolts were installed between the rows. The 4
foot bolts were anchored in the Mary Lee Coal seam which
lies above a 24 inch layer of middleman rock.
- Drilling and blasting of the mine roof to gain sufficient
overcast height resulted in an area 12 feet high by 20 feet
wide and approximately 130 feet in length. Normal mined
height is 6 feet.
- The inby edge of the brow in the No. 3 entry was bolted with
two 8 foot full resin grouted roof bolts and a row of 4 foot
full resin grouted bolts.
- The brows of the overcast area were supported with a double
row of timbers prior to blasting. The west brow was
supported by these timbers during the investigation. The
timbers in the center of the entry had been dislodged at the
north brow, leaving timbers on the ribs of the entry.
- The timbers were removed from the south and east brows
during the clean up by the remote controlled continuous
- The brow that fell was approximately 14 feet long, 5 feet
wide, and 30 inches thick and broke in three sections.
- The section of brow that struck the victim was approximately
7 feet long, 5 feet wide and 20 inches thick.
- The roof bolting crew involved in the accident were normally
production roof bolters. It was the consensus of the
investigating party that all employees were properly trained
and well experienced to perform this work. Statements made
by employees interviewed indicated they were properly
trained and well experienced in the type of work being
performed. There were in excess of twenty overcasts that
had been constructed in this area of the mine.
The plan for rehabilitation of the roof and brows in the area of the overcast were as follows.
- Clean up the blasted material with the remote
controlled continuous mining machine from the south
approach in the No. 3 entry.
- Clean the blasted material towards the east approach.
Turn and clean the material towards the west approach
as far as possible without the ram car operator going
inby the second row of roof bolts outby the brow
located in the No. 3 entry.
- Bring the roof bolting machine in to the east approach
of the overcast area and install a double row of 8 foot
by 3/4 inch fully grouted resin bolts in the east brow.
- Install 4 foot mechanical roof bolts in the roof area
of the overcast where pre-drilled holes were located
and proceed toward the west approach.
- Install 4 foot mechanical bolts in the pre-drilled
holes inby to the west side of the intersection in the
No. 3 entry.
- Turn and install roof bolts in the north and south brows in the No. 3 entry with a double row of 8 foot by 3/4 inch full resin grouted roof bolts.
- Clean up the blasted material with the remote controlled continuous mining machine from the south approach in the No. 3 entry.
- The roof bolts being installed at the time of the accident
were 4 foot mechanically anchored roof bolts.
- The holes in which the mechanically anchored roof bolts were
being installed were pre-drilled prior to the blasting of
the overcast site.
- An examination conducted prior to work beginning in the area of the overcast revealed no evidence of the brow being loose or requiring additional support.
A fatal accident occurred when a brow rolled out while roof bolts were being installed in an overcast site. Visual examinations of the brow made prior to the accident did not detect the imminent condition.
- A 103-K Order Number 4478888 was issued to insure the safety of miners until the investigation was completed.
Respectfully submitted by:
O. L. Jones
Coal Mine Safety and Health Inspector
Michael J. Lawless
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