DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
COAL MINE SAFETY AND HEALTH
REPORT OF INVESTIGATION
Surface Coal Mine
Fatal Fall of Highwall
May 24, 2000
MTR Surface Mine Number 1
Martin County Coal Corp.
Inez, Martin County, Kentucky
ID No. 15-11005
Accident Investigators
Robert J. Newberry
Mining Engineer
Robert H. Bellamy
Mining Engineer
Originating Office
Mine Safety and Health Administration
District 6
4159 North Mayo Trail
Pikeville, KY 41501
Carl E. Boone, II, District Manager
OVERVIEW
At approximately 5:45 a.m. on Wednesday, May 24, 2000, a collapse of the highwall occurred in the Coalburg highwall miner pit at the Martin County Coal Corp., MTR Surface Mine Number 1. Ronnie Wright, front-end loader operator, was working to move coal from the stockpile at the highwall miner conveyor stacker when the highwall fell onto the Caterpillar 988B front-end loader, resulting in fatal injuries.
The accident occurred due to the highwall mining activity taking place in an area where an unsafe ground condition existed. A hillseam extended nearly vertical and parallel to the highwall face for a distance of approximately 265 feet in length and up to 12 feet in depth. The hillseam, which was exposed to the surface at both ends, was being undermined in the Coalburg seam by the highwall miner. The immediate roof of the mined openings consisted of 10-25 feet of shale overlain by a main roof of sandstone extending up to the Stockton seam near the top of the highwall.
The presence of the hill seam left a large column of rock in a meta-stable condition, with minimal support in the back. In this condition, even minor disturbances would cause it to become unstable. Since the condition was not detected, no modifications to the normal mining procedure were implemented.
The procedure of removing the coal caused stress to the pillars of coal left in place between the mined openings. The overlying shale failed due to deformation of the coal pillars or from failure of the shale overlying the coal. With the failure of the shale, the horizontal support of the sandstone was removed. The parallel hill seam isolated the block of sandstone from the main beam of sandstone. The result was a highwall failure extending for the length and depth of the parallel hill seam.
GENERAL INFORMATION
Martin County Coal Corp., MTR Surface Mine Number 1, is located off Kentucky Route 3, approximately five miles from the town of Inez in Martin County, Kentucky. Martin County Coal Corp. is a wholly owned subsidiary of A. T. Massey Coal Company, Inc., located in Richmond, Virginia. The victim was employed as a contract laborer by Ranger Contracting, Inc., an independent contractor located in Salyersville, Kentucky.
The principal company officers of Martin County Coal Corp. are:
Dennis R. Hatfield ................................... PresidentThe principal company officers of Ranger Contracting, Inc. are:
John R. Stepp ......................................... Surface Mine Manager
Elmer Howard ......................................... Safety Coordinator
Betty Reed ............................................... PresidentMTR Surface Mine Number 1 was placed in active status on December 1, 1980. Coal is produced in four active pits using highwall drills, hydraulic and electric shovels, bulldozers, front-end loaders, rock trucks, and a highwall miner. The company uses several methods of mining, one of which is contour mining with cross-valley fills followed by highwall mining. Area Four (the area where the accident occurred) was conducting this type of mining.
Rondal Reed ............................................ Vice President
The pit where the ADDCAR� Highwall Mining System miner is used operates six days per week, using three crews, seven employees each, who rotate two 12-hour shifts, four days each week. Maintenance is conducted on the seventh day of the week. Martin County Coal Corp. employees contract labor to operate the front-end loader and to provide labor on the ADDCAR� Highwall Mining System. The mine produces an average of 10,000 tons of coal daily. A regular safety and health inspection of the mine was ongoing at the time of the accident.
The ADDCAR� Highwall Mining System uses a Joy 14CM Continuous miner to cut a rectangular opening that is 11.5 feet wide. The height of the opening is determined by seam height. Coal is transported to the surface on a series of conveyor cars that are coupled together. The cars are placed in the launch vehicle with a Caterpillar 988B wheel loader that is equipped with a flat "pan" that slides under the car. The launch vehicle pushes the cars into the opening.
DESCRIPTION OF ACCIDENT
On Tuesday, May 23, 2000, the evening before the accident, the "B" crew arrived at their regular starting time, 6:00 p.m. Darrell Hackworth, foreman, consulted "A" crew foreman James Hensley about the status of the operation. The "A" crew had just finished advancing the No. 1365 opening. The "B" crew began the shift removing the conveyor cars from the No. 1365 opening (see sketch on page 1).
The "B" Crew Members at the time of the accident were:
David Canterbury ...........................................SuperintendentProduction resumed in the No. 1366 opening and proceeded through the night, mining the No. 1366 opening to a depth of 301 feet and the No. 1367 opening to a depth of 301 feet. The next opening, No. 1368, was mined to a depth of 105 feet when the accident occurred.
Darrell Keith Hackworth ................................. Foreman
Fred D.Pierson .............................................. Pan Loader
Jeffrey Dale Hopson ...................................... Pad Technician
Johnny Ray Jude ........................................... Miner Operator
Mose E. Newsome ........................................ Electrician
Thomas P. Yates ........................................... Pad Technician
Ronnie J. Wright..............................................Front-end loader operator (victim)
Other than a fifteen-minute delay at 4:30 a.m. to remove rock from the continuous miner and the No. 1 car, normal operations proceeded throughout the shift. Fred Pierson, pan loader operator, stated that at 5:45 a.m. the victim was moving coal from beneath the stack conveyor and that he (Pierson) was facing that direction waiting to place a car in the launch vehicle when he saw the highwall begin to move. Pierson keyed both the CB and two-way radio microphones and shouted a warning that the highwall was falling. Pierson further stated that he saw the victim's front-end loader begin to move in high gear away from the wall in an apparent attempt to escape the fall area. The massive slab of rock toppled from the highwall and crushed the front-end loader with the victim inside. Pierson was the only witness who actually saw the rock fall.
Hopson and Jude were in the control booth of the launch vehicle when they heard Pierson's warning. They attempted to exit the booth, but returned to escape the falling debris. Yates was on the launch pad when the rock began to fall and he heard Pierson's warning on his hand-held two-way radio. Yates ran in the opposite direction from the fall. Newsome stated that he had his back to the area where the rock began falling and after he heard the rock fall he turned to see a cloud of dust created by the falling rock. The front-end loader was completely buried under the broken rock. Attempts to reach the victim were unsuccessful due to the size of the boulders covering the front-end loader. The Kentucky Department of Mines and Minerals Rescue and Recovery Unit was summoned to direct recovery of the victim. A Caterpillar D11 bulldozer, two hydraulic excavators, and a Caterpillar 992C wheel loader were mobilized to move the fallen rock from the buried wheel loader. Access to the victim was provided and he was pronounced dead at 10:40 a.m. by the Martin County Coroner. The recovery efforts continued until 12:10 p.m. when the victim was transported to the Office of the State Medical Examiner.
INVESTIGATION OF THE ACCIDENT
At 6:30 a.m. on May 24, 2000, Elmer Howard, Safety Coordinator for MTR Surface Mine Number 1, called the MSHA Martin Field Office and reported the accident to Wanda Hinkle, Surface Coal Mine Inspector. At the time of the initial notification the condition of the victim was unknown. Hinkle proceeded to the accident scene and issued 103(k) orders to Martin County Coal Corp. and Ranger Contracting, Inc. Although the affected area was the entire highwall mining pit, the order was modified to allow the use of heavy equipment to assist in the recovery effort.
Danny Harmon, Roof Control Supervisor, and Larry Little, Roof Control Specialist, went to the scene to assist in the recovery effort. Mining Engineers/Accident Investigators Robert Newberry and Robert Bellamy were dispatched to the scene and arrived at approximately 9:00 a.m. Representatives from the Kentucky Department of Mines and Minerals (KDMM), Martin County Coal Corp., and Ranger Contracting, Inc. were present at the accident scene. Recovery work continued until 12:10 p.m. when the victim was extricated and transported to the Medical Examiner's Office.
The accident area was photographed, sketched, videotaped, and measured to the extent possible. The physical investigation of the accident was hindered by the size and location of the large boulders in the debris area. The investigation team returned to the scene on May 25, 2000, in order to take additional photographs and the fall area was surveyed by Martin County Coal Corp. on May 25, 2000. George Gardner and Darren Blank, civil engineers from MSHA Technical Support, examined, photographed and measured the area with a laser distance measuring device. Paul Tyrna, Geologist, and Bill Williams, Mining Engineer, from MSHA Technical Support arrived on June 1, 2000, to evaluate the overall ground conditions and identify geologic conditions that contributed to the highwall instability.
Interviews were conducted on May 25, 2000, at the Martin County Coal Corp. Training Center. Eight persons deemed to have relevant information concerning the accident were interviewed jointly by MSHA and KDMM. Additional interviews of six persons were conducted on May 31, 2000.
DISCUSSION
1. The accident occurred at Martin County Coal Corporation, MTR Surface #1 Mine, Area 4, on the Coalburg Coal Seam contour bench.
2. Ronnie Wright, victim, had 23 years mining experience, 4 years, ten months of which were obtained at this mine as a front-end loader operator. His annual refresher and task training was up-to-date.
3. Operations in the area were to consist of highwall mining along approximately 1200 feet of a highwall which was created by contour strip mining. The highwall had been pre-split (hole spacing approximately 5 feet) during the contour mining operations, which took place several weeks prior to the accident.
4. The highwall ranged from 65 to 95 feet high in the accident location. The angle of the highwall was approximately 90 degrees and contained no benches.
5. The highwall in the accident location consisted of two to 15 feet of soil and highly weathered rock at the surface. Below this material was the Stockton coal seam which was approximately five to six feet thick. The Stockton seam had not yet been mined in this location. A 35 to 50 foot thick massive sandstone layer existed beneath the Stockton seam. This sandstone was underlain by a 10 to 25 foot thick layer of laminated gray shale. The Coalburg coal seam was beneath the shale at the bench level. The Coalburg seam was approximately four to five feet thick. The miner operator reported that a soft shale existed at the bottom of the Coalburg coal seam.
6. The bench was approximately 100-150 feet wide in the accident location, and it was bounded by the highwall on one side and a safety berm on the other. The bench was typically about 125-150 feet wide elsewhere in this section.
7. Highwall mining operations began in this area on May 22, 2000. Mining was initiated at the "point" in the SE corner of the area and was progressing in a general southeast-to-northwest direction.
8. The company was performing highwall mining operations using the ADDCAR� Highwall Mining System. The system utilizes a continuous miner and belt cars operated remotely from a launch vehicle with overhead falling object protection. Coal is cut by a continuous miner, conveyed along conveyor cars (addcars) using a cascading conveyor belt system to the launch vehicle. From there the coal is conveyed using a stack conveyor to a temporary stockpile. The addcars are approximately 41 feet long and 10 feet wide.
9. The highwall miner cuts entries approximately 11.5 feet wide. Approximately eight-foot-wide web pillars were being left between the entries. According to the ground control plan, the web pillars were required to be a minimum of four feet wide. Company personnel reported that the minimum requirements for web pillars were exceeded to provide additional support in areas where they intended to mine the Stockton seam in the future.
10. The miners reported that the highwall miner had not cut into previously-mined entries.
11. At the time of the highwall failure, the stack conveyor was positioned on the side of the launch vehicle where the Coalburg seam had already been mined (to the southeast of the launch vehicle.) It is normal practice at this mine to place the coal stockpile on the previously-mined side of the launch vehicle.
12. A Caterpillar 988-B front-end loader was used to load the coal haulage trucks from the stockpile. The last truck had been loaded at approximately 4:00 a.m. Additional haul trucks were scheduled to arrive at 6:00 a.m. At the time of the accident, the front-end loader was moving stockpiled coal away from the stack conveyor to a location from which it would later be loaded onto haulage trucks.
13. Eleven entries had been advanced in the Coalburg seam between May 22, 2000 and May 24, 2000, designated sequentially as 1357 through 1367, inclusive. The company was in the process of mining the twelfth entry (1368) when the highwall failure occurred.
14. Entry locations are routinely laid out and marked on the highwall by the company's engineering department prior to mining.
15. The three entries driven prior to the failure were advanced to a depth of approximately 300 feet. They had been projected to more than 600 feet, but the miner operator reported that the coal was pinching out.
16. No barrier pillars had been left in the area being mined (i.e., web pillars were uniformly and regularly spaced; no entries had been skipped) The ground control plan indicated that, "When necessary, barrier pillars will be provided after every fifth hole or more often if necessary depending upon conditions." Barrier pillars have been created by skipping an entry and would be approximately 11.5 feet wide.
17. The shift foremen made the decision as to when and where barrier pillars were left. Conditions that normally dictated leaving barrier pillars included coal flaking or popping off of the web pillars or the top coming down. Since these conditions had not existed, the foreman had not considered a barrier pillar to be necessary at the accident location.
18. Previously driven entries were routinely blocked or buried at the highwall, making it impossible to observe the condition of the web pillars in previous holes. The ground control plan indicated that, "Auger holes will be blocked during the course of the normal mining cycle."
19. The highwall failure occurred at 5:45 a.m. Sunrise was at 6:09 a.m on this date. It was reported that the area was well-lighted with eight 1500-watt floodlights mounted on the launch vehicle. There was also a portable light plant with four additional 1500-watt bulbs illuminating the highwall. The miners considered illumination to be adequate.
20. The temperature ranged from 59-85 degrees Fahrenheit for the 24 hours before the failure. There was some rainfall in the area during the morning of May 23, 2000, however conditions were reported to be dry at the time of the highwall failure.
21. During the investigation, there was no significant flow of water noted at any location along the highwall.
22. The highwall orientation was estimated to be as follows in the area where the failure occurred:
Location Highwall Bearing Entries1357 - 1359 N 55 W23. Entries designated 1358 through 1368 were bearing at approximately S67 30' W, at an angle to the highwall.
Entries 1360 - 1364 N 37 W
Entries 1365 - 1372 (projected) N 50 W
24. A number of joints were evident from an inspection of the highwall, and there were two distinct joint strike orientations. The predominant joint set had a typical strike of N60 W and ranged from N35 W to N70 W. The subordinate joint set had an average strike of N20 E. The joints were steeply dipping to near vertical. The strike of the predominant joint set was nearly parallel to the highwall face in the accident area.
25. Mine personnel indicated that, when encountering what they believed to be an unsafe area of highwall, the shift foremen made the decision whether or not to mine the coal in that area. Conditions such as loose rock hanging on the highwall can lead to this decision. In other areas of this mine, when unsafe highwall conditions had been encountered, coal was left in place. Depending upon the severity of the condition, the launch vehicle can also be moved further back away from the wall to minimize exposure. They have reportedly moved as far as eighty feet back from the highwall when there have been concerns with conditions of the highwall.
26. The foreman had examined the highwall upon beginning his shift at approximately 5:50-6:00 p.m. on May 23, 2000. He, as well as the other miners, also routinely observed the wall throughout their shift.
27. Based upon his examination, the foreman recorded the condition of the highwall as "fair".
28. At no time during the shift was the ground surface above the highwall examined. A road existed to the top of the highwall which would have facilitated an inspection in this area.
29. Considerable amounts of draw rock needed to be cleaned off of the ADDCARs' just behind the miner head in the two entries advanced prior to the failure. The draw rock consisted of immediate roof material, and was approximately 6 to 12 inches thick.
30. It was common for some of the shale roof material to fall into the opening when the entry was initially excavated.
31. The highwall failed along a large joint or "hill seam" which was nearly vertical and parallel to the face of the highwall. This joint ran along the back of the failure mass over its entire length. The orientation of this joint was consistent with that of the predominate joint set. The joint was found to be highly stained and contained gouge, indicating that it was a geologic feature which likely existed prior to mining.
32. The highwall failed over a length of approximately 265 feet. The failure ranged from about 5 to 12 feet thick. The highwall varied in height from about 65 to 95 feet.
33. The highwall failure was confined predominantly to that section of the wall which had been mined using the highwall mining system.
34. The highwall failure was massive, involving an estimated 7,500 cubic yards of rock.
35. Debris from the highwall failure covered approximately 3/4 of the bench width in the accident location.
36. The failure mass was comprised of many large intact blocks of rock, some as large as 20' by 20' by 10'.
37. There had been other incidences of highwall failure at the mine which were reportedly investigated by the company.
38. At the time of the highwall failure, the victim was operating a CAT 988B front-end loader and was approximately 55 to 60 feet away from the highwall. The loader was traveling in a southeasterly direction, away from the highwall and toward the berm. The Caterpillar 988B front-end loader was completely buried by rock debris.
39. The launch vehicle was estimated to be within about 35 feet of the highwall at the time of failure. It sustained significant structural damage when the front left corner was struck by falling debris. The launch vehicle was approximately 16 feet wide and 60 feet long.
40. There was one eyewitness who observed the highwall as it failed. He was operating a CAT 988B loader with a lift ("pizza pan") assembly on the northwest side of the launch vehicle.
41. The eyewitness reported that he saw dust coming off of the wall just before the failure. He radioed to the other personnel using both the two-way radio and citizens band radio. Within a matter of seconds, the entire wall had collapsed. None of the witnesses reported any movement of the wall prior to this time.
42. According to this witness, the highwall first moved downward and then toppled (rotated top-first) out onto the bench.
CONCLUSION
The accident was a direct result of the mine operator's failure to detect, recognize, and/or take appropriate measures regarding an adverse geologic condition in the highwall in an active highwall mining area. The adverse condition consisted of a continuous nearly-vertical joint, or hill seam, running nearly parallel to the highwall. The presence of this joint left a large, relatively narrow column of rock in a marginally stable condition, with minimal support in the back. In this condition, even minor disturbances would cause it to become unstable. Since the condition was not detected, no modifications to the normal mining procedure were implemented.
The mechanism which actually triggered the failure is considered only a secondary cause of the accident, and is likely one, or a combination of the following:
Slippage along a joint, or a degraded or weak plane in the shale or coal layer beneath the massive sandstone.
Vibration caused by operation of the highwall mining system.
Undermining of the massive sandstone due to degradation of the shale or coal creating a slight overhang or brow.
Crushing or deformation of the coal pillars.
Deformation or bearing capacity failure of the soft shale floor beneath the web pillars.
ENFORCEMENT ACTIONS
1. A 103(k) order No. 7364706, was issued to Martin County Coal Corp. under the provisions of Section 103(k) of the Mine Act to assure the safety of miners until the investigation could be conducted.
2. A 103(k) order No. 7364707, was issued to Ranger Contracting, Inc., under the provisions of 103(k) of the Mine Act to assure the safety of miners until an investigation could be conducted.
3. A 104(a), citation No. 7373408, was issued to Martin County Coal Corp., under 30 CFR 77.1000, because the acknowleged ground control plan was not being followed. Barrier pillars were not provided every five holes where highwall mining was being conducted.
4. A 104(a), citation No. 7369116, was issued to Martin County Coal Corp., under 30 CFR 77.1004(b), because an unsafe ground condition in the form of a hill seam running parallel to the highwall face in the Coalburg seam highwall miner pit was not corrected or the area posted.
5. A 104(a), citation No. 7369117, was issued to Martin County Coal Corp., under 30 CFR 77.1713(a), because the examinations for hazardous conditions in the Coalburg seam highwall miner pit were not adequate. The hazards associated with the presence of a hillseam were not addressed. The examinations conducted from the time which the highwall miner began operations in this pit, May 22, 2000, until the date of the accident, did not identify any hazardous conditions.
Related Fatal Alert Bulletin and Accident & Injury Report(s):
FAB00C14 A & I Reports
- (File is PDF)
Map of Workers at time of accident.
Photo showing location of ADDCAR�
APPENDIX
List of Persons Participating in the Investigation
Martin County Coal Corp. Officials
List of Persons Participating in the Investigation
Elmer Howard Safety CoordinatorUniversal Coal Services, Inc.
Shane Harvey ............... Attorney
Mark Heath ............... Attorney(Heenan, Althen and Roles)
David Canterbury ............... Superintendent
Saul Akers Safety Director (representing Universal Coal Services employees)Ranger Contracting, Inc.
Steve Vanhoose ............... ForemanKentucky Department of Mines and Minerals
Dion Reed ............... Foreman
Tracy Stumbo ............... Chief InvestigatorMine Safety and Health Administration
Bobby Sexton ............... Safety Inspector
Jerome Howard ............... Safety Analyst
Keith E. Conley ............... Safety Analyst
Robert Newberry ............... Mining Engineer
Robert Bellamy ............... Mining Engineer
Danny Harmon ............... Supv. Coal Mine Specialist
Larry Little ............... Coal Mine Specialist
Wanda Hinkle ............... Surface Coal Mine Inspector
Thomas A. Grooms ............... Attorney
John Shutack ............... Mining Engineer
John South ............... Accident Investigation Coordinator
Gerald W. McMasters ............... Conference Litigation Representative
George Gardner ............... Civil Engineer
Darren Blank ............... Civil Engineer
Paul Tyrna ............... Geologist
Bill Williams ............... Mining Engineer
Harold Thornsbury ............... Training Specialist
APPENDIX B
List of Persons Interviewed
List of Persons Interviewed
Thomas P. Yates ............... Pad Technician (Universal Coal Services)
Darrell Keith Hackworth ............... Foreman
Fred Pierson ............... Pan Loader Operator
David E. Canterbury ............... Superintendent
Jeffrey Dale Hopson ............... Pad Technician
Johnny Ray Jude ............... Highwall Miner Operator
Mose E. Newson ............... Electrician
Dion Reed ............... Foreman (Ranger Contracting, Inc.)
Brian Castle ............... Pad Technician(Universal Coal Services)
David Duane Conn ............... Pan Loader Operator
Bobby Moore ............... Highwall Miner Operator
Roger Dean Hunt ............... Pad Technician
James William Ward ............... Front-End Loader Operator