DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
COAL MINE SAFETY AND HEALTH
REPORT OF INVESTIGATION
Underground Coal Mine
Fatal Fall of Roof Accident
August 31, 2001
Sebastian County Coal Mine
Mid-America Mining & Development, Inc.
Hartford, Sebastian County, Arkansas
ID No. 03-01736
Accident Investigators
William E. Vetter
Coal Mine Safety and Health Specialist (Health)
John R. Cook
Mining Engineer
Sandin E. Phillipson
Geologist
David L. Weaver
Mine Safety and Health Specialist (Training)
Originating Office
Mine Safety and Health Administration
District 9
P.O. Box 25367
Denver, Colorado 80225-0367
Allyn C. Davis, District Manager
Report Release Date: 12/04/2001
OVERVIEW
On Friday, August 31, 2001, at approximately 9:15 a.m., a roof fall occurred in a newly opened, unsupported side cut in Crosscut 6 off the No. 3 Entry at the Sebastian County Coal Mine. The roof fall caused fatal injuries to a 38-year old miner helper, who had approximately five weeks total mining experience. Mining in the side cut had been halted due to the continuous mining machine becoming stuck on loose material and adverse floor conditions. Cleanup of the floor in the No. 3 Entry inby the crosscut was in progress at the time of the accident.
As loose material was being loaded inby the unsupported side cut, a roof bolting machine operator and the miner helper positioned themselves in the side cut area. Without warning, a section of roof fell striking the two miners. The miner helper was fatally injured and the roof bolting machine operator received minor injuries.
When coal was mined from the initial side cut in Crosscut 6, the fragile sandstone roof was unable to support itself. Large sections of the unsupported roof fell during mining, without incident. The newly exposed roof in the side cut was left unsupported while cleanup procedures took place inby the side cut, a violation of the approved Roof Control Plan.
Roof bolts, previously installed in the No. 3 Entry along the right rib where the side cut was started, were oriented in such a way that the line of roof bolts arced toward the center of the entry. This reduced the width of the supported roof within the entry and lengthened the distance from the nearest support to the deepest point of penetration in the side cut. Due to this narrowing of roof supports, the victim and a roof bolting machine operator inadvertently positioned themselves under unsupported roof in the newly exposed area of the side cut, a violation of 30 CFR 75.202(b). The two miners most likely were avoiding the shuttle car as it was being loaded in the No. 3 Entry. Fatal injuries resulted when roof material from the unsupported side cut fell directly on the victim.
The causes of the accident were: 1) the failure to support the newly exposed side cut area before cleaning the floor in the No. 3 Entry inby the unsupported side cut; and 2) the victim inadvertently positioning himself under unsupported roof inby the rib bolts in the side cut area. The location of the arced rib line roof bolts, which narrowed the supported area in the No. 3 Entry, contributed to the accident. The victim's limited mining experience (approximately five weeks total) may have contributed to his inadvertently placing himself in a hazardous location.
GENERAL INFORMATION
The Sebastian County Coal Mine is an underground mine located along South Pine Street, one mile east of Hartford, Sebastian County, Arkansas. It is owned and operated by Mid-America Mining & Development, Inc. (Mid-America). Mid-America is a subsidiary of Ohio Holdings, Inc., located in Maumee, Ohio. Beginning in June 1992, the property was developed and mined as a surface operation, the Wilkem #1 Mine (ID No. 03-01726). By April 1993, the mine had produced 30,000 tons of coal from the Lower Hartshorne coal seam. It was used primarily as power plant steam coal and kiln fuels for cement plants. In June 1993, three portals for the Sebastian County Coal Mine, which initially was also known as the Wilkem #1 Mine, were developed from the highwall of the Wilkem #1 surface pit. The Lower Hartshorne seam dips approximately 7� to the southwest. It consists of a 42- to 48-inch thick coal seam, which is underlain by a 8- to 12-inch gray shale parting (rash), which in turn is underlain by a 6- to 15-inch thick coal split.
By June 1994, a contract mining company had developed three entries from the portal openings for a maximum distance of approximately 580 feet. In addition, a "turn around," which eventually became the No. 4 Entry, was developed to the right of No. 3 entry at Crosscut 3. It extended one break inby Crosscut 3 and reconnected to the No. 3 Entry. The intended purpose of the "turn around" was to store rock. At that point, mining ceased and the mine was placed in a non-producing status. One employee was retained to pump water and to maintain the mine's ventilation system.
In June 1995, Mid-America became the official operator of the mine and continued to maintain it in a non-producing status until May 2001. During the time the mine was in non-producing status, it flooded as a result of surface storms and groundwater seepage. Cleanup and rehabilitation work began after a Roof Control Rehabilitation Plan was approved by MSHA on May 29, 2001. A Ventilation Plan was subsequently submitted and approved on July 20, 2001. Following the rehabilitation of the previously developed workings, a Roof Control Plan was approved on August 1, 2001, and the No. 1 Entry was driven approximately 100 feet beyond the extent of the previously mined face. The Nos. 2 and 3 Entries were driven approximately 75 feet beyond the previously mined faces and an additional entry, No. 4, was connected to the "turn around" and driven approximately 230 feet inby. The face of the No. 3 Entry, which represents the maximum extent of the main entries, had been advanced to approximately 650 feet from the highwall at the time of the accident.
The mine was ventilated with a Jeffrey, 40 horse power, fixed blade main fan. On a blowing system, the main fan, which produced 51,000 cubic feet of air per minute, induced air into the mine at the No. 3 Entry portal. According to samples collected by MSHA, the mine was not liberating any detectable methane gas. One active working section, South Mains (MMU-001), was being developed by utilizing an umbilical cord remote-controlled Joy 14CM10AAX mining machine, a Phillips Machine PM 21-10 shuttle car (a rebuilt Joy 10SC32 shuttle car), and a Fletcher Model DDO-15-E.C-D, twin boom roof bolting machine. Conveyor belt haulage was used from the working section to the surface.
A total of 16 persons were employed at the mine, 11 underground and 5 on the surface. Mine operations were scheduled for two shifts per day, Monday through Friday, with one production shift of 11 employees and one maintenance shift with 5 employees. Each shift was scheduled for nine hours. Dealing with the effects of the mine having been flooded and equipment failures, production of coal was very inconsistent and an average daily production tonnage was not of any significance.
The Non-Fatal Days Lost (NFDL) incidence rate for the mine for January through June, 2001, was 0.00, while the industry average was 7.00. The last complete regular inspection (AAA) by MSHA concluded on June 26, 2001. A regular inspection (AAA) had begun on July 10, 2001 and was ongoing at the time of the accident.
The principal officers of the mine at the time of the accident were:
Raymond F. Parker ........ Mine Manager/SuperintendentThe highest levels of supervision at the mine when the accident occurred were:
William McNabb ........ General Mine Foreman
Raymond F. Parker ........ Mine Manager/Superintendent
Darrel W. Cash ........ Temporary Section Foreman/Continuous Mining Machine Operator
DESCRIPTION OF THE ACCIDENT
Darrel Cash, continuous mining machine operator/temporary section foreman, completed the preshift examination for the day shift at approximately 7:00 a.m., Friday, August 31, 2001. Cash routinely conducted this preshift examination. While on the working section, Cash called William (Pete) McNabb, General Mine Foreman, and reported that no significant hazards were found during his preshift examination. McNabb recorded the results and told Cash where to begin mining. McNabb also told Cash that he would be responsible for the section as the certified person. McNabb had made arrangements to be off mine property at the beginning of the shift, but was planning to return during the shift to resume his duties as the certified person on the working section.
After Cash made his preshift report, the remaining five crew members entered the mine. They traveled through the air lock doors in the No. 3 Entry and walked approximately 600 feet to the South Mains working section (MMU-001). According to interviews, Cash's instructions to the crew were brief but included mining a side cut from No. 3 Entry to develop Crosscut 6 toward No. 4 Entry. The crosscut was to be mined toward No. 4 Entry by turning off the straight of No. 3 Entry rather than from the crosscut connecting the Nos. 2 and 3 Entries. This was due to an impassable floor condition in the No. 2 Entry.
Mining of the side cut began soon after the crew arrived on the section. In typical fashion, the top coal split, approximately 42 to 48 inches thick, was mined first during the initial cuts of the mining cycle. The underlying parting (rash) and bottom coal, which together were from 14 to 27 inches thick, were to be mined later after the cut was fully developed. Leaving the parting and bottom coal caused the floor to be on an inclined plane. The combination of the dipping coal seam and the abrupt incline caused the continuous mining machine to become stuck while developing the side cut. It was necessary to free the machine several times by pulling on it with the shuttle car, using a chain.
During this mining cycle, a portion of the unsupported immediate roof fell. It broke at the perpendicular jointing in the rock strata and fell in considerably large pieces. One piece fell and remained on the right fender of the continuous mining machine. The extent of fallen roof in the triangular shaped side cut was approximately five or six feet from the previously installed roof bolts nearest the original right rib of the No. 3 Entry.
Loose floor material, churned up by the spinning tracks of the continuous mining machine and coal cuttings from the cutter head, contributed to the mining machine becoming stuck. Cash made the decision to clean the loose material from the intersection, with the intent of preventing any further problems. In doing so, he planned to load the material into the standard-side shuttle car. According to interviews, the continuous mining machine, operated by Cash using an umbilical cord remote-controlled unit, was first maneuvered down dip on the right side of the No. 3 Entry past the newly developed side cut opening.
A second pass was made on the left side of the entry. During this pass, Cash was positioned on the right side of the entry between the continuous mining machine's bumper and the opening to the unsupported side cut area. The shuttle car, operated by Levi Blair, was under the tail boom of the mining machine as coal was loaded into it. James Roberson, roof bolting machine operator, and Justin Morgan, miner helper (victim), were positioned in the newly developed side cut opening while tending the trailing cable for the continuous mining machine. Roberson was standing approximately five to ten feet from Cash and Morgan was standing next to and outby Roberson. Morgan and Roberson were near the mid-point of the shuttle car as it was in the intersection being loaded.
At approximately 9:15 a.m., without warning, a section of mine roof fell from the unsupported side cut area where Morgan and Roberson were standing. Hearing the fall, Cash turned to see Roberson, who was trying to get up, but he couldn't see Morgan. Roberson was struck by a combination of rocks, knocking him to the mine floor. He was held down by rock resting on his left shoulder and left leg. After Cash assisted Roberson in removing the rock, they began looking for Morgan. He was found covered by rock from the roof fall.
Immediately after the roof fall, the shuttle car was removed from the scene, and Cash sent Blair to the surface to notify Raymond Parker, Mine Manager/Superintendent. Garrick Williamson, diesel scoop operator, was sent outby to retrieve a diesel powered Wagner scoop to aid in the rescue attempt. Jon Bair, roof bolting machine operator, arrived at the accident scene from another location on the section. Cash, Roberson, and Bair were using slate bars to remove Morgan from under the rock when the diesel scoop arrived. Morgan's foot remained pinned under the rock and the diesel scoop was used to lift and push the rock enough to finally free Morgan. At some point, while removing Morgan from under the rock, his vital signs were checked, and it was determined that he had not survived the accident. As Morgan was being removed from under the rock, Parker arrived at the scene carrying a small hydraulic lifting jack and first aid equipment. Parker made another check of Morgan's vital signs to confirm the previous findings.
Morgan was placed on a stretcher and carried to the surface where he was pronounced dead by the Sebastian County coroner. Roberson was transported by ambulance to St. Edward Mercy Hospital in Ft. Smith, Arkansas. He was treated for shock, bruises and abrasions to the left shoulder and leg, and released.
INVESTIGATION OF THE ACCIDENT
The MSHA McAlester, Oklahoma field office was notified of the accident at approximately 10:00 a.m., August 31, 2001. Field office personnel traveled to the mine to conduct a preliminary investigation and examine the accident site. The area had been secured and recovery operations completed under the direction of mine management. Preliminary information was obtained and a Section 103(k) order was issued to assure the safety of the miners.
An MSHA investigation team was formed, with William E. Vetter, Coal Mine Safety and Health Specialist (Health) from Delta, Colorado, assigned as the Lead Investigator. Other members included Technical Support personnel, John R. Cook, Mining Engineer, and Sandin E. Phillipson, Geologist, both from Triadelphia, West Virginia. David L. Weaver, Training Specialist with Educational Field Services from Rolla, Missouri, also assisted.
The investigation team arrived at the mine and began the investigation on September 1, 2001. Accompanying the team were mine management personnel. Reviewing records and traveling to the accident site to measure and sketch the scene, the investigation team identified mine personnel for interviews. Photographs were taken of the accident site and the working section with a digital camera. Witness interviews were conducted on September 2, 2001, at the mine office. Appendix B contains a list of persons interviewed during the investigation. A list of persons participating in the investigation is contained in Appendix A.
DISCUSSION
1. The Wilkem #1 Mine, an abandoned surface mine, provided access to the Lower Hartshorne coal seam for the development of the Sebastian County Coal Mine portals. From June 1992 to April 1993, 30,000 tons of coal were mined from the Wilkem #1 Mine surface pit. The portals for the Sebastian County Coal Mine were developed in June 1993 into the highwall of the Wilkem #1 Mine.
2. The Sebastian County Coal Mine was accessed by three drift portals, numbered 1 to 3 from left to right. These entries were developed by a previous operator to a maximum extent of approximately 580 feet before mining was discontinued in June 1994. A "turn around," which became No. 4 Entry, was also developed to the right of No. 3 Entry at Crosscut 3, a distance of approximately 325 feet from the portal. It was intended to be used as an area to store rock.
3. Reportedly, after mining operations ceased in 1994, the previous operator pumped water from the mine and continued to maintain the mine ventilation system. Water, draining from the strata above the coal seam and entering the portals from precipitation on the surface, accumulated at the faces. At times, the amount of water accumulations flooded the mine. In June 1995, Mid-America became the official operator and continued to maintain the mine in a non-producing status.
4. The Lower Hartshorne seam dips approximately 7� to the southwest. Typically, the coal seam is 42 to 48 inches thick. It is underlain by an 8- to 12-inch thick parting of gray shale (rash), which in turn is underlain by a 6- to 15-inch thick coal split.
5. Abandoned underground mines, that reportedly operated from 1924 to 1948, were located on each side of the Sebastian County Coal Mine.
6. In the No. 3 Entry, between Crosscuts 5 and 6, the upper coal split was up to 51 inches thick and underlain by 8 to 10 inches of brown fissile shale. Although the typical total mining height was approximately 6 feet, measured heights ranged from 4 feet 6 inches to 8 feet 6 inches in the last block developed in the No. 3 Entry.
7. Rehabilitation of the underground workings by the current operator, Mid-America, began in May 2001. Active mining began approximately four weeks prior to the fatal accident. During the four weeks of active mining, the No. 1 Entry was driven approximately 100 feet beyond the extent of the previously abandoned face. Nos. 2 and 3 Entries were driven approximately 75 feet beyond the previously abandoned faces, and No. 4 Entry was connected to and driven approximately 230 feet beyond the "turn around". The face of the No. 3 Entry, which represents the maximum extent of the main entries, had been advanced to approximately 650 feet from the highwall at the time of the accident.
8. The mine had one development section utilizing a Joy 14CM10AAX remote controlled continuous mining machine. At the time of the accident, the continuous miner was being operated with an umbilical cord remote control. The umbilical cord measured 28 feet 6 inches from the end of the boom. The overall length of the continuous mining machine was measured as 33 feet 2 inches. Prior to the investigation, the mining machine had been moved from its position at the time of the accident, and was parked in the No. 3 Entry, one crosscut outby the accident site. A Phillips Machine, Model PM 21-10, standard side shuttle car (a rebuilt Joy 10SC32 shuttle car) was used for section haulage. Conveyor belt haulage was used to transport coal from the working section to the surface.
9. Primary roof support consisted of grade 60, �-inch diameter, 4-foot long fully grouted bolts with 6-inch by 6-inch doughnut-embossed plates. Bolt spacing was nominally on 4-foot centers, although spacing as close as 2.5 feet was observed. Five- and 6-foot long non-tensioned grouted roof bolts were also observed on the bolting machine. The operator stated that the longer bolts were used where deemed necessary.
10. Roof bolts, along the right rib in the No. 3 entry at the newly exposed side cut opening, were installed in such a manner that their alignment took on an arcing pattern. The pattern arced toward the center of the entry. This narrowed the normal width of the supported area within the entry and lengthened the distance from the end of the side cut to the nearest roof support.
11. Floor elevation and surface topography contours indicated that overburden was approximately 80 feet thick at the accident site. Overburden at the portals was approximately 55 feet. Topography remained relatively flat in the direction of main entry orientation as mining was projected to proceed. Mining was proceeding down dip at approximately 7� as measured on floor elevations in the No. 3 Entry. A corehole indicated that 172 feet of overburden occurred 1,325 feet from the highwall in the direction of current mining.
12. Moisture stained fractures and intermittent dripping were observed throughout the No. 3 Entry roof. Water inflow, characterized by steady dripping and small streams, was observed from fractured roof in the extent of previously mined workings. Faces of all entries were flooded with at least 2 feet of water. Fractures in recently mined areas showed coatings of orange iron hydroxides.
13. Up to 14 inches of thinly bedded shale were observed throughout the No. 3 Entry roof, although shale thickness was as little as 2 inches at the accident site. The shale was overlain by sandstone along an irregular contact. Throughout the entry, shale had commonly fallen out to bedding-parallel polished slickenside surfaces. Shale in the roof was very slabby, commonly occurring in 3-inch thick beds, and breaking along the perpendicular joints into blocks. Joints in the shale were stained by recent water seepage and orange iron hydroxide staining was prevalent along horizontal slickensides. Vertical fractures had developed in the shale along bolt holes.
14. The fatal roof fall occurred in the newly exposed area of a side cut at Crosscut 6. Crosscut 6 was being developed from a three-way intersection as a right-hand turn toward No. 4 Entry. At the time of the accident, the crosscut had been developed to a depth of 15 feet inby the rib line roof bolts and consisted of a pie shaped cut that had not been supported.
15. The approved Roof Control Plan (Item 7, Page 4) requires the following support for newly created side cuts:
"When new openings are created and/or side cuts are made, the newly exposed area shall be supported with permanent roof supports according to the plan, before any other work is permitted in or inby the intersection."16. The rock that struck and killed the victim fell from the unsupported roof of the side cut in Crosscut 6. The rock was a wedge-shaped block of sandstone that measured approximately 6 feet long, from 3 to 21 inches thick, and from 34 to 60 inches wide. The estimated weight of the fallen sandstone block was approximately 3000 pounds.
17. The roof fall material was a well-cemented sandstone, but very blocky because of joint orientations. These joints strike N 80� E and N 10� W to form perpendicular intersections, resulting in a crosshatched pattern that defined blocks ranging in size from 10 inches to 3 feet long. Randomly oriented open fractures, with an aperture up to � inch, occurred within sandstone in the roof of the accident site.
18. A sandstone lens was exposed in the roof of the incomplete crosscut at the accident site. The sandstone lens was approximately 1 inch thick in the roof of the No. 3 Entry and thickened into the crosscut, defining a wedge shape. The sandstone wedge exposed in the accident site fall cavity (No. 3 Entry/ Crosscut 6) was bounded by polished slickensides, one parallel to the coal seam roof and the other gradually inclined up into the roof.
19. Sebastian County Coal Mine's training plan was approved by MSHA on January 10, 1994. Training records for the victim and co-workers were examined and indicated that all appropriate training was provided in accordance with Part 48, Title 30 of the Code of Federal Regulations.
20. The victim was a new miner with approximately five weeks of mining experience.
CONCLUSION
When coal was mined from the initial side cut in Crosscut 6, the fragile sandstone roof was unable to support itself. Large sections of the unsupported roof fell during mining, without incident. Loose material prevented mining from continuing in the crosscut and was being cleaned up in the No. 3 Entry by the continuous mining machine. The newly exposed roof in the side cut was left unsupported while cleanup procedures took place inby the side cut, a violation of the approved Roof Control Plan.
Roof bolts, previously installed in the No. 3 Entry along the right rib where the side cut was started, were oriented in such a way that the line of roof bolts arced toward the center of the entry. This reduced the width of the supported roof within the entry and lengthened the distance from the nearest support to the deepest point of penetration in the side cut. Due to this narrowing of roof supports, the victim and a roof bolting machine operator inadvertently positioned themselves under unsupported roof in the newly exposed area of the side cut, a violation of 30 CFR 75.202(b). The two miners most likely were avoiding the shuttle car as it was being loaded in the No. 3 Entry. Fatal injuries resulted when roof material from the unsupported side cut fell directly on the victim.
The causes of the accident were: 1) the failure to support the newly exposed side cut area before cleaning the floor in the No. 3 Entry inby the unsupported side cut; and 2) the victim inadvertently positioning himself under unsupported roof inby the rib bolts in the side cut area. The location of the arced rib line roof bolts, which narrowed the supported area in the No. 3 Entry, contributed to the accident. The victim's limited mining experience (approximately five weeks total) may have contributed to his inadvertently placing himself in a hazardous location.
ENFORCEMENT ACTIONS
1. A Section 103 (k) Order, No. 7600573, was issued to the operator on August 31, 2001, to ensure the safety of all persons until an investigation could be completed and the mine deemed safe. The order stated, "A fatal accident has occurred at this mine and this order is issued to ensure the safety of anyone in the coal mine. Only company officials, miner's representatives, state officials and MSHA officials are permitted in the coal mine until an investigation has been conducted."
2. A 104 (a) Citation, No. 7627667, was issued to the operator for a violation of 30 CFR 75.202(b) on December 7, 2001. The citation stated, "Persons worked under unsupported roof in the No. 3 Entry of the South Mains working section (MMU-001). On August 31, 2001, a roof bolting machine operator and a miner helper advanced beyond permanent supports in the newly exposed area of a side cut at crosscut No. 6. While the two miners were tending the continuous mining machine trailing cable, a section of roof fell striking both miners. The miner helper was fatally injured and the roof bolter operator received minor injuries."
3. A 104 (a) Citation, No. 7627668, was issued to the operator for a violation of 30 CFR 75.220(a)(1) on December 7, 2001. The citation stated, "The operator failed to follow the roof control plan, approved August 1, 2001, in the South Mains working section (MMU-001). After a new opening was created in the No. 3 Entry/No. 6 Crosscut intersection, the newly exposed area was not supported with permanent roof supports before persons worked in or inby the intersection. On August 31, 2001, subsequent to a mining cycle started in the side cut extending approximately fifteen feet beyond the nearest previously installed permanent supports located in the No. 3 Entry, the continuous miner operator traveled inby the intersection. In addition, the miner helper and a roof bolting machine operator traveled into the newly exposed area and were involved in a roof fall accident. The accident resulted in fatal injuries to one miner and minor injuries to the other person."
Related Fatal Alert Bulletin:
FAB01C17
APPENDIX A
List of persons participating in the investigation:
MID-AMERICA MINING & DEVELOPMENT, INC. OFFICIALS
Raymond F. Parker ............. Mine Manager/SuperintendentMID-AMERICA MINING & DEVELOPMENT, INC. EMPLOYEES
William McNabb ............. General Mine Foreman
Darrel W. Cash ............. Temporary Section Foreman/Continuous Mining Machine OperatorMINE SAFETY AND HEALTH ADMINISTRATION
Levi H. Blair ............. Shuttle Car Operator
James Roberson ............. Roof Bolting Machine Operator
William E. Vetter ............. Coal Mine Safety and Health Specialist(Health)
David L. Weaver ............. Mine Safety and Health Specialist (Training), Educational Field Services
John R. Cook ............. Mining Engineer, Technical Support
Sandin E. Phillipson ............. Geologist, Technical Support
Allen L. Head ............. Supervisory Coal Mine Safety and Health Inspector
John Arrington ............. Coal Mine Safety and Health Inspector
Larry D. Kujawa ............. Coal Mine Safety and Health Inspector
APPENDIX B
List of persons interviewed:
MID-AMERICA MINING & DEVELOPMENT, INC. EMPLOYEES
Darrel W. Cash ............. Temporary Section Foreman/Continuous Mining Machine Operator
Levi H. Blair ............. Shuttle Car Operator
James Roberson ............. Roof Bolting Machine Operator