Skip to content
UNITED STATES
DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION

District 6

ACCIDENT INVESTIGATION REPORT
Underground Coal Mine

FATAL ELECTRICAL ACCIDENT


NO. 1 MINE - I.D. NO. 15-16162
BEECH FORK PROCESSING, INC.
VAN LEAR, JOHNSON COUNTY, KENTUCKY
SEPTEMBER 12, 1995

BY

GAREY L. FARMER
Coal Mine Safety and Health Inspector/Accident Investigator

ROBERT M. BATES
Electrical Engineer

MARK BARTLEY
Electrical Engineer


Originating Office - Mine Safety and Health Administration
100 Ratliff Creek Road, Pikeville, Kentucky 41501
Carl E. Boone II, District Manager

GENERAL INFORMATION

The No. 1 Mine of Beech Fork Processing, Inc., is located off Kentucky Route 3, on Lackey Branch near Van Lear, Kentucky. The principal company officers are: James H. Booth, president; Ted McGinnis, secretary/treasurer; Leslie Combs, mine superintendent; Mike Marcum, mine foreman; and Link Chapman, safety director.

Coal is extracted from the Coalburg seam utilizing continuous miners and shuttle cars. The coal seam averages 86" in height. Coal is transported to the surface via belt conveyor. The mine currently employs forty-nine persons on two production shifts and one maintenance shift per day. The mine normally operates five days per week and produces an average of 2500 tons per day from two active sections.

The last health and safety inspection by the Mine Safety and Health Administration was completed on September 7, 1995.


DESCRIPTION OF ACCIDENT

On Tuesday, September 12, 1995, the evening shift crew was mining coal on the 002 working section under the supervision of Jerry Hall, section foreman. Activities were normal until approximately 11:45 P.M.

Preceding the accident, Rex Hall, No.3 shuttle car operator, was having electrical problems with the machine he was operating. At this time, the No.3 shuttle car trailing cable was plugged into the power center receptacle labeled "NO.3 SC". J.D. Spears, No.2 shuttle car operator, was also experiencing electrical problems with the machine he was operating. The No.2 shuttle car trailing cable was plugged into the receptacle labeled "SPARE". The receptacle labeled "NO.2 SC" was out of service at the time. When the circuit breaker for the No.3 shuttle car tripped, J.D. Spears proceeded to the 002 section power center at the request of Rex Hall to reset the breaker.

Jerry Newsome, 002 section electrician, heard a circuit breaker trip and proceeded to the section power center to investigate. Newsome met Spears at the power center and attempted to reset the No.3 shuttle car circuit breaker. The circuit breaker would not reset. Newsome instructed Spears to tell Rex Hall to park the No. 3 shuttle car until the problem with the circuit could be determined. According to Newsome, he then switched the cable couplers, plugging the No.3 shuttle car coupler into the "SPARE" receptacle and the No.2 shuttle car coupler into the "NO.3 SC" receptacle. This was evidently done in an attempt to engage the two circuits and isolate the malfunction.

At some point during this rearrangement of cable couplers, the No. 2 shuttle car circuit (with a phase-to-ground fault) and the No. 3 shuttle car circuit (with a phase-to-ground fault) were energized simultaneously. During this simultaneous activation of circuits the victim contacted the frame of the No. 3 shuttle car and ground. Contact with the frame of the No. 3 shuttle car and earth resulted in the victim's exposure to a double phase-to- ground fault. Within minutes of the accident the victim was discovered and immediately transported to the surface of the mine.


PHYSICAL FACTORS

The investigation revealed the following factors relevant to the occurrence of the accident:

  1. There were no eyewitnesses to the accident.

  2. The 002 section was located approximately 8400 feet from the mine portal.

  3. The 002 section was generally wet and muddy.

  4. The mine receives power from Big Sandy Rural Electric Cooperative Corporation through a 13200 VAC service drop. Power is transformed at that point to 7200 VAC by a 3000 KVA totally enclosed substation for underground transmission.

  5. Three Joy 10SC shuttle cars were being utilized on the 002 section.

  6. Trailing cables (#2 AWG), approximately 650 feet in length, were utilized for the three 10 SC shuttle cars on the 002 section.

  7. The operating voltage for the 10 SC shuttle cars on the 002 section was 480 VAC. The operating voltage for the continuous miner was 575 VAC.

  8. A phase-to-ground fault was present in a splice in the No. 2 shuttle car trailing cable. The fault was located approximately 280 feet from the cable connection point on the shuttle car. One of the phase conductors was in contact with the ground wire for a distance of approximately six inches.

  9. A phase-to-ground fault was also present on the shuttle car operated by the victim (No.3 shuttle car) at the time of the accident. This fault occurred when an exposed phase conductor came to rest on the metal cable guide. The exposed area was approximately two inches in length.

  10. The two ground fault conditions were on different phases of the 480 VAC system.

  11. The resistance of the ground wire and faulted phase conductor (to the point of the fault) was measured for each of the trailing cables involved in the accident. The following values were obtained:

    #2 SC ground wire - 0.3 ohms;
    #2 SC faulted phase conductor - 0.3 ohms;
    #3 SC ground wire - 0.8 ohms;
    #3 SC faulted phase conductor - 0.3 ohms.

    Using the above values of resistance and neglecting cable reactance, the approximate voltage to which the victim was exposed was 225 VAC. According to calculations, the phase- to-phase current flow during the fault was not sufficient to activate the instantaneous trip unit on the affected circuit breakers.

  12. The 22-ohm grounding resistor for the 002 section power center was found to be intact at the time of the investigation. The ground wires for the No.2 and No.3 shuttle car trailing cables were also intact.

  13. The cable couplers were unplugged prior to the MSHA investigation team's arrival at the accident scene. This prevented an absolute determination of the location of the cable couplers with respect to the receptacles on the power center at the time of the accident.

  14. The circuit breakers protecting the shuttle car circuits on the 002 section had the following characteristics:

    LABEL CIRCUIT RATING INST. UNIT APPROX. SETTING
    No. 1 SC#7225 A300-700700
    No. 2 SC#6225 A300-700700
    No. 3 SC#5225 A500-1000800
    SPARE#8225 A300-700700

  15. Two of the four circuit breakers used to protect trailing cables for shuttle cars on the 002 section were found to be inoperative. The circuit breaker identified as "NO. 2 SC" had the undervoltage release power wires disconnected. The circuit breaker identified as "NO. 3 SC" would not engage due to an inoperative undervoltage release mechanism.

  16. Testimony indicated that the two circuit breakers in use at the time of the accident were labeled "NO.3 SC" and "SPARE".

  17. The ground monitor / ground fault units utilized for the shuttle car circuit breakers were manufactured by Pemco. [Part nos. 21059 and 21077, MSHA Approval no. 092876 P(2)]

  18. The ground monitor / ground fault units for the "SPARE", "NO.1SC", and "NO.2SC" circuit breakers were sent to MSHA's Approval and Certification Center (A&CC) for testing. A ground fault reset switch, which had been removed from the "SPARE" unit after the investigation, was also sent to A&CC. The ground monitor / ground fault unit for the "NO.3SC" circuit breaker could not be obtained for testing.

  19. The results of the tests, which are contained in A&CC Investigative Report No. LI95-06, are summarized as follows:

    1. The "SPARE" unit was labeled as Pemco part no. 21077, but was actually wired in accordance with part no. 21054. These units (part no. 21054) will not respond to a ground fault if the ground fault reset switch is held in the depressed (contacts open) position.

    2. The ground fault reset switch removed from the "SPARE" unit was not operational when tested. However, the contacts of the switch were stuck in the closed position, which would not have defeated the ground fault protection.

    3. The "NO.1SC" and "NO.2SC" units were labeled as Pemco part no. 21059 and were wired accordingly. Holding the ground fault reset switch in the depressed position on these units does not disable the ground fault protection.

    4. The ground fault circuit and ground monitor circuit on all three units functioned properly when tested.

  20. The high voltage substation and ground monitor circuits were tested and found to be in compliance with 30 CFR.

  21. The victim was found lying face down with his left elbow against the hub of the right rear wheel of the No. 3 shuttle car.

  22. An autopsy indicated that electrocution was the cause of death.


CONCLUSION

The No. 3 shuttle car operator was fatally injured when he contacted the energized frame of the No. 3 shuttle car and earth.

A phase-to-ground fault was present in the section electrical system in the No. 2 shuttle car trailing cable. A phase-to- ground fault was also present on the No. 3 shuttle car where a bare phase conductor was in contact with the frame. Due to the phase-to-ground faults in different phases of the electrical system, the victim's contact with No. 3 shuttle car and earth resulted in his exposure to approximately 225 VAC and elevated current flow.


VIOLATIONS

  1. A 103(k) Order (No. 4517963) was issued on September 13, 1995, in conjunction with this investigation.

  2. A 104(a) Citation (No. 4014781) was issued on September 15, 1995. A splice in the No.2 Joy shuttle car cable was not effectively insulated. The citation was issued under Title 30 CFR, Part 75.604.

  3. A 104(a) Citation (No. 4506688) was issued on September 15, 1995. The No. 3 Joy shuttle car cable was not adequately insulated. The citation was issued under Title 30 CFR, Part 75.517.

  4. A 104(a) Citation (No. 4506689) was issued on September 15, 1995. The No. 3 Joy shuttle car was not provided with grounded phase protection. The citation was issued under Title 30 CFR, Part 75.900.

  5. A 104(a) Citation (No. 4506690) was issued on September 15, 1995. The No. 2 Joy shuttle car was not provided with grounded phase protection.The citation was issued under Title 30 CFR, Part 75.900.

  6. A 104(a) Citation (No. 4588271) was issued on September 21, 1995. The scene of the accident was altered before an investigation could be conducted by MSHA. The citation was issued under Title 30 CFR, Part 50.12.

  7. A 104(a) Citation (No. 4506700) was issued on September 21, 1995. The operator was not conducting adequate electrical examinations. The citation was issued under Title 30 CFR, Part 75.512.



Respectfully submitted by:

Garey L. Farmer
Coal Mine Safety and Health Inspector/Accident Investigator

Robert M. Bates
Electrical Engineer

Mark V. Bartley
Electrical Engineer


Approved by:

Carl E. Boone, II
District Manager

Related Fatal Alert Bulletin:
Fatal Alert Bulletin Icon FAB95C31