DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
DISTRICT 6
ACCIDENT INVESTIGATION REPORT
(UNDERGROUND MINE)
FATAL ELECTRICAL ACCIDENT
FOX #1 (I.D. No. 15-08977)
FOX MINING CORPORATION
SKYLINE, LETCHER COUNTY, KENTUCKY
DECEMBER 21, 1997
by
MARK V. BARTLEY
ELECTRICAL ENGINEER
STEVIE JUSTICE
COAL MINE SAFETY AND HEALTH INSPECTOR (ELECTRICAL)
Originating Office - Mine Safety and Health Administration
Coal Mine Safety and Health, District 6
100 Ratliff Creek Road, Pikeville, Kentucky 41501
Carl E. Boone, II, District Manager
ABSTRACT
On Sunday, December 21, 1997, the victim (Mr. Paul Dean Campbell) was performing electrical repair work on a 995 Volt AC (VAC) continuous mining machine receptacle. For an unknown reason the victim proceeded to unbolt the lid of a 7,200 VAC splice box located within three feet outby the section power center. The victim then apparently proceeded to work on either the ground monitor wire terminal or one of the 7,200 phase lead terminals. He came into contact with at least two of the three phase terminals, resulting in fatal injuries. The contact with the high-voltage circuit resulted in the high voltage overcurrent and ground fault relays activating and power to the mine was disconnected via the high voltage circuit breaker on the surface of the mine.
GENERAL INFORMATION
The Fox No.1 mine of Fox Mining Corporation, is located at Defeated Creek, 2.4 miles southwest of Skyline, in Letcher County, Kentucky. The principal company officer is Charles E. Yates, President. The mine is managed by Lawrence Vanover.
Fox No.1 mine began development on August 19, 1994. The mine consists of two working sections: the 007 section and the 006 section. The 007 section is developed into the Hazard No.4 coal seam which has an average mining height of 40 inches, and is located approximately 5,200 feet underground from the drift opening portals. Continuous mining machines are used on both sections to extract the coal. A continuous haulage system (mobile bridges) is used for coal haulage. Coal is then transported to the surface by conveyor belts.
Fox Mining Corporation currently employs 90 persons on two production shifts and one maintenance shift. The mine normally operates five days-per-week and processes an average of 3,000 tons per day.
The last complete health and safety inspection by the Mine Safety and Health Administration of the Fox No.1 mine (I.D. No. 15-08977) was completed on September 8, 1997.
DESCRIPTION OF THE ACCIDENT
On Saturday, December 20, 1997, at approximately 11:00 P.M., the third shift crew of the mine reported to work for a special shift. The shift was scheduled to allow the miners to take a four-day vacation over the Christmas holiday. The third shift crew of the 007 working section was under the supervision of Charles Hensley, maintenance foreman and Larry Ison, bull crew foreman. This was Charles Hensley's first night as third shift foreman. A total of seven men traveled to the 007 working section to complete a power move and perform maintenance work on the section equipment. At this mine, instructions for the maintenance personnel were normally left on work orders prepared by the previous shifts. Maintenance which could not be conducted on the production shifts was scheduled to be completed on the third shift.
Steve Bates, greaser, and Derek Cook, repairman helper, proceeded to the face area of the 007 working section to perform maintenance work on a continuous mining machine. The other members of the crew began preparing for a power move. Charles Hensley made arrangements to take the second shift roof bolter operators to the surface. Before Hensley left the section he gave orders for the power center to be moved before he returned. Ricky Miller and Rodney Wynn, general laborers arranged to get two scoops to pull the section power center into place. Wynn and Ison also disconnected cable plugs (catheads) from their receptacles, gathered chains, and removed the mats from around the power center prior to the move.
The high-voltage disconnect switch, (located on the back of the power center) was placed in the open position prior to the move. Investigators could not determine who opened the switch.
When Charles Hensley returned to the section, the power center move had not been completed. The move then began with Larry Ison at the power center. Ricky Miller and Rodney Wynn operated the two scoops that were used to reposition the power center. John Cornett, general laborer, was instructed to watch the high voltage cable while the power center was being moved. Paul Dean Campbell, repairman, and Charles Hensley, assisted in the move by placing timbers under the power center as it was being pulled through a dip in the mine floor.
The power center was moved up the belt entry approximately one crosscut. Wynn waited in the cab of one scoop while Miller traveled to the battery charging station to place his scoop on charge. Ison was located inby the power center. At some point Campbell began work on the 007 section power center to replace a female electrical receptacle for the 995 VAC continuous mining machine. Six allen bolts that secured the receptacle to the frame of the power center were removed. Hensley crawled past Paul Dean Campbell, between the power center and beltline, (traveling inby) to remove the chains from the front of the section power center. Approximately five minutes after Hensley crawled past Campbell, Hensley heard a loud boom and crawled back to the rear of the power center. Hensley observed Campbell lying across the splice box adjacent to the power center. He pulled Campbell off the splice box. The miners on the section either heard a noise or saw a flash and traveled to the accident area.
At 1:23 a.m., Derek Cook called outside via the mine phone and told Keith Oliver, outside man, that there had been an accident, and instructed him to call an ambulance.
Ricky Miller, a mine emergency technician, obtained the section first-aid kit and provided first aid treatment to Campbell.
Derek Cook stated he observed Campbell's left hand and index finger were burnt. Cook, Rick Miller, Charles Hensley and John Cornett transported Campbell to the end of track. The miners loaded Campbell onto a mantrip and Derek Cook and John Cornett rode with Campbell to the surface. At 1:33 a.m., Cook and Cornett began administering mouth-to-mouth resuscitation while enroute to the surface. Upon arrival on the surface of the mine, the victim was moved into the mine warehouse. At 1:55 a.m.,Cook checked and found a pulse. Mouth-to-mouth resuscitation continued.
At 2:00 a.m., the Letcher Fire and Rescue Ambulance Service arrived at the scene and transported the victim to the Whitesburg Appalachian Regional Hospital located at Whitesburg, Kentucky. Robert A. Campbell, Letcher County Coroner, examined the victim and pronounced Paul Dean Campbell dead at 3:30 a.m.
Company personnel informed MSHA and the Kentucky Department of Mines and Minerals (KDMM) of the accident. MSHA and KDMM personnel were dispatched to the mine to begin an investigation.
Robert Sturgill, coal mine inspector was dispatched to the mine site. He immediately issued a 103 (K) Order to ensure the safety of the miners working in the area and to secure the accident scene. MSHA management contacted District 6 electrical personnel to immediately begin an accident investigation. Upon arrival at the mine, MSHA electrical personnel traveled underground to the accident scene and evaluated the circumstances of the accident. A joint investigation by Kentucky Department of Mines and Minerals and MSHA was begun. During the investigation the high voltage system was checked from the 3,750 KVA surface substation through the 007 section load break switch to the 007 section power center. High-voltage (7,200 VAC) protective devices were checked for proper operation and settings. Results of the examination are documented in the physical factors section of this report.
PHYSICAL FACTORS
The investigation revealed the following factors relevant to the occurrence of the accident:
- The mine receives power through a 34,500 VAC service drop.
Power is transformed at that point to 7,200 volts by three
1,250 KVA transformers at an open-type surface substation
for underground transmission.
- Two overcurrent relays and one ground fault relay were
installed at the surface substation. These relays provide
the required protection to the high voltage circuit
underground (for the 006 and 007 working sections). The
Phase "A" overcurrent relay tripped due to an overcurrent
condition (settings and testing indicated the trip value to
be 240 amperes). The Phase "C" relay had tripped due to
both an instantaneous current trip condition (settings and
calculation indicate the trip value at 1,200 amperes) and an
overcurrent condition (settings and testing indicated the
trip value was 230 amperes). The ground fault relay had
tripped due to an overcurrent condition (the ground fault
relay was set to trip at 5.2 amperes). It could not be
determined when these relays had activated.
SURFACE SUBSTATION RELAY SETTINGS SUMMATION
Value Phase "A" Phase "C" Ground Overcurrent Trip
(Actual)240 amperes 230 amperes 5.2 amperes Overcurrent Trip
(Calculated)240 amperes 240 amperes 5.0 amperes Instantaneous
(Calculated)1,600 amperes 1,200 amperes 40 amperes Time Setting** 8.5 (numeric value) 6.0 (numeric value) 0.5 (numeric value)
** The numeric value for the time setting on the three relays must reference a chart to determine the time needed to trip the relay.
- Two overcurrent relays and one ground relay were also present in the 007 section loadbreak switch located approximately 1,500 feet underground. The loadbreak switch is not recognized as the legal protective device for the No.2 AWG high voltage cable to the 007 section. Section 75.800, 30 CFR, recognizes only circuit breakers for the purposes of undervoltage, grounded phase, short circuit, and overcurrent protection. The phase "A" relay in the loadbreak center was activated due to an instantaneous overcurrent condition. The phase "C" relay was activated due to an instantaneous overcurrent condition. The ground fault relay was activated due to a timed overcurrent condition.
- The high-voltage circuit that supplied 7,200 VAC three phase power to the 007 section was not deenergized, grounded, locked out, or suitably tagged before the power move and electrical work was performed. No one was instructed to lock or tag the 7,200 VAC high-voltage circuit to the 007 section before the power move.
- Monthly examinations of high-voltage electrical equipment had not been conducted since October 5, 1997.
- The operator was not maintaining a list of certified or qualified persons to perform electrical duties at this mine.
- The 7,200 VAC high-voltage loadbreak switch for the 007 working section was not operating properly. The mechanical assembly of the switch would not work when tested.
- The high-voltage load break switch supplying power to the 007 working section was not identified as the controlling switch for the circuit.
- The 1,250 KVA 007 section power center was moved while energized.
- The high-voltage 7,200 VAC visible disconnect on the section power center had been placed in the open position prior to the power move. The section power center was still energized during and after the move. The power center was moved one crosscut. The 7,200 VAC visible disconnect had not been closed immediately after the power center move stopped. Closure of the disconnect would have given an audible tone (through a humming sound) created by the energized transformers indicating to the victim that the 7,200 VAC circuit was energized.
- The allen bolts on the female receptacle that supplied 995 VAC three phase power to the continuous miner had been unbolted from the power center frame.
- A replacement female receptacle for the 995 VAC circuit was found laying beside the unbolted receptacle.
- Allen wrenches were found in the victim's possessions following the accident.
- The cover for the 7,200 VAC splice box was found laying at an angle on the side of the splice box.
- The high-voltage failsafe ground monitor circuit contained a short circuit on the outby side of the high-voltage splice box where the victim was working. This condition prevented the sectionalizer loadbreak switch from tripping when the cover on the splice box was removed. The splice box had two high voltage ground monitor cover switches installed, one of which was found to be locked in the closed contact position. The other cover switch was operative.
- A 9/16" combination wrench (open-end/boxed-end) was found inside the splice box. Five bolts within the splice box were 9/16" in size. The three phase-lead termination bolts were 9/16" and the two termination point bolts for the high voltage monitor wire were 9/16".
- Electrical arc marks were found on all three 7,200 VAC phase conductor stand-off insulators located within the splice box. Apparently, the victim believed there was a ground monitor problem or a loose connection on one of the three 7,200 VAC phase conductor stand-off insulators.
- Miners who were near the section power center at the time of the accident stated they heard a loud pop and/or saw flashes.
- The victim was found lying face down on top of the splice box.
- Evidence indicates that the victim made contact with at least two phases of the 7,200 VAC circuit inside the splice box and that this contact initiated an arc which resulted in burn injuries to the victims left arm.
- Testimony of coworkers and management personnel indicated that no one had any knowledge as the reason(s) for the victim performing work inside the splice box. The lug nuts on the phase terminals and the ground monitor terminal inside the splice box were 9/16-inch in size. A 9/16-inch combination wrench was found inside the splice box. The investigation team's consensus is that the victim apparently intended to work on either the ground monitor wire terminal or one of the 7,200-volt phase terminals.
- The victim was not a certified electrician.
- There was no certified electrician (as defined by 30 CFR, Part 75.153) on the 007 working section at the time of the accident.
- A volt/ohm meter was not found near the accident scene.
- The certificate of death lists the immediate cause of death as electrocution.
- Two overcurrent relays and one ground relay were also present in the 007 section loadbreak switch located approximately 1,500 feet underground. The loadbreak switch is not recognized as the legal protective device for the No.2 AWG high voltage cable to the 007 section. Section 75.800, 30 CFR, recognizes only circuit breakers for the purposes of undervoltage, grounded phase, short circuit, and overcurrent protection. The phase "A" relay in the loadbreak center was activated due to an instantaneous overcurrent condition. The phase "C" relay was activated due to an instantaneous overcurrent condition. The ground fault relay was activated due to a timed overcurrent condition.
CONCLUSION
The victim was performing electrical work in a 7,200 VAC splice box on the 007 working section when he contacted at least two phases of the high-voltage system. The circuit had not been deenergized, grounded, locked out, or suitably tagged prior to electrical work being performed.
VIOLATIONS
- A 103(k) Order (No. 4021395) was issued on December 21,
1997, to Fox Mining Corporation of Kentucky. The order was
issued to ensure the safety of the miners working in the
area and to ensure that the area was not disturbed so that
an investigation could be conducted.
- A 104(d)(1) Citation (No. 4496093) was issued on December
24, 1997, to Fox Mining Corporation of Kentucky, for
violating 30 CFR, Part 75.511. The citation was issued for
failure to lock out and suitably tag the electrical system
before electrical work was performed on the 7,200 VAC
electrical system. Management ordered and authorized a
power move while the power center was energized.
- A 104(d)(1) Order (No. 4496094) was issued on December 24,
1997, to Fox Mining Corporation of Kentucky, for violating
30 CFR, Part 75.812. The order was issued for the movement
of a 1250 KVA, 7,200 VAC high-voltage power center while
energized. The high-voltage power center was located on the
007 working section.
- A 104(d)(1) Order (No. 4490461) was issued on December 24,
1997, to Fox Mining Corporation of Kentucky, for violating
30 CFR, Part 75.511-1. The order was issued for a
nonqualified person performing electrical work. The victim
was not qualified according to 30 CFR, Part 75.153, and was
performing electrical work at the time of the accident.
- A 104(d)(1) Order (No. 4490462) was issued on December 24,
1997, to Fox Mining Corporation, for violating 30 CFR, Part
75.509. The order was issued for failure to deenergize all
power circuits and equipment on the 007 working section
before electrical work was performed.
- A 104(a) Citation (No. 4490464) was issued on December 24,
1997, to Fox Mining Corporation of Kentucky, for violating
30 CFR, Part 75.800-3. The citation was issued for failure
of the company to make monthly examinations of the high-voltage
circuit breakers and their auxiliary devices
protecting underground high-voltage circuits.
- A 104(a) Citation (No. 4496092) was issued on December 24,
1997, to Fox Mining Corporation, for violating 30 CFR, Part
75.512. The citation was issued for failure of the company
to properly maintain the 7,200 VAC high-voltage loadbreak
switch in a safe operating condition.
- A 104(a) Citation (No. 4490463) was issued on December 24, 1997, to Fox Mining Corporation of Kentucky, for violating 30 CFR, Part 75.803. The citation was issued for failure of the company to maintain a failsafe ground check monitor system for the 7,200 VAC high-voltage circuit provided for the 007 working section power center (1,250 KVA).
Respectfully submitted :
Mark V. Bartley
Electrical Engineer/Accident Investigator
Stevie Justice
Electrical Coal Mine Inspector/Accident Investigator
Approved By:
Carl E. Boone, II
District Manager
Related Fatal Alert Bulletin:
FAB97C29