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

District 6

ACCIDENT INVESTIGATION REPORT
SURFACE COAL MINE
FATAL ELECTRICAL

Cedar Creek No. 5 Surface [I.D. No. 15-15648]
Clark Elkhorn Coal Company
Elkhorn City, Pike County, Kentucky

MAY 11, 1995

By

Buster Stewart
Coal Mine Safety and Health Specialist

Mark V. Bartley
Electrical Engineer

Robert Bates
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 Cedar Creek No. 5 Surface mine of Clark Elkhorn Coal Company is located off US Route 460, approximately two miles Southeast of Belcher, Pike County, Kentucky. The principal company officers are: Randy May, president; Roger Cantrell, safety director; and David Childers, mine superintendent. Clark Elkhorn Coal Company is a subsidiary of SMC Mining Company, Suite A 1033, Mt. Pleasant Road, Evansville, Indiana 47711.

Coal is extracted from multiple seams utilizing both contour and mountaintop removal mining methods. The major coal seams mined are the Amburgy and the Elkhorn Nos. 2, 2�, and 3. Each seam ranges from 18 to 24 inches in thickness. The mine employs a total of 47 miners and normally operates two 12-hour shifts, seven days per week. The average daily coal production is 2,500 tons.

The overburden is removed from the coalbeds utilizing highwall drills, bulldozers, front-end loaders, rock trucks, and a Marion 201 electric powered shovel. The coal is transported by trucks to a rail loading facility.

The Mine Safety and Health Administration was conducting a complete health and safety inspection at the time of the accident.


DESCRIPTION OF ACCIDENT

At approximately 7:00 A.M. on May 11, 1995, Terry Newsome, maintenance manager, assigned work duties to the crew working on the Marion 201 electric shovel. The crew consisted of: Edgar St. Clair, mechanic (victim); Bart Adkins, greaser; Neil Bailey, shovel operator; and Fred Campbell, shovel operator. The crew was in the process of repairing the shovel which had become inoperative on May 9, 1995. A large retaining nut that held the center pin in place had loosened, allowing the center pin to drop six to eight inches from the correct position.

The retaining nut was tightened to the extent possible using portable power tools. Final tightening of the nut was to be accomplished by blocking it to prevent movement and then rotating the top section of the shovel. At approximately 10:00 a.m., Terry Newsome energized the electric shovel by engaging the vacuum circuit breaker located in the main substation. The top structure of the shovel was then rotated to attain the correct torque on the retaining nut. Newsome instructed St. Clair and Adkins to install the access plate that covered a set of low- voltage collector rings on the bottom structure of the shovel. After the access plate had been installed, St. Clair noticed a small piece of a high voltage porcelain insulator lying on the ground. He informed Adkins that there was "trouble upstairs", pointing toward the high voltage compartment. St. Clair climbed up through the access hole to the compartment containing the shovel's high-voltage collector rings. While in this compartment, he came in contact with the energized collector rings.

Adkins was removing cribbing from under the shovel when he heard a noise and saw a blue flash of light in the vicinity of the access hole. Adkins then looked through the access hole on the bottom of the machine and observed the lower part of St. Clair's body protruding from the high voltage collector ring compartment. Adkins called St. Clair's name and asked if he was alright. When he received no response he realized that St. Clair had sustained an electric shock. Adkins crawled out from under the shovel and activated the emergency stop switch located on the rear of the machine. Using the battery powered shovel elevator he went up to the part of the shovel where Newsome and the remainder of the crew were working and informed Newsome that St. Clair was injured. Newsome and Bailey boarded the shovel elevator and travelled to the ground level of the machine. Newsome then informed the crew not to go under the shovel until he made sure that the entire machine was deenergized. Adkins called 911 from the cab of the shovel using the citizen's band radio while Newsome travelled to the substation and deenergized, locked out, and tagged the circuit supplying power to the shovel.

Adkins and Barry Bartley, greaser, climbed up through the access hole to the location of the victim. They removed St. Clair from the collector ring compartment and placed him on the ground behind the shovel. He was checked for vital signs and no pulse was found. Bailey administered CPR until the ambulance arrived. St. Clair was transported by Elkhorn City Ambulance Service to Pikeville Methodist Hospital where he was pronounced dead on arrival.


PHYSICAL FACTORS INVOLVED

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

  1. The Marion 201-M electric shovel involved in the accident was equipped with a 22 cubic yard bucket. The machine was used for loading overburden material prior to the removal of the coal.

  2. The shovel received 7200 volt, 3-phase electric power from a 2000 KVA company-owned substation located approximately one- half mile from the shovel. Substation power was supplied by the local utility, Kentucky Power Company. Elevated open transmission wires were used to transmit power to within 800 yards of the shovel where the open wires were terminated at a set of high voltage disconnects. Power transmission continued to the shovel via a Romex #2 AWG, 8 KV transmission cable.

  3. Collector rings, mounted inside the shovel's lower structure, transmitted the 7200 VAC to the upper, rotating portion of the shovel. Transformers located within the shovel converted the 7200 VAC down to 550 VAC, 240 VAC and 110 VAC.

  4. The electrical accident occurred in the high voltage collector ring compartment.

  5. Disconnects in the high voltage system were at the following locations:

    1. the high voltage substation approximately one-half mile from the shovel and

    2. a set of pole mounted disconnects approximately 800 yards from the shovel.

  6. There was no visible or other type of disconnect on the shovel between the point where the cable entered the machine (on the lower structure) and the main high-voltage disconnect (located in the upper structure).

  7. The ceiling to floor clearance in the high voltage collector ring compartment was 25 inches. The distance between adjacent collector rings was 7.5 inches. The collector rings were 2.5 inches wide. The high voltage collector ring compartment was situated around the center pin of the machine and was approximately 10' in diameter.

  8. Evidence suggests that the victim came into contact with at least two phases of the high voltage system. Arc spots were present on the collector rings where the victim was found.

  9. The instantaneous flags on the Westinghouse CO-9 relays were activated on phases 1 and 3. Activation of the instantaneous units of these relays tripped the high voltage breaker at the time of the accident. Subsequent tests indicated that these relays tripped at approximately 900 amps. The current transformers were set to a 60:1 ratio and the instantaneous unit on the overcurrent relays were found to trip at 15 amps (60 X 15 amps= 900 amps).

  10. The grounded phase relay (ASEA Brown, Boveri solid state relay) was connected to a current transformer with a ratio of 9:1. The time setting on the grounded phase relay was 0.5 seconds and the current tap was on 0.1 amps.

  11. The high voltage vacuum circuit breaker apparently tripped in 3 to 29 cycles after the victim contacted the collector rings. This conclusion was reached because the phase to ground relay, which was adjusted to trip in 0.5 seconds (30 cycles), was not activated.

  12. The victim was employed as a mechanic. His primary job responsibility was repairing and maintaining the Marion 201-M electric shovel.

  13. The victim was not qualified to perform electrical work under 30 CFR, Part 77.103.


CONCLUSION

The victim received a fatal electrical shock when he came in contact with a set of 7200 VAC collector rings in the high voltage compartment of the Marion 201 shovel. The accident occurred when the victim entered a location where high voltage circuits had not been locked out, grounded, and tagged.


VIOLATIONS

The following citations/orders were issued during this investigation:

  1. A 103K Order (No. 4512346) was issued by MSHA to insure the safety of persons working around the electrical equipment and machinery on the mine site.

  2. A 104 (a) Citation (No. 4593212) was issued for electrical work being performed by a person unqualified by the definition of 77.103 and for failure to lock and tag the circuit out-of-service. The citation was issued under Title 30 CFR, Part 77.501.

  3. A 104 (a) Citation (No. 4491981) was issued for failure to de-energize and ground the high voltage phase conductors before work was performed. The citation was issued under Title 30 CFR, Part 77.704.



Respectively submitted:

Buster Stewart
Coal Mine Safety and Health Specialist

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 [FAB95C13]