DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
ACCIDENT INVESTIGATION REPORT
(Underground Coal Mine)
Fatal Fall of Roof
Mettiki Mine (I. D. No. 18-00621)
Mettiki Coal Corporation
Oakland, Garrett County, Maryland
June 7, 1999
Chris A. Weaver, Mining Engineer (Ventilation)
William L. Sperry
Coal Mine Safety & Health Inspector (Electrical)
Michael A. Evanto, Geologist
Originating Office-Mine Safety and Health Administration
5012 Mountaineer Mall, Morgantown, West Virginia 26501
Timothy J. Thompson, District Manager
Mettiki Coal Corporation, Mettiki Mine, I. D. 18-00621, is located near Oakland in Garrett County, Maryland. The mine is accessed by 8 inclined drift openings into the Upper Freeport coal seam which ranges from 5 to 11 feet in thickness. Ventilation is provided by two main mine fans exhausting a total of 410,091 cubic feet of air per minute. During advance mining, face areas are ventilated using auxiliary fans, exhaust tubing and scrubber- equipped continuous mining machines. The immediate mine roof consists of gray shale to siltstone, sandstone or inter-bedded shales and sandstone known as "stackrock".
Employment is provided for 194 underground and 18 surface employees. The mine is operated three shifts per day, five days per week, producing 21,000 tons of raw coal per day from two continuous mining machine units and one longwall section. Coal is transported to the surface via belt conveyor. Diesel powered scoops, track haulage, and rubber tired equipment are utilized for transportation of materials and personnel at this mine.
The Roof Control Plan in effect at the time of the accident was approved by the Mine Safety and Health Administration on June 24, 1997. The Roof Control Plan requires the longwall shields be set to a minimum distance of four feet from the longwall face when persons are required to work or travel in the longwall face area.
The principal officers for the Mettiki Mine at the time of the accident were:
Vice President of Operations.............................................George C. Tichnell
Manager of Underground Operations................................Alan B. Smith
Manager of Human Resources & Safety............................Horace J. Theriot, III
An MSHA Safety and Health Inspection (AAA) was ongoing at the time of the accident. The previous Safety and Health Inspection was completed on March 31, 1999.
The Non-Fatal Days Lost (NFDL) incident rate during the previous quarter was 8.11 for underground mines nationwide and 3.74 for this mine.
DESCRIPTION OF ACCIDENT
On June 7, 1999, the afternoon shift crew of the Panel 28 Longwall Section was mining beneath a sandstone channel which had intruded into the coal seam near the headgate end of the face . Since the sandstone channel had intruded into the coal seam below the minimum mining height of the longwall equipment, the afternoon shift had to drill and blast sandstone from the face in front of shields 5 through 10. After shooting the sandstone, the afternoon shift proceeded to take two wedge cuts on the headgate side of the face which required mining through the firm roof rock and bottom rock at some locations. After completing the second wedge cut, the shearer was traveling toward the tailgate when delayed due to a broken hydraulic fitting. The time required to repair the hydraulic fitting was estimated to be 20 minutes.
The midnight shift longwall crew, composed of six persons and supervised by William A. Orndoff, entered the mine at the regularly scheduled start time of 10:00 p.m., on June 7, 1999. The crew traveled from the surface to the Panel 28 Longwall Section via a diesel-powered, rubber-tired vehicle. The hydraulic fitting had just been repaired and the afternoon shift shearer operator was in the process of continuing travel toward the tailgate with the shearer when the midnight crew arrived on the section at approximately 10:20 p.m. The headgate-side drum of the shearer was parked near shield 31 during the shift change.
Normally, the off-going crew members brief their on-coming counterparts as to any pertinent information that may be of assistance to the on-coming workers. Upon arrival on the longwall section, the midnight shift crew members began relieving the afternoon shift crew members.
Donald Bray, Afternoon Shift Supervisor, informed Orndoff, the on-coming supervisor, that the top between shields 5 and 10 had been hard and difficult to drill prior to it's shooting. Richard Everson, Afternoon Shift Shearer Operator, informed Roger Sisler (victim), Midnight Shift Shearer Operator, that he might need to check the cutting bits on the shearer. Gary Sisler, Midnight Shift Utility Man, proceeded to carry a supply of cutting bits from the end of the supply road to the stageloader. Swanee Masters, Midnight Shift Mechanic, proceeded to his tool box to obtain the tools normally required in the performance of his assigned maintenance duties. Masters began making preparations to service the shearer while the cutting bits were being changed. Roger Sisler and Theodore Friend, Midnight Shift Shield Support Operator, proceeded toward the shearer.
Orndoff was evaluating the status of the section and began measuring the air flow velocity near shield 10 as Roger Sisler (victim), and Friend arrived at the shearer near shield 31. Orndoff was expecting production to begin. However, Roger Sisler informed Orndoff, via the face communication system, that he was going to set bits. Orndoff, via the face communication system, then informed Virgil R. DeWitt, Stageloader Operator, to remove the power from the shearer and face conveyor. Orndoff was still in the process of conducting the ventilation examination near the headgate end of the face when Roger Sisler, via the face communication system, requested that the power remain on the shearer so that it could be setup for changing bits.
The shearer operator normally decides when and where routine tasks such as setting cutter bits and performing maintenance are to be performed. The operator then prepares the shearer by assuring that the cowls are rotated down and set onto the mine floor and that the drums are free to turn. Near the location where the shearer had been parked during shift change, the immediate shale roof had been cut out or had fallen out during previous mining due to discontinuities associated with the sandstone channel. This created areas between the stageloader and shield 26 in which the height of the face was up to 10 feet. Evidence indicated that Roger Sisler moved the shearer approximately 9.7 feet toward the tailgate and away from the area with greater face height. The shearer was setup for maintenance with the headgate side drum located at shield 33, approximately 185 feet from the stageloader, at face location 70+93. Roger Sisler then informed the stageloader operator to remove the power from the shearer and face conveyor.
Orndoff completed his examination near shield 10 by placing his initials and the date and the time of the examination in the area where the air velocity reading was obtained and proceeded toward the shearer. When Orndoff was near shield 20, Roger Sisler signaled Orndoff with his cap lamp. Orndoff, based on previous work experience with Roger Sisler, interpreted this signal as meaning that everything was "OK" at this location. Orndoff acknowledged with a signal by his cap lamp. Orndoff decided to take advantage of this non-production time to conduct further examinations in the headgate and outby areas. Orndoff then proceeded outby the stageloader to measure the quantity and quality of the air in the belt entry.
Gary Sisler, Utility Man, began carrying cutting bits from the stageloader to the shearer. Gary Sisler observed Roger Sisler changing the cutting bits on the headgate-side shearer drum. Gary Sisler was aware that this drum normally requires a large number of cutting bits to be replaced and that two persons facilitate manually turning of the headgate drum for cutting bit replacement. Gary Sisler then crossed into the face conveyor area to assist Roger Sisler. During this period (immediately prior to the accident), Friend was replacing cutting bits in the tailgate side drum near shield 39. Swanee Masters, Mechanic, was now at the shearer conducting maintenance checks and adding hydraulic oil to the shearer.
At approximately 10:40 p.m., Roger Sisler was changing bits while standing near the tip of shield 32. The immediate shale roof, including some coal face material, fell from between the face and shields 31 through 33, striking Roger Sisler and barely missing Gary Sisler. Masters was adding hydraulic oil to the shearer near shield 36 when he heard rock hit the shearer drum. Gary Sisler had bent over to pick up additional bits, facing away from Roger Sisler, when he heard rock fall. Gary Sisler then turned and observed Roger Sisler in a sitting position on the face conveyor with his back toward the shields and his head and neck concealed by a large rock. Gary Sisler then yelled that a man was covered up. Friend and Masters responded by going to the headgate drum area. Orndoff was measuring air flow in the belt entry outby the stageloader when he heard Gary Sisler yelling. Orndoff immediately proceeded toward the shearer, passing Friend who was going to get a slate bar to aid in the recovery. Orndoff, Masters, and Gary Sisler removed a rock, measuring approximately 2' x 4' x 1.3', from the victim's head and neck. Orndoff and Masters, Certified Emergency Medical Technicians (EMT's), immediately checked the victim for life signs. Only a very weak pulse was detected. No other positive vital signs were confirmed at this time. At this point, the victim legs were still trapped by another rock measuring approximately 5' x 1.6' x 1.1'. Orndoff then instructed Gary Sisler and Friend to move the shearer toward the tailgate to facilitate the recovery of the victim. Mark Carpenter and Rodney Fultz, both EMT's, arrived at the site approximately 10 to 15 minutes after the accident. A hand operated cable hoist was secured to shield 31 to remove the rock from the victim's legs. The victim was placed on a back board and transported to the headgate area.
Near the headgate area, EMT's attempted to revive the victim by utilizing an automatic external defibrillator. However, these efforts were unsuccessful.
The victim was then transported to the surface in a diesel-powered, rubber-tired vehicle. Attending EMT's continued lifesaving efforts to the surface. The victim was then transported by the Southern Garrett Rescue Squad to the Garrett County Memorial Hospital. The victim was pronounced dead at 12:05 a.m., on June 8, 1999, by Dr. Perry, attending physician.
PHYSICAL FACTORS INVOLVED IN THE ACCIDENTThe investigation revealed the following factors relevant to the occurrence:
- The Mettiki Mine Panel 28 Longwall Section was retreat mining the Upper Freeport coal
seam under approximately 650 feet of cover at the time of the accident.
- The Upper Freeport coal seam varied from 5 to 11 feet in thickness and contained up to three
shale binders in the vicinity of the Panel 28.
- The accident occurred at shield 32, approximately 180 feet from the headgate, at face location 70+93.
- The face of the Panel 28 Longwall Section was approximately 750 feet wide. Ground support
was provided with 133 MECO two leg 815 ton shields. The panel was being mined with a Joy
- The rock that forms the immediate roof over the Panel 28 Longwall Section, while varying,
was composed of gray shale to siltstone, sandstone or inter-bedded shales and sandstone known
locally as stackrock.
- The floor of the Panel 28 Longwall Section was composed of 1 to 19-feet of fireclay and/or
- The Panel 28 Longwall Section had encountered a sandstone channel in the roof above the
coal seam. This sandstone channel, present from 0 to 10 feet above the coal seam, was
composed of hard, massive, light gray to buff colored sandstone. Where the sandstone was not
directly on the coal seam, the immediate roof above the coal seam was a gray shale. The
sandstone channel crossed the longwall panel from the tailgate side, on an angle of
approximately 45 degrees, outby toward the headgate side of the panel. Primarily remaining
above the coal seam, the sandstone channel was approximately 2200 feet wide over the tailgate
entries and widened to 2900 feet over the headgate entries. At the time of the accident, the Panel 28 Longwall Section tailgate had just retreated past the sandstone channel and the headgate was projected to be beneath the channel for approximately another 1600 feet.
- Intrusions into the coal seam from this sandstone channel had been frequently encountered
during retreat mining of the Panel 28 Longwall Section. At the time of the accident,
approximately 43 feet of retreat mining remained before the headgate side of the panel would
have cleared the last anticipated intrusion of the sandstone channel into the coal seam.
- The sandstone channel was present directly on the coal seam at shields 5 through 10. Blasting was required to advance the longwall face on the afternoon shift prior to the accident.
- The immediate roof rock, 14 to 16 inches thick above the coal seam, at the accident site was
composed of gray shale exhibiting slickenside features. Immediately above the failed rock, a
thin layer of fireclay was present on the bottom of the sandstone channel. At the time of the
investigation, the gray shale between the face and shields 31 through 33 had fallen, revealing the bottom of the sandstone channel and the thin layer of fireclay.
- The Roof Control Plan in effect at the time of the accident, approved June 24, 1997, required
the longwall shields to be set to a minimum distance of four feet from the longwall face when
persons are required to work or travel between the shield tips and the face.
- During the investigation, the tip of shield 31 was approximately 16 inches below the roof
and the canopy was in contact with the roof above the legs. The tip of shield 31 was 41 inches
from the face.
- During the investigation, the tip of shield 32 was tight against the roof (with its tip angled up more steeply than the adjacent shields) and 39-inches from the face.
- During the investigation, the tip of shield 33 was approximately 14 inches below the roof
and the canopy was in contact with the roof near the legs. The tip of shield 33 was 36 inches
from the face.
- Mined height at the accident site was approximately 82 inches. The coal above the top
binder had pinched-out above shield 33 and the top binder graded into the gray shale above the
coal seam. The middle binder at the accident site was 12 to 18 inches thick and the coal above
the binder was 18 to 24 inches. The coal below the middle binder was at least 30 inches thick,
although coal and rock debris obscured the bottom portion of the mined height.
- The positive set-valves on shields 31 through 34 were in the active position. This would
raise the canopies of the shields until they contacted with the roof and the set pressure was
- A preshift examination of the Panel 28 Longwall Section was made between 9:01 p.m. and
9:14 p.m. for the oncoming midnight shift. The last cut from the face, in front of shields 31
through 33, was mined by the afternoon shift crew after the preshift examination and shortly
before 10:00 p.m. The brow which failed, resulting in the accident, was created at that time.
Coal was not mined by the midnight shift crew. They were in the process of changing bits on
both of the shearer drums at the time of the accident.
- At the time of the investigation, the headgate-side drum of the shearer was positioned in
front of shield 33 and the tailgate drum was positioned near shield 40. It was estimated that the shearer had been moved approximately 27 inches toward the tailgate immediately after the
- The victim's hat was found beneath the same rock which had covered his legs. This rock originated from directly in front of shield 32. The rock removed from over the victim's head and neck originated from between the face and shield 33 and contained both shale and coal face material.
The victim was positioned near the tip of shield 32 and was struck by rock from above and in front of shields 31 through 33. The immediate roof had fallen out during a previous mining pass resulting in a cavity over the canopies of shields 31 through 33. The last mining pass had created a brow of immediate roof rock between the face and just over the shield tips. This newly formed brow of gray shale was not extended sufficiently over the shield canopies to maintain support. The thin fireclay seam, located between the sandstone channel and the gray shale, provided no cohesion between the rock units. The gray shale directly above the coal seam contained slickensides (which reduced its spanning capability) and a fracture had formed along the junction of the face and the immediate roof. These conditions would not have presented a serious hazard to miners working on the walkway side of the panline and, apparently, were not perceived by the victim as presenting a hazard when choosing this location to change bits. This combination of factors resulted in large pieces of rock being dislodged from above and in front of shields 31 through 33 which fell without warning while miners were working near the shield tips. The large rocks pivoted and rolled under shield 32 and/or deflected off the headgate shearer drum and under shield 32.
The following orders/citations were issued due to conditions revealed during the investigation.
- A 103(k) Order (No. 7142379) was issued to ensure the safety of all persons in the mine until an investigation was completed and all areas and equipment were deemed safe.
- A 104(a) Citation (No. 7142380) was issued citing 30 CFR 75.202(a). The roof and face near the No. 32 Shield on the Panel 28 Longwall Section was not adequately supported or otherwise controlled to protect persons from hazards related to falls of roof or face where persons were changing bits near the shield tips. The immediate roof (consisting of 15-inch thick gray shale containing slickensides) between the face and the tip of shields 31 through 33 did not extend sufficiently over the shield canopies to maintain support of the material. Also, a thin fireclay seam, located between the immediate roof and the sandstone main roof, provided little or no cohesion between the rock units. The combination of these conditions caused large pieces of rock from above and in front of shields 31 through 33 to dislodge and pivot out into the work area beneath and in front of shield 32.
Chris A. Weaver
Mining Engineer (Ventilation)
William L. Sperry
Coal Mine Safety & Health Inspector (Electrical)
Michael A. Evanto
Timothy J. Thompson
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