|
DEPARTMENT OF LABOR MINE SAFETY AND HEALTH ADMINISTRATION Metal and Nonmetal Mine Safety and Health Accident Investigation Report Surface Nonmetal Mine Fatal Electrical Accident Plant #1 I.D. Number 44-02786-ZZZ Chemstone Corporation DBA Global Stone James River Buchanan, Botetourt County, Virginia July 21, 1996 by Dennis Yesko Supervisory Mine Safety and Health Inspector and Charles J. Weber Mine Safety and Health Inspector Special Investigator Mine Safety and Health Administration Northeastern District Office 230 Executive Drive, Suite 2 Cranberry Township, Pennsylvania 16066-6415 James R. Petrie District Manager GENERAL INFORMATION Eric Bowden, age 15, was fatally electrocuted at approximately 11:00 a.m. on July 21, 1996, while fishing with his brother and several friends along a section of the James River bordering a crushed stone operation. Three of the youths had fished this river the week prior to the accident. A security guard had given them permission to enter the mine for access to the river on both occasions. MSHA was notified at 1:15 p.m. on the day of the accident by John Michener, vice president and general manager. An investigation was started the same day. Plant #1, was an open pit, multiple bench, crushed stone operation with an associated mill. It was owned and operated by Chemstone Corporation DBA Global Stone James River, and was located in Buchanan, Botetourt County, Virginia. The principal operating official was John Michener. The plant was normally operated 2 to 3, 8-hour shifts per day, 5 to 6 days per week and employed a total of 30 persons. Chemstone Corporation purchased the company from James River Limestone Co., Inc., approximately 3 weeks prior to the accident. Limestone was drilled, blasted, and then loaded into haulage trucks utilizing a track hoe and front-end loader. It was transported to the mill where it was crushed, sized, and ground. The finished product was loaded into railroad cars and over-the-road haulage trucks to transport to industrial and agricultural customers. The last regular inspection was completed on January 18, 1996. Another regular inspection was completed on August 15, 1996, after the conclusion of this investigation. Physical Factors Electrical power for the plant was provided from a substation owned by Virginia Electric Power Company located on mine property. Substation transformers were wye solid grounded on both primary and secondary sides. The substation provided 4160 volt alternating current (VAC) to three 75 kilo volt amp transformers owned by the mine operator located nearby. These ungrounded delta transformers reduced the voltage to 480 VAC. A water pump, used periodically to provide water to the plant, was mounted on a small, steel, rail car that sat on a pair of rail tracks elevated about 3 feet above the ground. The tracks began at the top of a slope and ended approximately 11 feet from the river. The rail car was about 14 feet from the end of the tracks. A 3/8-inch wire rope extended from the tracks into the river and was used to tie-off the pump's foot valve. An electrical path existed through the wire rope, rail tracks, and steel rail car. The water pump was provided with a 10 horsepower, 460 VAC, 12-amp, Baldor motor. The pump's power cable was a type UF-B sunlight resistant cable, size 10/3 with ground, rated 600 volts with a 30-amp carrying capacity. It ran from a disconnect switch in the old mobile equipment shop, approximately 247 feet, to a disconnect switch at the pump. The first 163 feet, the cable ran through a 24 to 30 inch steel culvert used to drain water run-off from the plant. A stream of water, approximately 8 to 10 inches wide and 2 inches deep, flowed in the culvert. The stream extended from the end of the culvert, approximately 43 feet to the river. The stream, and the aforementioned 3/8-inch wire rope, entered the river within approximately 18 inches of each other. About 15 feet of the pump's power cable containing a splice, lay in the stream where it flowed from the culvert. The splice and the cable's insulation had been damaged by the abrasive action of sand and small stones carried by the stream. Reportedly, the cable had been replaced several times before due to damage. The wires in the splice were separated, except for the black conductor loosely held together with a wire nut and small amount of electrical tape. The ends of the other conductors were bare and showed no evidence of being secured with either wire nuts or lugs. The splice showed no evidence of having been insulated with shrink tubing or other moisture resistant insulation. About 2 feet from the splice towards the pump, approximately 9 feet of insulation had burned off the conductors laying in the stream. The bare power and ground conductors were in contact with each other, and the black and red power conductors had fused together. Since the ground conductor was separated at the splice, there was no effective path back to the ground bed at the plant's transformers. The ground conductor, however, was connected to the pump's motor frame and control switch, and a path for current flow to earth existed through the the steel rail car on which they were attached and the 3/8-inch wire rope leading into the river. A second path existed where the splice and bare conductors lay in the stream. The operator had not conducted continuity and resistance tests of the pump's grounding system, although they had tested the resistance of the ground bed at the plant's transformers. Short circuit protection was provided for the pump's motor circuit by two fused disconnect switches, one at the old mobile equipment shop to protect the cable, and the other at the pump to protect the motor. Each disconnect switch contained three renewable link fuse barrels, one fuse for each phase. Each fuse was designed to contain one 30-amp link, and the fuses at the pump's disconnect switch were found to be linked accordingly. The fuses at the old mobile equipment shop, however, were double linked and each contained two 30-amp fuse links in parallel, equating to 60 amps. The calculated maximum fuse size to protect the circuit against excessive overload is 25 amps (National Electrical Code, Tables 430-150 and 430-152). The voltage at the disconnect switch in the old mobile equipment shop measured 472 VAC on each phase. The motor control switch at the pump was in the off position at the time of the accident. No electrical faults were found in the pump's motor. Description of the Accident On the day of the accident, Eric Bowden, victim, entered the mine property at about 8:45 a.m., along with his brother, Edward and three friends; John Beck, Shawn Cofer, and Bryan Burke. David Frazier, a contract security guard, gave the five permission to go fishing along the James River, which bordered the mine's property. The youths proceeded down the roadway along the river. After heading up river, the group split up. At about 11:00 a.m., Edward Bowden was fishing with Burke when they heard Eric Bowden screaming upstream. They ran to his aid and found him lying in shallow water near the shore. They attempted to pull him out of the river, however, they kept getting shocked whenever they stepped into the water. They used tree branches and an old V-belt to pull him near the shore and his brother was able to pull him from the water. Eric Bowden was unresponsive and did not appear to be breathing. His brother immediately began administering CPR while Burke ran to the scale house to get help. Burke informed the guard, Bruce W. Gilliam, that one of his friends was electrocuted in the river. Gilliam called 911 at approximately 11:15 a.m., and remained at the scale house until help arrived. The rescue squad responded to the call and arrived at the scene at approximately 11:25 a.m. They continued CPR and transported Eric Bowden to a local hospital via ambulance. Bowden never regained consciousness and at 12:40 p.m., was pronounced dead. The week prior to the accident, Edward Bowden, Burke, and Beck were fishing in the area where the accident occurred. Burke recalled hearing a low intermittent growling sound. When he stepped into the river, he reported that he received a sudden shock that caused him to fall into the water. The river current carried him downstream and out of the field of electricity. He stated that he went to report the incident to the company's security guard, but that no one was at the main gate and he did not pursue it further. No one mentioned this prior incident to the security guard when they arrived on the mine property the morning of the accident. Conclusion Electrical faults, resulting from improper installation of the 480 VAC water pump power cable and circuitry, were the primary cause of the accident. The faults had energized the ground conductor to the pump, and a path for current flow to earth existed through a wire rope which ran into the river at the site of the electrocution. Factors contributing to faults were: 1. The power cable to the pump was not protected from mechanical damage caused by the abrasive action of the sand and small stones carried by the stream coming out of the culvert. Violations Order No. 4439687 Verbally issued on July 21, 1996, under the provisions of Section 103(k) of the Mine Act to protect personnel pending an investigation by MSHA. The order was reduced to writing and served to the mine operator on July 22, 1996. This order was terminated on completion of the onsite investigation on July 24, 1996. Citation No. 4439691 Issued on August 13, 1996, under the provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.12001: Order No. 4439692 Issued on August 13, 1996, under the provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.12013(b): Order No. 4439693 Issued on August 13, 1996, under the provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.12013(a): Order No. 4439694 Issued on August 13, 1996, under the provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.12013(c): Order No. 4439695 Issued on August 13, 1996, under the provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.12028: Order No. 4439697 Issued on August 13, 1996, under the provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.12004: //s// Dennis A. Yesko Supervisory Mine Safety and Health Inspector //s// Charles J. Weber Mine Safety and Health Inspector, Special Investigator Approved by: James R. Petrie, District Manager Related Fatal Alert Bulletin:  [FAB96M30]
|
