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UNITED STATES
DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION

District 2

ACCIDENT INVESTIGATION REPORT
(Underground Coal Mine)

Sarah Mine
(I.D. No. 36-08571)
Penn Coal Company
Jennerstown, Somerset County, Pennsylvania
July 15, 1997

by

William D. Sparvieri, Jr.
Coal Mine Safety and Health Inspector

George J. Karabin
Supervisory Civil Engineer
Pittsburgh Safety and Health Technology Center

Michael A. Evanto
Geologist
Pittsburgh Safety and Health Technology Center

Thomas H. Devault
Coal Mine Safety and Health Inspector


Originating Office - Mine Safety and Health Administration
RR1, Box 736, Hunker, Pennsylvania 15639
Joseph J. Garcia, District Manager



GENERAL INFORMATION



The Sarah mine, operated by Penn Coal Inc., is located along State Route 4027, west of Jennerstown in Jenner Township, Somerset County, Pennsylvania. The mine is opened by three drifts into the Upper Kittanning coalbed which averages 84 inches in height. Employment is provided for thirty-three underground and four surface employees. The mine works two production shifts and one maintenance shift, five days a week. One continuous-mining machine section produces an average of 1,050 tons of coal a day. Coal is transported from the face by shuttle cars and discharged onto a belt conveyor. The belt conveyor transports the coal to the surface. Ventilation is induced by one exhaust fan located on the surface. During the last quarter, the mine did not liberate methane.

The principal officers of the operation are as follows:

William D. Renton..............................President
James T. Arnone................................Secretary/Managing Partner
Craig Hamilton...................................Superintendent/Mine Foreman
Paul Pelesky.......................................Safety Director


The last Mine Safety and Health Administration (MSHA) regular safety and health inspection was completed on June 9, 1997.

DESCRIPTION OF ACCIDENT



On Tuesday, July 15, 1997, at approximately 2:30 p.m., the South Mains section crew, under the supervision of James Faidley, section foreman, entered the mine and traveled to the working section. Upon arrival on the section, the afternoon shift crew relieved the day shift crew who had just completed mining a cut of coal in the crosscut being mined from No. 2 to No. 3 room. Scott Mostoller, day shift section foreman, told Faidley that only 10 to 15-foot deep cuts were mined on day shift. Joseph Molesky, continuous-mining machine operator, was instructed by Faidley to cleanup the last cut mined by day shift, move the radio remote controlled continuous-mining machine and prepare to mine the crosscut between No. 2 and No. 1 rooms. Molesky loaded the loose coal and rock while Faidley checked a water pump located in the return. After completing the cleanup, Molesky and Robert Koval, continuous-mining machine helper, backed the mining machine out of the crosscut between No. 2 and No. 3 rooms and positioned it to start the crosscut between No. 2 and No. 1 rooms. Faidley returned to the continuous-mining machine and instructed Molesky to mine only a couple of cars so the condition of the roof could be evaluated. Molesky started mining at approximately 3:45 p.m. and mined two shuttle cars of coal from the crosscut. After the second car of coal was loaded, approximately 10 to 12 inches of rock fell from the newly exposed roof. Faidley told Molesky to stop mining the crosscut and clean up the loose material so the exposed roof could be bolted. Molesky repositioned the continuous-mining machine to clean up the loose material. Molesky and Faidley walked along the right side of the continuous-mining machine tail and positioned themselves just inby the bumper of the machine.

At approximately 4:00 p.m., while waiting for the shuttle car, Molesky and Faidley heard a "ping" sound that seemed to originate at or near the face. As the shuttle car approached the tail of the continuous-mining machine, Faidley told Molesky to clean up and move out the continuous-mining machine. Molesky was just about to start the continuous-mining machine when he looked towards the newly mined face and saw the roof starting to ripple. He immediately turned and ran outby assuming Faidley was doing the same. Molesky had only traveled a few feet when the entire intersection fell, knocking him to the mine floor and covering him with rock. Richard Faidley, shuttle car operator, exited the operator's compartment of the shuttle car and yelled for help. Randy Ludwig, scoop operator, arrived and found Molesky partially covered with rock. While removing the rock from Molesky, Ludwig heard Richard Faidley yelling "Dad" and realized that James Faidley was under the fall. David Lubinsky, roof-bolting machine operator/emergency medical technician, arrived, assessed Molesky's injuries and provided first-aid. Other members of the crew arrived at the scene, began to gather roof support material and remove rock to recover James Faidley. Larry Rager, roof-bolting machine operator, phoned outside and notified Don Foster, electrician, of the accident. Lubinsky assisted Molesky to the surface.

MSHA was notified at 5:05 p.m., July 15, 1997, and personnel from the Johnstown and Indiana field offices were sent to the mine. The first MSHA representative arrived at 6:15 p.m. Representatives of the Pennsylvania Department of Environmental Protection (DEP), Bureau of Deep Mine Safety and a Bureau of Deep Mine Safety mine rescue team participated in the recovery. Recovery operations continued until the victim was recovered at 8:30 a.m., July 16, 1997. The victim was pronounced dead at 8:35 a.m., July 16, 1997, by Dr. James Dickson. The cause of death was asphyxiation.

INVESTIGATION OF ACCIDENT



The MSHA accident investigation team was assembled and the investigation into the cause was started on July 17, 1997.

MSHA and the Pennsylvania DEP jointly conducted the investigation with the assistance of mine management and the miners.

PHYSICAL FACTORS

  1. Development at the Sarah Mine started in March of 1997 into the Upper Kittanning seam at the highwall. The mine consists of three drift openings that expand into the seven entry South Mains. The mains were advanced approximately 1,000 feet from the highwall, generally on 70-foot by 70-foot centers, with maximum entry and crosscut width of 20 feet. At the time of the accident five rooms (20 feet wide) were being developed in a westerly direction off the No. 7 entry.

  2. Beginning at the mine openings, the coalbed dips to the southeast at about a 9-degree angle. Total overburden above the mine ranges from less than 40 feet near the western edge of the property to in excess of 800 feet over the southeastern reserves.

  3. The Roof Control Plan, approved July 11,1997, required the use of No. 5, Grade 60 fully grouted bolts, with a minimum length of 48 inches, installed on a 4-foot by 4-foot pattern. When cracks, slips and/or clay veins were encountered in the roof, supplemental support such as steel straps or channels, longer bolts and/or reduced spacing was required. Observations throughout the mine indicated compliance with those provisions of the plan.

    The plan also specified minimum centers of 50 feet for entries and crosscuts, and 40x50-foot centers for rooms. The operator had projected the mains to be mined generally on 70-foot by 70-foot centers. All entry and crosscut centers exceeded the plan minimums.

    The plan permitted a maximum cut depth of 20 feet. However, cuts of only 10 to 15 feet deep were mined at various locations in an attempt to keep 6 to 12 inches of roof from falling.

  4. The main entries (South Mains) were developed approximately 1,000 feet, when the mine encountered an area where the coal height decreased to a point where the equipment could not be operated. At that time, management decided to change the direction of mining. Preparations were made to install a belt drive unit and continue mining left,(east). While the belt drive was being installed, a decision was made to develop rooms to the right (west) in order to keep the mine operating. Prior to mining the rooms, management evaluated the information from existing mine maps and estimated the cover in this area to be 60 to 80 feet. Surveys completed after the accident revealed that the total cover over the accident area was only 38 feet.

  5. Five rooms were mined off the No. 7 entry of the South Mains. The No. 2 room (accident area) was initially developed west approximately 78 feet. A crosscut was turned right toward the No. 3 room and three cuts of coal were mined. Reportedly, the first two cuts (each 15 feet deep) were bolted, but the third cut (10 feet deep) was unsupported. The continuous-mining machine was then moved outby the face of the No. 2 room and mining to the left (south) for the crosscut from the No. 2 room to the No. 1 room was started.

  6. The initial roof fall occurred in the intersection of the No. 2 room and the crosscut being developed. The lower portion of the fall reportedly came in mass, followed by subsequent falls of the upper material. Observations of the fall area indicated that the first 4 to 5 feet of laminated shale (claystone to siltstone) had the appearance of a reasonably well consolidated "beam." The roof bolts reportedly used in this area were 5-foot, fully grouted bolts, installed in conjunction with T-channels.

    The next 8 to 10 feet of massive churned dark gray shale was broken and contained many slickensided surfaces. Above the massive shale was a highly fractured dark gray laminated shale member, 10 to 15 feet thick. Many of the fractures in the dark gray shale were stained, dripping water; orange mud or clay material was noticeable on some of the fracture faces. Two distinct fracture planes were observed in this layer, one oriented in the northeast-southwest direction and the other roughly perpendicular to it. The uppermost portion of the fall sequence appeared to be an orange mud/clay material that "flowed" into the void.

    The left side of the fall appeared nearly vertical for the first 8 to 10 feet and paralleled the angle cut to the left. It then arched through the churned shale to the fractured shale where it rose at a steep angle. The right side of the fall was very steep in its entirety. Total height of the fall was estimated at 25 to 30 feet.

  7. Roof conditions were examined throughout the mine. A distinct joint set (a series of parallel fractures) was observed in the mine roof as clay veins, unfilled fractures or tensile cracks. The most pronounced jointing was oriented in the northeast-southwest direction. A secondary set approximately perpendicular to the main joint set was also observed. In the areas where these joints were observed, supplemental roof support in the form of longer bolts, channels or straps had been installed. Shallow wedge type failures (potted areas) were observed in a number of areas where the two joint sets intersected. The potted areas appeared to have occurred during or shortly after mining as the straps or channels were often tight against the roof within the voids. No evidence of horizontal stress (cutter roof or shifting strata) was observed in the mine. The roof conditions noted (potting out and tensile cracks) appeared to be caused by dead weight sag.

  8. The direction of the mining to the left in the No. 2 room paralleled the direction of the main joint set. However, there were no observable fractures in the area just outby the fall that would have indicated a weakness in the roof at the location where the mining was started.

  9. Five test holes were examined with a borescope in and around the intersection of the No. 7 entry, approximately 40 feet outby the fall. A number of hairline cracks and crushed zones (borehole spalling) were observed. Water was encountered at a depth of 10 to 11 feet into the roof in each hole. However, no open cracks indicative of roof instability were detected. All roof bolters interviewed stated that they did not detect any indication of roof instability during the installation of roof bolts in this area.

  10. No significant pillar deterioration was noted in the mine and sloughing was minimal. The immediate shale floor had generally turned to mud because of the wet conditions, but the underlying limestone remained firm.

  11. A preshift examination for the afternoon shift and an onshift examination for the day shift, July 15, 1997 were conducted. No hazards were recorded in either examination book.

CONCLUSION



The fatal roof fall accident was caused by a combination of factors. The dark gray laminated shale (upper roof) was badly fractured and weathered due to its close proximity to the surface. This deterioration virtually eliminated the bridging capability of the laminated shale roof and resulted in a dead weight loading of the strata below. The churned shale mass directly above the bolted roof contained many slickensides, which reduced its spanning capability. While the immediate roof appeared reasonably well consolidated by the 5-foot long grouted bolts, the presence of joints and fractures may have weakened this strata as well. As the intersection was developed normally and subsequently widened by mining to the left, which removed the coal support, the immediate roof was over-stressed and collapsed with little warning.

ENFORCEMENT ACTIONS

  1. A 103(k) order was issued to ensure the safety of miners until an investigation into the cause of the accident could be conducted.

  2. There were no violations observed that contributed to the accident.




Respectfully submitted:

William D. Sparvieri, Jr.
George J. Karabin
Michael A. Evanto
Thomas H. DeVault



Approved by:

Joseph J. Garcia
District Manager--Coal Mine
Safety and Health District 2


Related Fatal Alert Bulletin:
Fatal Alert Bulletin Icon FAB97C19