PDF Version - (Contains All Graphics) Contains all graphics and appendices...
Jump to Overview
DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
COAL MINE SAFETY AND HEALTH
REPORT OF INVESTIGATION
Fatal Shaft Sinking Explosion
January 22, 2003
McElroy Coal Company
(Subsidiary of CONSOL Energy Incorporated)
Cameron, Marshall County, West Virginia
ID No. 46-01437
James K. Oakes
District Manager, District 8, Vincennes, IN
Joseph S. Tortorea
Assistant District Manager, District 2, New Stanton, PA
Richard T. Stoltz
Supervisory Mining Engineer, Technical Support, Pittsburgh, PA
Clete R. Stephan
Principal Mining Engineer, Technical Support, Pittsburgh, PA
Virgil F. Brown
Mine Emergency Unit Specialist, Technical Support, Beckley, WV
Robert A. Penigar
Coal Mine Safety and Health Inspector - Ventilation, District 2, New Stanton, PA
Jerry W. Vance
Coal Mine Safety and Health Specialist - Training, EFS, Morgantown, WV
Mine Safety and Health Administration
Office of the Administrator
Coal Mine Safety and Health
1100 Wilson Boulevard
Arlington, Virginia 22209
Ray McKinney, Administrator
At approximately 1:00 a.m. on January 22, 2003, an explosion occurred inside the McElroy Mine, 5 South #2 Airshaft being constructed by Central Cambria Drilling Company (CCD) for McElroy Coal Company, a subsidiary of CONSOL Energy Incorporated (CONSOL). Six miners were inside the shaft at the time of the explosion. The explosion fatally injured three miners and seriously injured three others. Appendix A is a list of miners on site at the time of the explosion. The explosion also damaged equipment on the work platform and placed dust into suspension.
Prior to the explosion, the miners were attempting to remove corrugated, galvanized steel sheeting (panning) which blocked access to the unventilated water ring being constructed. The miners first partially opened the panning with an axe, and the shift foreman placed a hand-held methane detector into the opening to test for methane. After reading 0.2% methane on his hand-held detector, the foreman directed the mechanic to cut the panning with an oxygen-acetylene torch. The mechanic ignited the torch and started to cut the panning. An explosion occurred when an explosive methane-air mixture contained inside the water ring was ignited by the torch cutting process.
An injured miner exited the shaft after unsuccessfully attempting to assist the two other injured miners. He then re-entered the shaft with a CCD surface worker (Top Man), but they were also unsuccessful in assisting the injured miners and returned to the surface. In response to 911 calls, emergency personnel arrived on site. Two deputy sheriffs, a paramedic, and the Top Man entered the shaft and recovered the two injured miners.
Location and Contract Information
The 5 South #2 Airshaft being constructed for the McElroy Mine (Appendix B) was located on Nauvoo Ridge, approximately 6 miles southwest of Cameron, Marshall County, West Virginia. The contract to construct this 24-foot diameter dual compartment airshaft was awarded to Central Cambria Drilling Company of Ebensburg, Pennsylvania on October 5, 2001 by McElroy Coal Company. A generic cross-sectional view of a shaft is contained in Appendix C. The projected completion date for this shaft was May 2003. Upon completion, the shaft was to be used to provide ventilation to underground areas of the McElroy Mine.
Principal Officers of Central Cambria Drilling Company
The principal officers of CCD at the time of the accident were Glenn R. Williamson, President, Jack Williamson, Vice-President, and Earl Rummel, General Superintendent. CCD has been constructing shafts and slopes primarily in the tri-state area of Pennsylvania, Ohio, and West Virginia since the spring of 1973. At the time of the accident, this shaft was CCD's only active construction operation.
Prior to CCD commencing shaft construction activities, other contractors were used by CONSOL to perform site preparation. CCD began working at the site in December 2001. Between December 2001 and January 2002, the construction and installation of surface facilities were completed, including the installation of the No.1 Hoist. Excavation and construction of the coping and collar commenced in February 2002. Appendix D depicts a plan view of the construction site. Normal shaft sinking construction activities began in mid-February. By mid-May 2002, the shaft had advanced to a depth of approximately 270 feet, where the first of two water rings was constructed. Work progressed until the end of June 2002 when the shaft construction was idled by CONSOL. During this period, the No. 2 Hoist was installed. CCD resumed shaft construction in September 2002. By mid-January 2003, the shaft was developed to a depth of approximately 950 feet and construction of the second water ring was in the final stages of completion.
Gamma ray logging had been performed by a contractor for CONSOL to verify the stratigraphy or geological characteristics at various depths below the ground surface for shaft construction purposes, and the results had been provided to CONSOL in a document dated February 2, 2000 (see Appendix E).
Numerous shale, limestone, and sandstone deposits were identified in the strata log. The explosion occurred at a shaft depth of approximately 950 feet. At this depth the strata log indicated that the shaft was at the bottom of the 30-foot thick Sewickley limestone formation and entering a 10-foot thick shale deposit. Coal seams identified in the strata log, including their approximate thickness and depth, are shown in Table 1. All are potential methane sources in close proximity to the shaft workings.
Normal production days consisted of two12-hour shifts that started at 8:00 a.m. and 8:00 p.m., respectively. The four crew work force alternated day shift and night shift working three days with four days off and then working four days with three days off. The general superintendent and superintendent worked on the dayshift on a regular basis, rotating three days on and three days off. The two night-shift foremen, referred to as Night Walkers, also rotated three days on and three days off. At the time of the accident, CCD employed 33 hourly and 4 salary employees at the site.
Shaft Construction Cycle
The shaft sinking construction cycle consisted of a series of steps (see Appendix F). Holes were drilled into the shaft bottom using a pneumatic Acme Jumbo Drill (jumbo drill). These holes were loaded with explosives, and detonated from the surface with a blasting unit. The loose material was loaded into two cubic yard buckets with an Eimco mucker, hoisted from the shaft bottom, and dumped on the surface during the mucking operation. These activities were repeated for the number of cycles required to achieve an excavation depth necessary for a 25-foot concrete pour and an additional 10 to 15 feet of loose material on the bottom.
The 25-foot concrete pour was completed in a series of four increments, starting at the lowest depth of excavation. The loose material on the shaft bottom was leveled, and panning was installed to create the outer wall of the form to be used to retain the concrete during pouring. Steel reinforcing rods (rebar) were then placed vertically and horizontally at predetermined distances. This was followed by the installation of utility pipes. A 4-piece set of 8-foot steel forms and keyways were bolted into place to create the inner wall of the form used to retain the concrete during pouring. Jacks were installed horizontally, and scaffolding was placed at the top of the forms to be used as a work deck. The concrete was then poured into these forms. This process was repeated two additional times. Each 8-foot steel form pour was referred to by ring number (e.g., Ring #114). To complete the concrete pour, a four piece set of 2-foot high steel forms, called the closure ring, was placed on top of the previous forms and against the surface of the existing concrete shaft lining. When this was filled with concrete, it created a continuous concrete wall connecting the existing concrete shaft lining to the new concrete pour. After the concrete cured sufficiently, the steel forms, scaffolding and jacks were removed in the reverse order of their installation and the shaft construction cycle was repeated.
Water Ring Construction
The water rings were constructed at depths of approximately 270 feet and 950 feet below the surface. See Appendix G for a detailed discussion of water ring construction. Eight to ten feet above the location of each water ring, the excavated diameter of the shaft rough opening was enlarged to allow clearance for support materials. Wire mesh was installed around the perimeter of the shaft rib and bolted. Rows of angled holes were drilled, loaded with explosives, and shot to create each water ring cavity (approximately 3-1/2 feet deep by 5-1/2 to 7 feet high). Wire mesh was installed against the roof and ribs of each cavity which were then bolted and gunited. Horizontal holes (weep holes) were drilled into the strata at floor level around the perimeter of the water ring cavity to provide drainage into the ring.
After additional mucking was completed to a depth of approximately 26 feet, the first set of 8-foot steel forms (Bottom Ring) was installed and the concrete was poured as described in Appendix F. As a part of this pour, the floor of the water ring was formed and a trough was created in the concrete to allow water drainage. Panning material was placed horizontally and vertically and fastened together to serve as the back wall of the form for the concrete pour (see Appendix G). Once this panning was installed, the water ring cavity located behind the panning would be isolated from the shaft ventilation.
Rebar were installed and a steel mandoor frame was then placed in front of the panning and attached to the rebar. The mandoor frame was installed to allow future access into the water ring. The second and third set of steel forms (middle and top rings), and the closure ring were then installed as described in Appendix F, and were filled with concrete in sequence to complete the cycle.
After removal of the closure, top, and middle rings, four 1.75-inch diameter ventilation holes were drilled opposite the mandoor frame through the concrete shaft lining into the water ring. During construction, these holes were intended to be used to detect the presence of methane and to ventilate the water ring.
EVENTS LEADING TO THE ACCIDENT
On January 11, 2003, construction of the second water ring began (see Appendix H). Between January 11th and January 14th, rows of holes were drilled into the shaft rib at pre-selected angles. The last rows of holes were loaded with explosives and shot on January 15th, creating the water ring cavity. The material was removed as a part of the mucking operation. Sections of wire mesh were attached to the ribs and roof of the water ring cavity, the roof was bolted and gunite was applied to the water ring cavity surfaces by January 17th. On January 18th, panning, rebar, utility pipes and the steel forms for Ring #114 were installed. On January 19th, concrete was poured on the 8:00 a.m. shift. The panning, mandoor frame, C channels and cables were installed during the following shift. On January 20th, during the 8:00 a.m. shift, additional panning and rebar were installed. At this time, the water ring cavity became isolated from the shaft ventilation system. During this shift, the steel forms for Ring #113 were installed and the concrete was poured. During the 8:00 p.m. shift, the forms for Ring #112 were installed and the concrete pour was started. On January 21st, the 8:00 a.m. crew completed pouring Ring #112. The crew installed the four-piece closure ring and completed pouring the concrete that connected the new concrete pour to the existing concrete shaft lining. The dayshift crew performed work on the surface for the next six hours while the concrete began to cure. Near the end of the shift, the crew re-entered the shaft and began removing pieces of the closure ring.
DESCRIPTION OF THE ACCIDENT
Night Shift Foreman Richard Brumley arrived on site after 7:00 p.m. on January 21, 2003. While preparing for the start of his shift, he met Superintendent Larry Whyte in the office. Whyte discussed the work to be performed, indicating that the dayshift crew had completed pouring concrete and had removed the first two sections of the closure ring. They discussed removing the remaining forms and drilling ventilation holes through the concrete into the top of the water ring. Whyte made a sketch to show Brumley where and how to drill the ventilation holes. They also discussed using an axe to cut an opening in the panning that blocked access into the water ring. Whyte cautioned Brumley about the presence of methane in the water ring and advised him to conduct an examination for methane. In addition, Whyte directed Brumley to use the torch to finish cutting out the panning if methane was not detected. Brumley advised Whyte that he (Brumley) had conducted the preshift examination for his oncoming shift.
Just before 8:00 p.m., the dayshift crew exited the shaft and Lead Miner (Person who directed activities in the shaft in the absence of management personnel) Paul Price discussed the status of the work that had been completed on his shift with Brumley. Based on previous experience and knowledge about methane, Price also advised Harry Roush, III, oncoming shift Lead Miner, to be careful during his attempt to cut away the panning blocking access to the water ring because there would be methane trapped behind it.
Brumley assigned Drillers Benjamin Bair and Richard Mount to work with Roush III to remove the steel forms. Driller Aaron Meyer was assigned to assist Top Man Jack Cain to clean and oil the forms as they were removed from the shaft. Mechanic David Abel was assigned to perform maintenance on an Eimco mucker since mucking would be performed after all the forms were removed.
Shortly after 8:00 p.m., Roush III, Bair, Mount and Brumley climbed into the bucket. Hoist Operator Denver Jordan lowered the bucket into the shaft and work commenced. After the work of removing the forms began, Brumley exited the shaft and entered the office to perform paperwork. Roush III, Bair, and Mount removed the last two sections of closure ring and patched areas of the shaft wall with concrete. They removed the three pieces of scaffolding used to create the work deck and the jack that supported the top of Ring #112. Roush III, Bair, and Mount then completed the removal of Ring #112.
At approximately 10:00 p.m., Brumley re-entered the shaft with a pneumatic tool to drill four ventilation holes. These holes were drilled through the concrete shaft lining and panning into the top of the water ring. After the holes were drilled, Brumley conducted a methane examination in the shaft at the entrance of the holes using the hand-held CSE 102 detector and then exited the shaft with the pneumatic tool. When Brumley arrived on the surface, Meyer overheard Brumley state that he had taken a methane reading and had detected methane. Meyer recalled hearing Brumley state that he had measured "four" (The MSHA Investigators could not determine whether "four" indicated 4% or 0.4% methane. Meyer only remembered hearing Brumley say "Four". Brumley was advised by counsel during his interview not to discuss any of the activities that took place on the evening of the explosion and the instrument he used to conduct the examination was not able to store data.) at the ventilation hole(s).
Within the next couple of hours, Roush III, Bair and Mount removed the next set of forms (Ring #113) and had them hoisted out of the shaft. After Abel finished servicing the Eimco mucker, he assisted Meyer and Cain in cleaning and oiling the forms.
At approximately 12:00 a.m., Roush III called from the shaft bottom and requested a pneumatic jack hammer (chipper) and axe. Brumley instructed Cain to load the tools into the bucket. Abel checked the torch cutting assembly and tanks which were also loaded into the bucket. At approximately 12:30 a.m., Brumley, Meyer, and Abel climbed into the bucket and entered the shaft.
Roush III, Meyer, and Bair chipped the concrete from inside the mandoor frame to access the panning. One of the miners used an axe to create an initial opening in the panning. The opening was approximately one-foot long by 3-inches wide and was located towards the right-hand side of the frame. Brumley placed the CSE 102 detector into the opening and measured 0.2% (Witnesses indicated during their interviews that they were told the morning of the explosion by Meyer that the methane reading was 2.0%. However, during Meyer's interview, he stated that the reading was 0.2% methane.) methane. Brumley then instructed Abel to cut the panning. Meyer moved away from the mandoor. Abel assembled and ignited the torch. At approximately 1:00 a.m., an explosion occurred as Abel started cutting through the panning with the torch.
The explosion force exited the water ring through the mandoor frame. Flames shot across the shaft to the opposite wall and continued left and right around the shaft. Meyer, who was positioned to the right side and away from the mandoor, covered his face and dropped to the work deck. When Meyer no longer felt heat, he took his hands away from his face and looked around. He had very limited visibility because of the dust in suspension. Meyer walked toward the center of the shaft and found Brumley who was trying to sit up. Meyer helped Brumley move toward the bucket, however, Brumley was not able to board the bucket due to his injuries.
At the time of the explosion, Cain was in the No. 1 Hoist house with Jordan. They heard the explosion and saw dust rise out of the shaft. The force of the explosion broke a window in the No. 2 Hoist house. Cain ran to the shaft, where he shouted to the miners; however, he did not receive a response.
Believing the fan was off because of the dusty conditions, Meyer located the bell pull cord and signaled Jordan to turn on the fan. According to interview statements of Cain and Jordan, the fan was already operating. Meyer then found the pager phone and instructed Jordan to hoist the bucket out of the shaft, empty the bucket, and send Cain back into the shaft to assist him with the injured miners. Meyer asked Jordan to notify him when the bucket was being lowered because he could not see.
Jordan raised the bucket out of the shaft and placed it on the ground. He then entered the office where he and Cain called 911 to report the explosion. After the 911 call was made, Jordan exited the office and observed that the bucket assembly was damaged. He decided to use the No. 2 Hoist and bucket for transporting Meyer and the other injured miners.
Meanwhile, Meyer began looking for the other miners. He again found Brumley who was trying to move toward the center of the shaft. Meyer helped Brumley move to the shaft wall and walked around the shaft searching for the other miners. He found Roush III lying on his back and could not detect a pulse. Meyer located Bair, who was also trying to pull himself toward the center of the shaft. Bair appeared to be in shock and was not responsive to Meyer. After Bair, Meyer found Mount and could not detect a pulse. He was unable to locate Abel.
Jordan notified Meyer that he was lowering the bucket into the shaft. When the bucket was near the bottom, Meyer used the bell pull cord to assist Jordan in placing the bucket on the deck. Meyer tried to help Brumley and Bair enter the bucket but was unsuccessful due to the extent of their injuries. Meyer then climbed into the bucket and signaled Jordan to raise the bucket out of the shaft.
On the surface, Meyer told Cain that Brumley and Bair were injured and needed help. He also told Cain about the status of Roush III and Mount and that he could not locate Abel. Meyer and Cain obtained the backboard, climbed into the bucket and entered the shaft. When they reached the work deck, they were unable to help either Brumley or Bair into the bucket because of the extent of their injuries and Meyer's trauma. Cain and Meyer exited the shaft.
RESCUE AND RECOVERY OPERATIONS
In response to the 911 calls, Marshall County Deputy Sheriffs Brent Wharry and Steven Cook, along with members of area volunteer fire departments and other medical personnel arrived at the shaft site at about 1:40 a.m. Rescue personnel determined that they did not have the proper training to enter the shaft and requested that mine rescue teams be brought to the shaft to recover the injured miners. Discussions took place about the condition of the injured miners and the need to recover them immediately. At about 2:00 a.m., Cain, Wharry, Cook, and Donald Kline, a Tri-State Ambulance Service paramedic, entered the shaft. They assisted Brumley into the bucket, placed Bair on a back board and then placed the back board across the rim of the bucket. They boarded the bucket and were raised to the surface. Bair and Brumley were transported by helicopter to the Mercy Hospital burn unit in Pittsburgh, Pennsylvania. Meyer was transported by ambulance to Reynolds Memorial Hospital in Glendale, West Virginia, where he was treated and released.
At approximately 1:50 a.m., a CONSOL employee who overheard 911 conversations about an explosion on CONSOL property contacted the 911 control center to obtain additional information. CONSOL corporate personnel were informed that an explosion had occurred at the shaft sinking operation of the McElroy Mine resulting in possible casualties and that mine rescue teams were needed. CONSOL corporate safety personnel contacted and mobilized their Enlow Fork and Blacksville #2 mine rescue teams. CONSOL also notified the 911 control center at 2:18 a.m. that these two mine rescue teams had been mobilized.
Due to an ongoing mine fire recovery, the mine rescue teams were located at Mine 84 operated by Eighty-Four Mining Company, a subsidiary of CONSOL located in Eighty Four, Pennsylvania. Charles Pogue, Mine Safety and Health Administration (MSHA) Mine Emergency Unit (MEU) trainer was stationed in the Mine 84 recovery operations command center. CONSOL personnel informed him that an explosion had occurred at the shaft sinking operation at the McElroy Mine and that there were possible casualties. Pogue then notified Ronald Costlow, MSHA MEU Supervisor. At approximately 2:30 a.m., Costlow notified William P. Knepp, Acting District Manager for District 3, who notified MSHA headquarters and other personnel. District 3 personnel were dispatched to the site. MSHA, West Virginia Mine Health, Safety & Training (WVMHS&T), CCD, CONSOL, and United Mine Workers of America (UMWA) representatives, the two mine rescue teams, and various emergency personnel arrived at the site over the next several hours.
At approximately 9:50 a.m., two Industrial Scientific, Model TMX-412 detectors were hung from the bucket and lowered into the shaft to evaluate the shaft atmosphere before personnel were allowed to enter the shaft. When the bucket was returned to the surface, the instruments indicated peak readings of 0.0% methane, 20.9% oxygen and zero parts per million (ppm) carbon monoxide. Therefore, it was determined that mine rescue teams would not be needed to recover the victims.
At approximately 10:00 a.m., Medical Examiner John Carson, Assistant Medical Examiner Mitch Corley, WVMHS&T Inspector Colin Simmons, MSHA District 3 Inspector Ronald Tulanowski, and General Superintendent for CCD Earl Rummel entered the shaft to assess the accident scene and recover the victims. Upon arriving at the work deck, Tulanowski and Simmons exited the bucket to examine the area. Air bottle samples were collected at the center of the shaft and inside the water ring, just beyond the mandoor frame. The results of these bottle samples were 0.02% and 0.31% methane, respectively. After two of the victims were brought to the surface, Whyte replaced Rummel during the recovery of the third victim. By approximately 12:00 p.m., all three victims had been brought to the surface.
INVESTIGATION OF THE ACCIDENT
The Administrator for Coal Mine Safety and Health directed that an investigation be conducted by a team consisting of personnel from MSHA Districts 2 and 8, Education Field Services, Pittsburgh Safety and Health Technology Center, and the Office of the Solicitor. James K. Oakes, MSHA District 8 Manager, was assigned as the accident investigation team leader.
On January 23, 2003, the team assembled at the MSHA St. Clairsville, Ohio Field Office and began the investigation. Preliminary information and records were obtained from MSHA, CCD, and CONSOL. Twenty-one formal interviews were conducted by representatives of the MSHA investigation team and transcripts were prepared. Most of these interviews were conducted in the presence of representatives of CCD, CONSOL, WVMHS&T and the UMWA. Appendix I is a list of persons interviewed on a non-confidential basis and Appendix J lists persons who participated in the investigation. Twelve additional interviews were conducted by MSHA personnel. Other contacts were made and information was obtained from persons having relevant information. Pertinent records were obtained and reviewed during the course of the investigation. Physical evidence was mapped, collected, examined, and/or tested, as necessary (see Appendices K, L and M). Selected photographs are shown in Appendix N.
Interaction between Central Cambria Drilling Company and CONSOL
Subsequent to a 1992 shaft explosion involving an independent contractor at its Blacksville No. 2 Mine, CONSOL entered into a cooperative agreement with MSHA in 1996 to improve safety for contractor employees working at CONSOL mines. In this agreement, CONSOL was to more closely review contractor safety background and assign a Site Superintendent to monitor contractor activities at its sites. CONSOL was also to conduct semi-annual safety audits. When the investigation team requested copies of all safety records pertaining to CCD, CONSOL indicated that the only records available were the daily work sheets from CCD. The investigation team obtained copies of the work sheets from CCD during the investigation.
With respect to CONSOL monitoring the shaft construction, CONSOL Project Engineer Michelle O'Neil performed oversight duties at the CCD McElroy Mine, 5 South #2 Airshaft sinking operation. She was supervised by Van Pitman, Manager of Engineering Services. O'Neil was responsible to oversee work performed by CCD to assure it fulfilled its contractual obligation to McElroy Mine in the construction and development of the 5 South #2 Airshaft. O'Neil interacted with Rummel and/or Whyte in matters regarding the development of the shaft. O'Neil determined where both water rings would be installed. She also monitored construction activities and reviewed CCD safety records at the site during periodic visits. However, she did not participate in the day-to-day shift examinations at the site.
Central Cambria Drilling Company Management Structure
The general superintendent had overall responsibility at the shaft site, including but not limited to, planning, purchasing, scheduling, health and safety, training, and interaction with CONSOL. The superintendent reported to the general superintendent and assumed these responsibilities in the absence of the general superintendent. They had direct responsibility over the dayshift crews. The night shift foremen also reported to the general superintendent or the superintendent on their respective work shifts, and had responsibility over the night shift crews. The general superintendent, the superintendent and the night shift foremen were responsible for conducting and recording the required examinations and for complying with the approved Shaft Sinking Plan. A lead miner was assigned to each crew to direct activities inside the shaft and to convey instructions from management. Appendix O depicts the management structure for CCD at the time of the accident.
Injury Incidence Rate History
With respect to the injury history for CCD, Table 2 shows the Non-Fatal Days Lost (NFDL) and All Injury Incidence Rate with the comparable national rates for contractors at coal mines. The All Injury Incidence Rate is a compilation of the Fatal, NFDL, and the No Days Lost (NDL) incidence rates. Preparation plant and office workers are excluded. The table shows the incident rates for the years 2001 and 2002. The accident occurred during the first quarter of 2003.
An MSHA Regular Safety and Health Policy Inspection (BAE) of the shaft had been conducted on April 22, 2002. There were no outstanding citations at the time of the accident.
Training required by Title 30, Code of Federal Regulations (CFR), Part 48, does not include shaft-sinking workers. Operators are required by 30 CFR, Section 77.107 to provide a program to train and retrain qualified and certified persons such as hoist operators and persons who conduct examinations for methane and oxygen deficiency. However, CCD did not have an approved training plan as required by 30 CFR, Section 77.107-1. Investigation interviews and available training records indicate that CCD did provide site specific hazard and task training as well as annual refresher training for their employees. Neither the failure of CCD to have an approved training plan nor the training provided to their employees was found to be a contributing factor to the explosion.
Shaft Sinking Plan
The Shaft Sinking Plan (Plan) in effect at the time of the accident was approved by MSHA on January 29, 2002. The shaft was described as a 24-foot inside diameter, round, concrete-lined, two-compartment airshaft of 1,018 vertical feet with a minimum wall thickness of 9 inches. The shaft was to be constructed using conventional shaft sinking methods (drill-shoot-muck), and the estimated construction time was 12 months.
The Plan addressed a variety of requirements, including but not limited to, ventilation, examinations for methane, and burning and welding underground. At least 6,000 cubic feet per minute (cfm) of air was required at the inby (shaft bottom) end of the ventilation ductwork or tubing. The required fan capacity was 7,000 cfm, and the fan could be operated in either a blowing or exhausting mode. The tubing or ductwork was to be maintained within 40 feet of the shaft bottom when operating the fan in a blowing mode. When the fan was operated in an exhausting mode, the tubing or ductwork was to be maintained within 10 feet of the shaft bottom. An examination of the ventilation equipment was required before each shift. The quantity of air in the shaft was to be measured at least once each day by a certified person and the results recorded. The fan was to be operated continuously when miners were underground except while aligning forms, installing or working on ventilation tubing, or plumbing the shaft. During these activities, the fan could be shut off for a maximum of 15 minutes.
The Plan addressed specific requirements for burning and welding in the shaft. All persons who performed burning and welding were required to be trained for such work. No records of this training were required to be maintained nor were any records found. Under the Plan, burning and welding in the shaft were to be performed in fresh air only. A qualified person was required to make an examination for methane before and during burning and welding operations. No burning or welding was allowed when 1.0% or more methane was detected.
In addition, the Plan contained the following provisions:
CONSOL supplied 4,160-volt 3-phase power to the shaft site. Power was distributed through a 750 kilovolt-amperes (kva) load center. The load center provided 480-volt three phase alternating current (ac) and 220/110-volt single phase power for surface facilities and equipment used in the shaft.
A 60-hp, 480-volt fan was used to ventilate the shaft. The remote start/stop switch for the fan was located in the No. 1 Hoist house.
A 220-volt single phase, �-hp submersible pump was located in the first water ring. Four single #10 American Wire Gauge (AWG) conductors supplied power to the pump. These conductors entered the shaft through an 8-inch PVC pipe located within the concrete shaft wall and extended to the first water ring. The power conductors to the pump were found disconnected on the surface.
Blasting wires entered the shaft through another 8-inch PVC pipe located within the concrete shaft lining. The wires extended to the bottom of the shaft. The wires were found shunted on the surface and were not in use at the time of the explosion.
A General Electric (GE) 110-volt, Class I, Division I lighting fixture was located in the shaft approximately 35 feet above the work deck. Power was supplied through a #10/3 conductor-type SO cable that originated in the No. 2 Hoist house. This lighting fixture was in service at the time of the explosion.
A Femco-Gulton permissible mine phone was located approximately 42 inches above the work platform. The phone was in service at the time of the explosion. All phones connected to the system were permissible.
The shaft was initially ventilated with a 30-hp Hartzell fan attached to 18-inch diameter, metal ventilation tubing which extended down the shaft. Flexible 18-inch diameter tubing was attached to the end of the metal tubing to meet the ventilation requirements of the Plan. CCD recognized that the ventilation induced by the 30-hp fan was becoming marginal and would not be capable of providing the 6,000 cfm required in the Plan as the depth of the shaft increased. On October 14, 2002, the 30-hp fan was replaced with a 60-hp Hartzell fan, Series 56-33-BU2, operating at 3,500 revolutions per minute (rpm). However, the required air measurements recorded by CCD on October 14th and 15th indicate that the air quantity at the end of the tubing near the bottom of the shaft did not change significantly, increasing from 6,480 cfm to 6,559 cfm.
The depth of the shaft was advanced approximately 350 feet from October 14, 2002 until January 21, 2003. During this period of time additional metal tubing was installed to meet the Plan ventilation requirements. The shaft continued to be ventilated using the 60-hp fan. Between October 12, 2002 and January 21, 2003, inclusive, CCD recorded air quantity measurements that were required to be taken at the inby end of the tubing. The recorded measurements ranged from 6,400 to 9,000 cfm (see Appendix P). There are several factors that affect air quantity measurements, including but not limited to, using proper instruments, taking air quantity measurements at the proper location, maintenance of the ventilation system, length of tubing, and reading the instrument (anemometer) properly. According to interviews, anemometers were used at the proper location. In addition, CCD personnel demonstrated to MSHA personnel that they knew how to use an anemometer properly.
On January 21, 2003, the fan continued to be operated in a blowing mode. CCD records indicate that a quantity of 8,720 cfm was measured at the inby end of the tubing on that date. On February 5, 2003, measurements were conducted by MSHA personnel to determine if CCD had been in compliance with the Plan ventilation requirements. Air quantity measurements were conducted at three locations. An air quantity of 9,400 cfm was determined in the duct between the fan and the shaft collar. Air quantities measured at the inby end of the metal and flexible tubes were 4,900 cfm and 3,640 cfm, respectively, which did not meet the Plan requirement of 6,000 cfm. Also, a distance of approximately 48 feet was measured between the inby end of the flexible tubing and the shaft bottom below the work platform (top of muck pile). The Plan stipulated a maximum distance between these two points of 40 feet.
After being advised by MSHA investigators that the air quantity measured at the inby end of the tubing did not meet the Plan minimum requirements, CCD requested permission to work on the shaft ventilation system. The 103(k) order was modified on February 11, 2003, to allow them to perform this work. Between February 11th and February 12th, CCD attempted to increase the ventilation quantity to meet the Plan requirements. However, CCD was still unable to obtain the Plan minimum air quantity with the 60-hp fan. On February 12th after CCD's attempts to increase the quantity, MSHA investigators measured 4,810 cfm at the inby end of the metal tubing. At this point, CCD submitted revisions to the Plan to include a 75-hp Hartzell fan, Series 56-48-BV3, designed to operate at 1,780 rpm. On February 13, 2003, after the larger fan was installed, the investigation team measured 6,670 cfm at the inby end of the tubing.
Welding and Cutting
Welding was not performed inside the shaft. If equipment required welding repairs, the equipment was hoisted out of the shaft and repaired on the surface.
Burning or cutting with the torch was performed as needed inside the shaft. The torch was used to cut rebar and to gain access into the water ring after the concrete forms were removed. When torch use was required, the torch and accessories were loaded in the bucket and lowered into the shaft. This welding and cutting equipment was not stored inside the shaft.
The process of burning and cutting inside the shaft, such as the removal of the panning that blocked access into the water ring, required only two persons to perform the operation, one to monitor the atmosphere and the other to perform the cutting operation. If this had been the work practice on the morning of the accident, the number of miners exposed to the hazards would have been reduced.
Just prior to the accident, the mechanic checked the torch before taking it into the shaft. The investigation revealed that the torch cutting assembly, including the valves on both the oxygen and the acetylene tanks, were damaged as a result of the explosion. Portions of the torch were tested by MSHA Approval and Certification Center (A&CC) and the results are contained in Appendix Q.
Search for Smoking Articles
CCD records indicated that searches were being conducted as required in the Plan. While many miners recalled that smoke searches had been conducted, a few miners said they had never been searched. In addition, evidence collected from the bottom of the shaft during the investigation included two pieces of a Camel Ultra Lights' brand cigarette box.
On February 5, 2003, air samples were collected to determine the methane liberation in the shaft. A methane liberation rate of 425 cubic feet per day (cfd) was calculated at a location approximately 48 feet from the shaft bottom. Methane samples were also collected in the water ring and showed methane concentrations ranging from 0.0090% to 0.0150% (see Appendix R). These values, along with bottle samples collected after the explosion, show that methane was being liberated in the shaft and in the water ring. The weep holes could have provided a conduit for additional methane to migrate from the strata into the water ring.
Barometric Pressure Readings
Barometric pressures are recorded at various stations throughout the United States. The station closest to the shaft site was identified to be Wheeling, West Virginia. This information is available through several sources and was obtained from an internet source identified as wunderground.com. Data for a 24-hour period, spanning the 12-hour period before and after the time of the explosion was obtained and reviewed. The information indicated that a low pressure weather system had passed through the area which resulted in a barometric pressure drop from approximately 11:30 p.m. on January 21, 2003 to 1:00 a.m. on January 22, 2003 (see Appendix S). The strata gases would have been negligibly affected by this slight pressure drop. Therefore, the barometric pressure drop did not materially contribute to the rate of methane liberation from the adjacent strata into the water ring. However, it would have had some affect on the body of methane confined between the panning and the shaft rib by causing the body of methane to expand.
Effects of Heat of Hydration
As the shaft was constructed, an air space was formed between the panning and the shaft rib. The air space existed the entire length of the shaft and was isolated into three parts: from the hitch point near the collar of the shaft to the floor of the first water ring, from the floor of the first water ring to the floor of the second water ring, and from the floor of the second water ring to the bottom of the concrete shaft lining. Since the shaft had been constructed through three identifiable coal seams and probably other methane bearing strata between the first and second water rings, methane would migrate from the strata into the associated air space between the two water rings. Methane would likely stratify at the high point of each air space because it has a specific gravity of 0.555. As a result, the top of each air space would continuously be filling with methane and the interface between the methane and air would move downward.
When the inby end of the concrete shaft lining was opened to the atmosphere during shaft construction, methane-air mixtures near the bottom of the concrete shaft lining would be flushed out by the passing ventilation currents. Therefore, there would be a gradient of methane content that ranged from nearly100% at the top of the air space to nearly zero at the bottom of the air space, which was open to the bottom of the concrete shaft lining. The air space became a closed system during each concrete pouring cycle. It was isolated from the atmosphere inside the shaft once all the panning was installed for the 25-foot pour and remained isolated until the sand and gravel mix and starter ring were removed. During this isolation period, an increase in total methane would occur in the air space.
The heat of hydration generated from the concrete curing process would create natural ventilating pressure (NVP). The NVP would induce air movement in the air space between the two water rings. This heat would also create convection currents that would mix the warmer air at the bottom with the cooler, methane enriched air above. This would result in a slightly increased methane enriched air mixture that would be circulated back to the water ring. At this point, it would be further heated by the concrete curing and again rise. In addition to being warmed, the air would have a lower specific gravity since it had mixed with methane from above. With the lower specific gravity, the reheated air would displace methane enriched air from a higher point in the air space. This process would continue as long as there was an ambient temperature difference in the air space caused by the concrete curing. Because of this methane and air mixing process, various methane concentrations would be present within the water ring. The quantity of air contained in the second water ring was calculated to be approximately 2,300 cubic feet. The volume of the air space between the two water rings was estimated to be approximately 7,650 cubic feet, over three times the volume of the water ring. Using formulas based on NVP, the period of time to circulate 100% of the water ring air volume was calculated to be less than 10 minutes. Prior to the explosion, the water ring was isolated and unventilated for approximately 26 hours. This provided sufficient time for an explosive methane-air mixture to develop.
Methane in Pipes
Four pipes were installed within the concrete shaft lining and extended from the collar to the shaft bottom (see Appendix C). Three of the pipes were 8-inch diameter PVC pipes and the fourth was a 6-inch diameter steel pipe. These were intended to be used for mine utilities and de-watering. Methane was detected in the pipes on February 5, 2003. Monitoring and testing were conducted to determine the source of the methane. It was determined that methane from the adjacent strata was entering the pipes through openings and cracks in the pipes and concrete shaft lining (see Appendix T).
There were three methane detectors on site at the time of the explosion. Two of the detectors were Passport FiveStar Personal Alarm instruments (FiveStar) manufactured by Mine Safety Appliance Company (MSA). Each of the FiveStar instruments was equipped with data storage capability. The third methane detector was a CSE Corporation Model 102 Portable Methane Detector (CSE 102). The CSE 102 detector does not have data storage capability. A FiveStar and the CSE 102 detectors were found among Brumley's personal items during the investigation. The other FiveStar was found in the office located at the shaft site.
A&CC inspected and tested the MSA FiveStar instruments (see Appendix U). It was determined that these units were not manufactured in accordance with their approved design. However, there is no evidence that these discrepancies could have produced conditions that would have provided enough energy to ignite a flammable methane-air mixture.
CCD records indicated that Richard Lewis, Safety Director until November 2002, last calibrated the two FiveStar instruments on October 22, 2002. The data stored in memory showed that the methane sensor in each instrument was last calibrated on October 21, 2002. The data also indicated that the FiveStar found in Brumley's jacket pocket was last activated for less than one minute at 8:11 p.m. on January 21, 2003. Therefore, this instrument was not used to perform the required examinations when the accident occurred.
No record was found that the CSE 102 instrument had been calibrated. The CSE 102 detector was inspected and tested by A&CC (see Appendix U). Several permissibility discrepancies were identified, but were not significant with respect to being an ignition source. No definitive determination on the operating status of the instrument at the time of the accident could be verified because the instrument could not store data. However, interview statements taken during the investigation indicated that this instrument was used to test for methane for the January 21, 2003, 8:00 p.m. preshift and examinations conducted in the shaft during the shift. Tests showed that the instrument was not properly calibrated to detect methane within the limits of accuracy required by the MSHA approval process. When a 2.0% methane-in-air mixture was applied to the instrument, it read 1.6% methane. This equates to a 20% percent error, which would cause the instrument to indicate a lower methane concentration in the atmosphere than what was actually present.
CCD had been constructing shafts and slopes since the spring of 1973. The certified supervisory officials had extensive experience constructing shafts through methane bearing strata and they demonstrated knowledge to MSHA of the properties of methane. Preshift and on-shift examinations of the shaft are required under 30 CFR, Section 77.1901. Examinations must be conducted prior to cutting and welding as required by 30 CFR, Section 77.1916(c). These should include tests for methane in all areas that could be affected by these activities, including any location where sparks could travel. CCD certified and/or qualified persons were responsible for conducting these examinations. After the accident, CCD management personnel demonstrated that they knew how to perform examinations for methane.
The Plan required that the ventilation apparatus be examined before each shift, that the air quantity in the shaft be measured daily by a certified person, and that the results be recorded. The quantity of air in the shaft is required, under 30 CFR, Section 77.1911(a), to be measured daily by a certified person and the results of such examinations be recorded in a book. After the accident, CCD management personnel demonstrated that they knew how to properly use airflow measuring equipment.
After conducting air measurements, the investigation team found that the air quantity at the inby end of the ventilation tubing did not meet the Plan requirements, and in fact, was only 61% of the ventilation requirement. The investigation team further determined that the metal duct was intact, the flexible tubing was not damaged by the heat of the explosion, and a 4-inch space between the flexible tubing and the metal duct occurred during installation. In addition, the fan was examined and found not to be damaged by the explosion. As stated previously, CCD was allowed to perform work on the shaft ventilation system on February 11th in an attempt to increase the air quantity, but was unable to increase it to the required 6,000 cfm minimum at the inby end of the tubing. Therefore, the measured quantities obtained during the investigation typified the measured quantities that CCD should have found and recorded. These findings revealed that the air quantities entered in the record books by CCD management personnel did not accurately reflect the air quantities in the shaft prior to the explosion (see Appendix P).
Potential Ignition Sources
An explosion requires the suspension of a fuel within a confined space with sufficient quantities of oxygen present. Also, the fuel must be exposed to significant levels of heat or energy from an ignition source. A determination of the fuel is vital in establishing potential ignition sources because ignition characteristics vary with different fuels. The fuels considered for the explosion that occurred included acetylene, explosives, and methane.
Acetylene from the tank at the bottom of the shaft at the time of the explosion was eliminated as the fuel source for several reasons. The specific gravity of acetylene is 0.908, indicating lighter than air characteristics. Acetylene would not accumulate in the bottom of the shaft because of its tendency to rise in the shaft. The ventilating air would also serve to remove acetylene from the shaft. Acetylene would not be expected to accumulate within the water ring due to its lack of exposure to this confined area. Ignition of a uniform acetylene accumulation would cause similar effects on all individuals within the confines of the shaft. However, the six employees who were working in the shaft at the time of the explosion were subjected to a wide variety of forces, which originated within the water ring. Since the equipment had been checked prior to taking it into the shaft, it should have been in good operating condition and no leakage of acetylene should have occurred.
Explosives were eliminated as the fuel because an evaluation of the work deck and the bottom of the shaft did not reveal any evidence indicating an unplanned detonation of an explosive charge. Explosives were not found during the mapping phase of the investigation. Explosives were not necessary for the work that was being performed at the time of the explosion.
Methane did provide the fuel for the explosion. Evidence indicates that the explosion was initiated within the water ring near the bottom of the shaft. The water ring was separated from the shaft and was not ventilated for a period of approximately 26 hours immediately prior to the explosion. The presence of methane in the water ring was verified through the analysis of bottle samples taken during the recovery of the victims and during the investigation.
Methane explosions can cause pressures resulting in the damages observed during the investigation. The volume of the water ring is sufficient for substantial accumulations of methane to occur within its explosive range. The confinement of the water ring would likely result in pressure piling with its associated increased pressures. The mandoor between the water ring and the shaft allowed directional forces to propagate from the water ring into the shaft.
As methane from the surrounding strata entered and mixed with air trapped within the unventilated water ring, the methane-air mixture eventually entered its explosive range between 5% and 15%. Based on the observed damage caused by the explosion, methane within its explosive range most likely was present in portions of the water ring, including the vicinity of the mandoor frame.
Methane can be ignited by temperatures of about 1,000 degrees Fahrenheit. The minimum ignition energy for methane is about 0.3 millijoule. This amount of energy is only about 1/50 of the static electric charge accumulated by a person walking on a carpeted floor in a dry atmosphere. Potential ignition sources are those sources that have temperatures or energies exceeding the minimum ignition requirements for methane. The potential ignition sources at the bottom of the shaft or in the water ring were as follows:
1. Mine Phone
MSHA personnel removed the battery from the permissible Femco mine phone during recovery operations. This mine phone was examined and was found to be in safe condition. The battery was reinstalled during the investigation and the phone was operational. The mine phone was eliminated as an ignition source because there was no evidence to indicate that an ignition was caused by its operation and it was not located in close proximity to the mandoor opening into the water ring where the explosion occurred.2. Striker for Torch
The striker for igniting the torch was found in the water ring. The striker could ignite methane. However, it would have been used in the fresh air of the shaft and would not have been exposed to explosive concentrations of methane. Statements indicated that the striker was used without incident just prior to the explosion. It was eliminated as an ignition source.3. Light Fixture
A light fixture, suspended along the shaft wall approximately 35 feet above the work deck, was used to illuminate the work area at the bottom of the shaft. Explosive methane concentrations would not have occurred at this location due to ventilation in the shaft. The lighting fixture was eliminated as an ignition source.4. Axe
The intended function of the axe was to create an opening in the panning covering the mandoor frame. Although there is a remote possibility that this action in itself could ignite methane, the examination and testing conducted by A&CC indicated that it was highly unlikely that the axe striking the panning would create a spark capable of igniting a methane-air mixture. Furthermore, statements revealed that this opening into the panning occurred without incident just prior to the explosion. The axe was eliminated as an ignition source (Appendix U).5. Electrical Conductors
There are no indications that electrical conductors provided the ignition source for the explosion.6. Smoking Articles
Employees of CCD were aware that smoking articles were not permitted in the shaft. Many of the miners involved did not smoke. CCD records indicate that smoking articles were not found on anyone entering the shaft. However, some miners stated that they didn't recall being searched. Two pieces of a cigarette box were found at the bottom of the shaft by the mapping team during the investigation. No physical or interview evidence showed that the explosion was caused by smoking articles or activities. Smoking was eliminated as an ignition source.7. Pneumatic Chipper
The pneumatic chipper was used to remove excess concrete from within the mandoor frame. The chipper was not in use at the time of the explosion and was eliminated as an ignition source.8. Pneumatic Wrench
The pneumatic wrench was not exposed to the explosive methane concentrations in the water ring. It was eliminated as an ignition source.9. Cap Lamps
The cap lamp assemblies were tested by A&CC. Testing indicated that the assemblies were not an ignition source (Appendix U).10. Gas Detectors
Gas detectors were tested by A&CC. Testing indicated that the detectors were not an ignition source (Appendix U).11. Torch
One function of the torch was to cut through the panning that blocked access into the water ring. Based on the evidence, the flame of the torch, molten metal, or the superheated surface of the panning ignited an explosive methane-air mixture in the water ring (Appendix Q).Description of Explosion
Before the panning was installed, the water ring cavity was common with the shaft. Methane entering the water ring cavity was being diluted and removed. During the 26-hour period after the panning was installed, the water ring was isolated from the ventilation in the shaft. Additional methane entered the water ring during this time. The methane was not removed because the water ring was unventilated. Bottle samples collected inside the water ring during the investigation confirmed that methane was entering the water ring prior to the explosion.
Four 1.75-inch diameter ventilation holes were drilled into the water ring at a downward angle through the concrete shaft lining opposite the mandoor frame. At the time of the investigation, three of the four holes were found to be obstructed. The ventilation holes did not provide an effective means to ventilate the water ring. The CSE 102 methane detector was held at the drilled ventilation holes and it read "four" according to Meyer's sworn statement, as previously referenced. The methane reading was likely influenced by the shaft ventilation system and was not indicative of the actual methane concentration within the water ring; however, even this reading should have alerted Brumley that methane was present inside the water ring.
The steel forms on the inside of the shaft were removed, exposing the concrete shaft lining. A mandoor frame had been incorporated into the shaft lining to allow access into the water ring. However the panning covered the mandoor opening. The removal of the panning was essential to access and ventilate the water ring.
Initially, an opening was cut through the panning with an axe. Brumley placed a handheld methane detector just inside the opening prior to the explosion and read 0.2% methane. However, this methane reading was not indicative of actual methane concentrations within all portions of the water ring due to the placement of the detector. Brumley did not conduct tests for methane near the top of the water ring. He placed the methane detector approximately three feet from the bottom of the water ring, leaving the top four feet unexamined. Furthermore, the methane reading may have been influenced by fresh air passing through the opening and over the detector. In addition, the testing of the CSE 102 instrument revealed that it was not properly calibrated causing the instrument to indicate a lower methane concentration than was actually present.
As Abel began cutting the panning with the torch, the flame of the torch, molten metal, or the superheated surface of the panning ignited the methane-air mixture in the unventilated water ring (see Appendix U). Heated metal sparks from the cutting process would have likely extended into the water ring well beyond the reach of Brumley during the previous test for methane. An explosion developed within milliseconds, generating flame and excessive pressures.
The maximum overpressure developed during a methane explosion occurs at a concentration of about 10%. Calculations indicated that the volume of the water ring was approximately 2,300 cubic feet. The flame from a methane explosion extends about five times further than the initial methane accumulation. There was no evidence of heat impacting the ventilation tubing, located about 40 feet above the work deck; therefore, it is doubtful that a 10% mixture occurred throughout the entire water ring. Approximately 115 cubic feet of methane entering the water ring would have caused a 10% mixture throughout half the water ring. This total quantity of methane coupled with the confinement of the explosion zone would allow short-duration pressures to exceed 50 pounds per square inch (psi). Based on explosions research, the threshold pressure for a fatality is 35 psi.
The flame of the explosion encompassed the entire water ring, but was directional upon entering the shaft. Flame propagated through the mandoor frame and across the shaft. Upon impacting the opposite side of the shaft lining, the flame split and continued in both directions around the shaft lining. The estimated flame speed exceeded 2,000 feet per second. Considering the diameter of the shaft and the distance around the water ring, the explosion flame lasted approximately 50 milliseconds. Since there was no additional fuel in the shaft, the flame quickly extinguished.
Explosion force was generated by flame. Pressures significantly increased as the flame filled the confined area of the water ring, until the explosion force increased in magnitude to exceed the strength of the panning blocking the mandoor frame opening. Flame and forces shot through the mandoor frame, into and across the shaft. Evidence of the damaged panning indicated pressures exited the water ring into the shaft. As the fuel was consumed, the flame extinguished and pressures deteriorated immediately.
The flame and forces had the greatest impact on workers in direct line with the mandoor frame. Abel most likely experienced fatal injuries instantly because he was located directly in front of the mandoor frame. Mount and Roush III were on the work platform near the center of the shaft and pressures from the explosion also caused their fatal injuries. Brumley and Bair were not in the direct line of the explosion pressures and suffered serious but not fatal injuries. Meyer, who also suffered trauma and injuries, was subjected to the least flame and associated pressure because of his location away from the mandoor frame.
ROOT CAUSE ANALYSIS
A root cause analysis was conducted. Causal factors were identified that, if eliminated, would have averted the accident entirely or mitigated its severity.
Causal Factor: The examination for methane performed by the night shift foreman prior to the explosion was not adequate. An adequate examination would have required testing for methane in all areas that could have been affected by the use of the cutting torch.
Corrective Action: All certified and qualified persons who are required to conduct examinations were retrained by MSHA training specialists in the proper calibration and use of methane detection instruments and in how to properly test for methane, including the use of probes and pumps. Each certified person satisfactorily demonstrated to an MSHA inspector his ability to conduct an adequate examination.
Causal Factor: The water ring was not ventilated to dilute and remove hazardous gases. Proper ventilation of the water ring prior to performing any work would have prevented the accident.
Corrective Action: Water rings should be ventilated throughout the construction process and thereafter to prevent the accumulation of explosive gases.
Causal Factor: The water ring construction method created an unventilated area where methane was able to accumulate. This method also required the use of a cutting torch and other potential methane ignition sources.
Corrective Action: The water ring construction should incorporate a design that assures the continuous ventilation of the water ring during construction and allows access into the water ring without the use of tools that are potential methane ignition sources.
During the final stages of water ring construction, the atmosphere inside the water ring became isolated from the air shaft for approximately 26 hours. The water ring became unventilated when metal sheeting (panning) was installed to form the outside wall for a concrete pour. Methane entered the unventilated water ring during this time. The concrete curing process generated heat that caused convection currents inside the water ring to mix methane and air. This process resulted in an explosive methane-air mixture in the water ring at the time of the explosion.
Miners attempted to remove panning that blocked access to the water ring through a mandoor. The panning was partially opened with an axe after which a shift foreman performed an inadequate examination for methane and did not ventilate the water ring area. He then directed the mechanic to cut the panning with a torch. As the cutting occurred, the methane-air mixture inside the water ring ignited, resulting in a methane explosion. Contributing to the severity of the accident was the failure to limit the number of miners inside the shaft to the minimum number necessary to perform cutting and welding.
Standard CCD construction procedures for accessing water rings involved creating an opening in the panning with an axe, performing an examination for methane in the opening, and then cutting the panning with a torch if methane was not detected. Members of CCD management and some shaft miners were aware that methane could be present inside the water ring when it was unventilated and isolated from the shaft. In fact, on the night of the accident, the shaft superintendent cautioned the night shift foreman before the night shift began about the possible presence of methane in the water ring.
Based on the MSHA investigation observations and findings, the January 22, 2003, explosion that occurred at approximately 1:00 a.m. inside the 5 South #2 Airshaft, resulting in three fatal injuries and three serious, non-fatal injuries, could have been prevented. Examination for methane with a properly calibrated methane detector using a probe to evaluate the water ring area for methane would have provided a means to detect hazardous methane levels in areas where torch sparks could travel. Ventilation of the water ring area before any torch cutting was performed would have diluted and rendered harmless any accumulated explosive methane-air mixtures and prevented the explosion.
Moreover, even though conducting an adequate examination for methane and properly ventilating the water ring would have prevented the explosion, it was also practical and feasible to design and construct the water ring with mandoors and ventilation holes in a manner that would not require drilling into an unventilated area, punching through metal sheeting with an axe, nor cutting through metal panning with a torch. This construction method would eliminate the major methane ignition sources, the potential for methane explosions, and minimize the exposure of miners to these deadly hazards.
Section 103(k) Order No. 7119370 was issued on January 22, 2003 to ensure the safety of all persons at the McElroy Mine, 5 South #2 Airshaft construction site until an investigation could be completed and the area made safe. The physical investigation of the site was completed and it was determined that the area was safe for miners to return to work. The 103(k) order was terminated on March 3, 2003.
Section 104(d)(1) Citation, 77.1916(c), S&S, High Negligence
On January 22, 2003, an explosion occurred at the McElroy Mine, 5 South #2 Airshaft construction site, resulting in three fatal injuries and three non-fatal injuries. The onsite supervisor, Richard Brumley, conducted an inadequate examination for methane in the shaft immediately before directing a miner to use a cutting torch to gain access into an unventilated water ring containing an explosive methane-air mixture (5% to 15% methane). He did not test for methane near the top of the water ring where methane would most likely accumulate or in other areas within the water ring likely to be affected by the use of the cutting torch. Even though this supervisor had more than twenty years experience with methane gas and understood its characteristics, and had been warned by the supervisor from the previous shift to watch for methane, he directed a miner to operate the cutting torch to gain access to the water ring. Furthermore, this supervisor made no attempt and did not direct anyone to ventilate the water ring before directing the use of the torch to cut the panning covering the mandoor frame. Investigation interviews indicated that no one made an adequate examination for methane when accessing the unventilated water ring.
Section 104(d)(1) Order, 77.1900-1, S&S, Reckless Disregard
On January 22, 2003, an explosion occurred at the McElroy Mine, 5 South #2 Airshaft construction site, resulting in three fatal injuries and three non-fatal injuries. The operator was not in compliance with the approved Shaft Sinking Plan (Part G Ventilation Description, Item 6.). The Plan requires that the quantity and velocity of the current [of] air shall be sufficient to dilute so as to render harmless and to carry away flammable or harmful gasses. The water ring near the shaft bottom was not ventilated to keep the methane concentration at a safe level. An explosive methane-air mixture (5% to 15%) was allowed to accumulate in the water ring. The supervisor on site had more than twenty years experience with methane gas and understood its characteristics, and had been warned by the previous shift supervisor to watch for methane. In spite of his experience and this warning, he directed a miner to operate a cutting torch to gain access into the unventilated water ring containing the explosive methane-air mixture. A compressed air hose was available at the shaft bottom, but not used. Other supervisors stated that they routinely used an air hose to ventilate water rings. This failure to ventilate the water ring contributed to the explosion.
Related Fatal Alert Bulletin: