DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
District 3
ACCIDENT INVESTIGATION REPORT
(Underground Coal Mine)
FATAL ELECTRICAL ACCIDENT
Meigs #2 Mine (I.D. No. 33-01173)
Southern Ohio Coal Company
Albany, Meigs County, Ohio
July 23, 1998
by
Franklin Homko
Coal Mine Safety and Health Inspector
Ronald L. Wyatt
Mining Engineer, Roof Control
and
Ronald L. Sidwell
Coal Mine Safety and Health Inspector (Electrical)
Originating Office - Mine Safety and Health Administration
Coal Mine Safety and Health, District 3
5012 Mountaineer Mall, Morgantown, West Virginia 26501
Timothy J. Thompson, District Manager
GENERAL INFORMATION
The Meigs #2 Mine is a large underground coal mine operated by the Southern Ohio Coal Company. The mine is located off State Route 689, seven miles southeast of Albany, Ohio. The mine is opened by five shafts and a two compartment slope into the Clarion 4A coal seam which averages 54 inches in thickness. Employment is provided for 313 persons of which 279 work underground on three production shifts per day, six days a week. The mine produces an average of 18,643 tons of coal daily from three continuous-mining sections and one longwall mining section. Coal is transported from the face by shuttle cars and discharged onto belt conveyors. The coal is then transported by the belt conveyors to two coal storage bins located underground. Coal from the storage bins is discharged by coal feeder units onto a 42-inch collecting belt conveyor. The collecting belt discharges onto a 54-inch wide slope conveyor belt that transports the coal to the surface for processing. A track-trolley haulage system is used to transport supplies, materials, and employees into and out of the mine. The mine purchases three-phase power at 138 kV and distributes it to surface substations at 34.5 kV. Four high-voltage substations are used to distribute three-phase power at 7620 vac to underground power centers and rectifiers. The power centers provide utilization voltages of 1 kV, 575 vac, 480 vac, and 110/220 vac. The rectifiers supply 300 vdc for transportation equipment on the trolley/track system, pumps, and bonders. The 3000 kVA Hoist House Substation, connected Delta-Wye, supplies three-phase 4160 vac power to the hoist house where it is distributed to several locations on the surface at voltages of 4160 vac, 600 vac and 110/220 vac and to the underground slope area at voltages of 110/220 vac and 110/208 vac. Mine ventilation is accomplished by four main mine fans located on the surface exhausting approximately 1,234,874 cubic feet per minute of air. The mine liberates 436,229 cubic feet of methane every 24 hours.
The principal mine officials are as follows:
Lance G. Sogan | Vice President and General Manager | |
Ray C. Lieving | Superintendent | |
Tim A. Martin | Safety Director |
The last safety and health inspection was completed on July 13, 1998.
DESCRIPTION OF ACCIDENT
On Thursday, July 23, 1998, work at the Meigs #2 Mine included the tasks of removing, repairing and replacing component parts of the collection belt located underground near the end of the slope belt conveyor. To accomplish this, a belt conveyor repair crew and a belt maintenance crew were assigned to work in this area.
The 7:00 a.m. to 3:00 p.m. shift belt conveyor repair crew consisted of Ernie Compson, Danny J. Hood, Willam R. Willams, Greg Peck, Jim Williams, Osler Sayre, and Bruce Brunton, supervised by David L. Shinn, Belt Foreman. At the beginning of the shift, the crew was assigned to remove, repair and replace component parts of the collecting belt conveyor. A safety and job procedure meeting was conducted with the crew by Donald W. Goodson, General Maintenance Supervisor, and John T. Moore, Belt Coordinator. During the meeting, crew members were advised that they could receive an electrical shock from time to time when using the electrical arc welder or bonder units in the wet areas. Leather welding gloves and electrically rated rubber gloves with leather protectors were distributed to the crew members. The crew then traveled underground to the work site, arriving about 7:30 to 8:00 a.m. Work preparation of setting up tools and equipment to remove, repair and replace the component parts of the belt conveyor was started.
The 8:00 to 4:00 p.m. belt maintenance crew consisted of Jerry Collins, Gary Northrup, Glen Arrowwood, Henry Van Meter, Steve Ehman, and Robert S. Shain, supervised by Ronald E. Black, Maintenance Supervisor (Victim). At the beginning of the shift the crew was assigned to replace electrical equipment and repair equipment associated with the No. 1 coal bin feeder unit located at the site of the collecting belt conveyor. Some crew members were to assist the belt repair crew in the task of removing, repairing, and replacing components of the collecting belt conveyor. A safety and job procedure instructional meeting was conducted with the crew by Ronald E. Black, Maintenance Supervisor. Crew members were made aware of the possibility of receiving electrical shock when working in the area of the collecting belt conveyor when using the bonder or welder. Leather welding gloves and electrically rated rubber gloves with leather protectors were distributed to the crew members. The crew then traveled underground to the worksite, with some members arriving sometime after 8:00 a.m., and others not arriving until about 10:00 a.m.
The No. 1 coal storage bin and feeder were cleaned of any residual loose coal and coal dust by using a wash down hose. This was done from the top portion of the bin where the Main North belt conveyor discharged coal into the bin during normal production shifts. Donald W. Goodson arrived at the top portion of the bin area about 10:00 a.m. to monitor the crew's work activities and to assist them with any problems they might encounter.
About 10:30 a.m., David L. Shinn, Belt Foreman, telephoned Curtis C. Casto, Outside Hoist Operator, to have him deenergize all electrical equipment and circuits associated with the operation of the collecting belt conveyor. Casto told Shinn the belt power had to be deenergized at the underground control panel station. Casto also informed Shinn that he could not deenergize the belt control switch circuit and operate the slope belt at a reduced speed to transport the dismantled component parts of the collecting belt conveyor to the surface. Power to the collecting belt conveyor was deenergized, locked and tagged out, but power remained on the two belt control switches. Crew members began dismantling component parts of the collecting belt conveyor. These parts were then placed on the slope belt and transported to the surface. The belt repair crew used a 300 vdc electric bonder, having an open-circuit voltage of 300 vdc, in conjunction with an air-arc attachment to cut away the structure from the belt conveyor. The maintenance crew used a 575 vac welder, having an open-circuit voltage of 32 vac, in conjunction with and air-arc attachment to cut material from the No. 1 bin located just above the inby end of the collecting conveyor belt.
Danny J. Hood, Belt Repairman, stated that Greg Peck, Belt Repairman, received an electrical shock between 10:30 a.m. and 11:00 a.m., when handling dismantled metal belt structure. The air-arc stinger was laying on the rubber conveyor belt in the work area with the cutting rod in contact with the wet belting and/or metal structure. The air-arc attachment was repositioned to alleviate the shock hazard. Hood, with the assistance of Ernie Compson, began cutting the side connecting structure away from the tailpiece end of the connecting belt about 11:15 a.m.
About 12:30 p.m., the tailpiece portion of the collecting belt conveyor had been isolated from the main portion by removing all metal structure for a distance of 11 feet 6 inches in length. This left only the 42-inch wide rubber conveyor belt between the existing belt structure and tailpiece structure which had 110/220 vac belt control pullcord switches attached to its frame along with two "Hawkeye" belt speed sensors.
Crew members, who were either carrying removed metal structure, or cutting it away from the isolated tailpiece structure, began reporting they were receiving noticeable electric shocks. Black and Shinn, Foremen, who were aware of the persons receiving electrical shocks from about 12:30 p.m. to 12:45 p.m., began to try and locate the source of the shocks. The power cable from the 300 vdc bonder to the air-arc attachment was examined, found to contain defects in the cable, and was removed from service. The 300 vdc bonder was also deenergized. A new bonder cable was installed for the air-arc attachment, but the 300 vdc bonder was never reenergized because personnel were still receiving electric shocks.
About 1:15 p.m., Shinn notified Goodson of the shock hazard and asked Goodson to check the ground connection for the air-arc welding unit at the top of the No. 1 bin location. Shinn discussed the shock hazard with Black and Goodson. Goodson told Shinn to examine the ground connection for the 575 vac arc welder at the worksite. This was done and found to be adequate. Power to the lights present in the entry was removed but crew members still continued to be shocked. At no time during the process of eliminating power sources was test equipment used to determine the source of the electrical shock hazard. Black and Shinn discussed the continuing occurrence of persons receiving electrical shocks and decided that the tailpiece structure was the source. This was also the consensus of the crew members. Black had been shocked twice at two different times reportedly between about 1:30 p.m. and just prior to the fatal accident.
Shinn contacted Goodson by telephone and told him to deenergize all power to electric equipment which was present in the area of the collecting belt conveyor. This was done at the location underground where the power distribution points originated at the top of the No. 1 bin area. However, the shock condition still existed. Black then told Shinn to have personnel in the outside hoist house deenergize all electrical circuits providing power for equipment in the affected area. The circuit breakers for the belt control switches and associated circuitry, along with power to the slope belt conveyor, had not been deenergized prior to working in this area. Shinn traveled to the location of the telephone and was about to call outside to have all electrical circuits deenergized when he was notified that Black was injured and laying on the floor at the tailpiece area. Ronald Black had been walking in a wet concrete drainage ditch alongside the tailpiece belt structure when his left arm contacted the metal structure.
Danny Hood, an eyewitness to the accident, was standing about eight feet from Black. He immediately traveled to a location behind Black to attempt to lift him from the floor. Shinn, who now was also present, assisted Hood but neither man could lift the victim from the mine floor. Robert S. Shain, Mechanic, was nearby and immediately traveled to the accident scene to assist. Shain attempted to lift Black by his belt equipment harness but the harness became entangled in a metal belt tailpiece guard which was leaning against the concrete wall of the entry. Shain lowered Black to the floor and repositioned his hands and arms under Black's armpits to again attempt to lift him. Shain then received a severe electrical shock which knocked him backwards and onto the floor. Shain continued to receive electrical shocks while sitting on the wet floor and on two wire rope slings.
Gary Northrup and Glenn Arrowwood, Mechanics, who had now arrived at the accident site, picked Shain up from the floor and also received electrical shocks. They managed to get Shain on his feet and the electrical shocks ceased. In the meantime, Ernie Compson, Belt Repairman, called outside to Curtis C. Casto, Hoist Operator, and told him to turn off all power entering the slope and connecting belt conveyor entry, including the circuits for the belt pullcord switches. Casto, assisted by Ronnie Collins, Electrician, who was now present at the hoist house, deenergized the circuits.
At the accident site, Shinn checked Black for vital signs, found none, and began administering CPR. Further assistance had been summoned. Nearby miners and crew members arrived at the scene, assisted in the administration of CPR, and the transportation of Black and Shain to the surface.
Emergency squad units from Pomeroy, and Rutland, Ohio, and MedFlight life flight services from Columbus and Wellston, Ohio, had been summoned and were present on the surface of the mine. Robert Shain was transported to the Ohio State Hospital in Columbus, Ohio, by the life flight unit, treated and admitted. Ronald Black was life flighted to the Oblinus Hospital in Athens, Ohio, where he was pronounced dead.
At 3:00 p.m., Robert Klatt, Human Resources Manager, notified Charles Jones, Coal Mine Safety and Health Inspector, of the Wellston, Ohio Field Office, of the accident. Upon arrival of MSHA personnel at the mine site, a 103(k) Order was issued to ensure the health and safety of the miners.
PHYSICAL FACTORS INVOLVED
- David L. Shinn, Belt Foreman, conducted a preshift
examination of the slope belt entry and connecting belt entry
from about 7:15 a.m., to 7:55 a.m., with no hazardous conditions
disclosed.
- About 10:30 a.m., David L. Shinn, Belt Foreman, telephoned
Curtis C. Casto, Outside Hoist Operator, to have him deenergize
all electrical equipment and circuits associated with the
operation of the collecting belt conveyor. Shinn was told the
belt power had to be deenergized at the underground control panel
station. Casto informed Shinn that he could not deenergize the
circuit provided for the belt control switches and continue to
operate the slope belt. The slope belt was to be operated at a
reduced speed to transport the dismantled component parts of the
collecting belt conveyor to the surface.
- Power to the collecting belt conveyor drive motor was
deenergized, locked and tagged out by Jerry Collins, Mechanic,
to prevent accidental movement of the belt flight while repair
work was being performed.
- The 300 vdc electric bonder and 575 vac arc welder had been
modified to be used as a cutting tool instead of a welding tool.
The tool was called a slicer or air-arc. A special electrode
holder and rod, along with air injected through the holder and
the hollow rod, created a cutting action when applied to metal
objects. The air was supplied by compressed gas cylinders.
- About 12:30 p.m., the tailpiece portion of the collecting
belt conveyor was isolated from the major portion of the belt
flight with the rubber belting still in place. This was done by
removing all metal parts and structure from the belt flight for a
distance of 11 feet 6 inches. The tailpiece portion of the belt
flight was 13 feet 9 inches in length and consisted of belt
structure, a tailpiece roller, two "Hawkeye" belt speed sensors,
and an upright metal channel frame to which two pullcord belt
control switches were attached. The "Hawkeye" belt speed sensors
provided a pulsating signal to monitor movement of the tailpiece
roller for belt slippage. The two belt control switches were
powered by a 110/220 vac circuit and were provided to stop
movement of the collecting belt conveyor when necessary.
- Ronald Black, victim, contacted the metal structure of the
collecting belt conveyor at a point where the "Hawkeye" belt
speed sensors were mounted on a metal bracket installed for that
purpose at the tail roller.
- The concrete mine floor was wet with standing pools of water
present in the drainage ditch (18 inches wide by 7-12 inches deep) in the walkway which was 50 inches wide. The clearance of the walkway was reduced to approximately 18 inches by two pieces of belt guarding that had
been stored along the concrete rib. The victim had been standing
in the ditch. Black's leather boots and clothing were wet and he
was not wearing gloves.
- Ronald Black and various crew members received electrical
shocks from about 12:30 p.m., until about 2:00 p.m., the time of
the accident. Personnel assumed the 300 vdc electric bonder or
575 vac arc welder was the source of the shocks. The bonder, arc
welder, and associated equipment were examined with a defect
observed and corrected in the bonder power cable. Lights
provided in the entry were deenergized in an attempt to determine
the source of the shocks. Persons were told to deenergize power
to any electrical equipment which was in the affected area, such
as water pumps, coal feeder units, and a hydraulic operated power
pack unit. Finally, Black told Shinn to have all power circuits,
including the belt control switch circuits, deenergized. These
circuits originated in the hoist house on the surface. Before
this was accomplished, Black was electrocuted. After the belt
switch circuit was deenergized, no crew members received
electrical shocks. Test equipment was never used to determine
the source of the power creating the electrical shocks.
- David Shinn, Belt Foreman, stated he was made aware of
persons receiving electrical shocks about 12:45 p.m. Donald W.
Goodson, General Maintenance Supervisor, was informed of the
condition about 1:15 p.m. by Shinn. They did not consider this
condition to be a hazard. They assumed the bonder or welder was
the source and, even after eliminating such equipment, the
condition was still not considered a hazard. Thus, the affected
area was not posted with a danger sign and persons were not
removed from the area. Persons remained in the area either
performing regular job-related activities or work related to
finding the source of the shock hazard.
- There were bare uninsulated energized power wires, one No.
10 AWG and one No. 12 AWG, which contacted the metal enclosure of
the belt pullcord switch located along the right side of the
collecting belt. This condition created a grounded phase of the
220 vac control circuit which elevated the metal frame of the
enclosure and the associated metal belt structure to a maximum
value of 110 vac.
- An approved method of grounding was not provided for the
metal enclosures that housed the 110/220 vac control circuit
originating in the hoist house located on the surface. Several
enclosures, located from the hoist house to the underground area,
were examined and the metal frames were not connected to a
separate grounding conductor to establish a continuous connection
to the grounded center tap of the source transformer. This
included the two belt control switches located at the tailpiece
structure. The rigid metal conduit, originally used as the
grounding conductor for this circuit, contained sections that
were broken or that had been replaced with rigid nonmetallic
conduit or liquid tight flexible metal conduit. Prior to the
accident, crew members stated they had observed power wires
present in a broken conduit of the belt control switch.
- When a ground fault condition occurred in the 110/220 vac
circuit providing power to the pullcord switch located along the
collecting conveyor belt, the 15 ampere circuit breaker providing
short circuit and over current protection for this circuit failed
to open.
- The pullcord switch, located on the right side of the tail
section of the collection belt, was not provided with adequately
insulated bushings. When examined, the two openings of the
switch, used to allow power wires to enter, contained damaged and
deteriorated bushings. This allowed the wires to contact the
metal enclosure. Two of the power wires were uninsulated.
- The following conditions were not reported by the person
conducting an examination of electrical equipment in the
collection belt area on July 21, 1998:
- The conduit, containing conductors providing 220 vac
power to two pullcord switches, was broken in four locations.
- There were three broken conduits containing conductors which
provided power to belt and feeder motors.
- Each of the conduits, which contained conductors entering a
junction box, located adjacent to the collection belt, were
broken where they entered the box.
- There were damaged and deteriorated insulated bushings on
each of the two pullcord switches located at the tail of the
collection belt.
- There were two bare exposed energized conductors present in the broken conduit at the pullcord enclosures.
- The conduit, containing conductors providing 220 vac
power to two pullcord switches, was broken in four locations.
- Electrical examinations were not being conducted on a weekly
basis.
- A 25 kVA, 4160/220/110 vac single phase transformer, located
in the hoist house motor control center, was used to supply power
and control circuits at 110/220 vac. The center tap of the
transformer was solidly connected to the system grounding medium
within the motor control center. A distribution panel located
beside the motor control center was used to protect the power and
control circuits. The control circuit involved in the accident,
identified as wires M25 and M26, was protected by a 15 ampere
circuit breaker at the distribution panel and was identified as
Circuit No. 3. The control circuit entered several metal
electrical enclosures along the slope belt and collection belt
conveyor, including the two pullcord switches. A grounding
conductor was not provided that would establish a continuous
connection to a grounded center tap of the source transformer as
a frame ground from any of these metal enclosures. The two
conductors of the 220 vac control circuit, which provided power
to the pullcord switch enclosure on the right side of the
tailpiece section, were shorted and fused together at the
entrance hole at the top of the enclosure. The investigation
also revealed that the two conductors had also burned into the
metal enclosure, creating a phase-to-ground fault. This condition
energized the metal frame of the belt control switch and
associated belt structure.
- Tests were conducted and observations made on the 575 vac welder, 300 vdc bonder, 575 vac dewatering pumps, 110 vac extension cords, 110 vac lighting circuits and Hawkeye belt speed sensor circuits. These tests and observations revealed no evidence that any conditions were present in any of these circuits or equipment that may have contributed to the electrical injury or the fatality.
CONCLUSION
The accident and resultant fatality occurred because the victim came in contact with the energized portion of the metal belt structure near the tailpiece roller.
Contributing factors to the accident were as follows:
- The belt structure became energized due to a phase-to-ground
fault condition in the 110/220 vac circuit present in a belt
control switch which was attached to the belt structure.
- An approved method of grounding metallic frames of enclosures
was not provided for the belt control switches.
- A phase-to-ground fault condition occurred and the circuit's
15 ampere circuit breaker did not open.
- The concreted mine floor was wet with standing water in a
drainage ditch in the walkway.
- The victim was wearing wet leather boots, wet clothing, and no gloves.
ENFORCEMENT ACTIONS
The following violations were determined to have caused or
contributed to the accident:
- A violation of 30 CFR 75.515, 104(a) Citation No. 7126576,
was issued for insulated wires (two) passing through the two
holes in the metal frame of the belt control switch not being
provided with insulated bushings at these entrances.
- A violation of 30 CFR 75.517, 104(a) Citation No. 7126579,
was issued for power wires not being insulated adequately and
fully protected. There were bare, exposed portions of the wires
present at the belt switch entrance hole of the metal frame.
- A violation of 30 CFR 75.518, 104(a) Citation No. 7126580,
was issued for automatic circuit breaking devices or fuses of the
correct type and capacity not installed so as to protect electric
equipment and circuits, such as the belt switches and the
provided 110/220 vac circuitry.
- A violation of 30 CFR 75.363(a), 104(d)(1) Citation No.
7126577, was issued for the hazardous condition of persons
receiving electrical shocks and the affected area not posted with
a danger sign and persons prevented from entering the area.
- A violation of 30 CFR 75.701-2, 104(d)(1) Order No. 7126578,
was issued for failure to provide an approved method of grounding
for the single phase 110/220 vac control circuit supplying power
to electrical equipment with metal enclosures, including belt
control switches.
A violation of 30 CFR 75.512, 104(d)(1) Order No. 7126581, was issued for electric equipment associated with the collecting belt conveyor not being frequently examined, tested and properly maintained to assure safe operating conditions.
- A 103(k) Order No. 3499972 was issued to ensure the health and safety of the miners until the investigation could be completed.
Submitted by:
Franklin Homko
Coal Mine Safety and Health Inspector
Ronald L. Wyatt
Mining Engineer, Roof Control
Ronald L. Sidwell
Coal Mine Safety and Health Inspector, (Electrical)
Approved by:
Timothy J. Thompson
District Manager
Related Fatal Alert Bulletin:
FAB98C17