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Metal and Nonmetal Mine Safety and Health

Accident Investigation Report
Surface Nonmetal Mine

Fatal Slip/Fall Accident

Busy Bee Electric, Incorporated
Contractor ID No. 6XC
Irwindale Plant
United Rock Products Corporation
Irwindale, Los Angeles County, California
Mine ID No. 04-01763

August 19, 1997


Timothy B. Hannifin III
Mine Safety and Health Inspector

David A. Kerber
Mine Safety and Health Inspector

Mine Safety and Health Administration
Western District
2060 Peabody, Suite 610
Vacaville, California 95687

James M. Salois
District Manager


Mark William Hoffman, welder, age 46, was seriously injured at about 12:50 p.m. on August 19, 1997, when he slipped and fell while working on a dredge that was under construction. He died the following day. Hoffman had approximately 25 years experience as a welder and had worked at the mine for 13 days. He had not been trained in accordance with 30 CFR Part 48.

MSHA was notified by a telephone call from the safety director for the mining company at 3:00 p.m. on the day of the accident. An investigation was started the following day.

The Irwindale Plant, an open pit sand and gravel operation, owned and operated by United Rock Products Corporation, was located at Irwindale, Los Angeles County, California. Operating officials were Arnold Brink, operations manager; William Cameron, safety director; Earl Wise, assistant operations manager; and Daryl Carlson, plant and maintenance superintendent.

At the time of the accident, a dredge was under construction at the No. 2 Pit. Rohr Corporation was the prime contractor and Busy Bee Electric, Incorporated (Busy Bee) was an electrical sub-contractor. Operating officials for Busy Bee were James R. Oehlschlaeger, president; and James A. Minneman, foreman. Hoffman was employed by National Onsite Personnel of Fort Wayne, Indiana, as a temporary employee of Busy Bee.

The Irwindale Plant was normally operated two 8-hour shifts a day, five days a week. Thirty-five persons worked at the mine. A total of ten contractor employees were on site. They worked an 8- to 10-hour shift each day, five days a week.

Sand and gravel was mined by a front-end loader from a single bench. Material was conveyed by belt to the plant for processing. The finished products were sized sand and gravel used primarily for construction aggregate.

The last regular inspection of this operation was completed on August 16, 1997. Another regular inspection was conducted following this investigation.

Physical Factors

The dredge involved in the accident was of steel construction and was equipped with twin 16-yard clam shell buckets. It was 105.6 feet (32 meters) long, 105.6 feet (32 meters) wide, and 46.2 feet (14 meters) high. Construction had started on the dredge in July, 1997.

The Telsmith crusher structure was mounted on the dredge deck and measured 30 feet wide by 55 feet high. The two clam shells would dump material onto one of two grizzlies, which are devices for coarse screening or scalping, located on each side and about 12 feet above the crusher. Chutes from the two grizzlies faced each other and directed material into the jaw crusher.

The I-beam from which the victim fell was nine inches square and structurally connected the two grizzlies. A 1 �- by 1 �-inch piece of metal stock was welded on the top center of the beam and extended the full length.

Safety harnesses, belts, lanyards, and ladders were available on site. The weather was warm and winds were calm. The dredge was floating in approximately three feet of water.

Description of Accident

On the day of the accident, Mark Hoffman (victim) reported for work at 6:00 a.m., his regular starting time. Hoffman worked on shore during the morning, welding supports for conduit. After lunch, Hoffman was instructed by James Minneman, foreman for Busy Bee, to spot weld cable trays into position on the dredge.

Minneman, David Dalessandro, apprentice electrician, and Calvin Cassidy, journeyman electrician, were hoisting sections of cable tray from the main deck to a catwalk located above the chutes and jaw crusher, using a rope. After a cable tray was pulled into position alongside the catwalk, Minneman noticed Hoffman lying on one of the two chutes from the grizzlies to the jaw crusher. Minneman told Hoffman to move aside so the cable tray would not accidentally fall on him. Minneman then went to the main deck to obtain clamps to secure the trays in place.

Hoffman climbed over or through the handrail along a walkway on the main structure of the dredge and onto the I-beam between the two grizzlies. Minneman was returning with the clamps and heard Dalessandro shouting that Hoffman was falling. Minneman saw Hoffman, who had apparently lost his balance, fall from the I-beam, a distance of about 12 feet, to the crusher.

Minneman located a board and placed it under Hoffman to prevent him from slipping into the crusher. Jeffrey Chandler, Rohr Corporation supervisor who was on shore, called the local 911 emergency assistance number. Hoffman was conscious but incoherent when paramedics arrived approximately ten minutes later. He was air lifted to a local hospital where he died the following day.


Failure to provide a safe means of access was the direct cause of the accident. Failure to use safety belts and lines contributed to the severity of the accident.


Order No. 4524348
Issued to United Rock Products Corporation on August 20, 1997, under the provisions of Section 103(k) of the Mine Act:

This order was issued to ensure the safety of the persons during the examination/investigation and to determine that the dredge was safe so that employees could return to work. The order was terminated on August 21, 1997.

Citation No.4524389
Issued to Busy Bee Electric, Incorporated on August 21, 1997, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 56.15005:

On August 19, 1997 at approximately 12:50 p.m. an employee fell 12 feet into a jaw crusher which was under construction, resulting in fatal injuries. The employee was not wearing a safety belt and line.

Citation No. 4524390
Issued to Busy Bee Electric, Incorporated on August 21, 1997, under the provisions of Section 104 (a) of the Mine Act for violation of 30 CFR 56.11001:

A safe means of access was not used when traveling from the main structure and walkways of the dredge to the chutes and grizzlies above the jaw crusher. A welder was fatally injured when he fell from an "I" beam into the jaw crusher. The welder had apparently crawled through an existing handrail and stepped over a 17-inch gap between the walkway and grizzly to gain access to the area, creating a falling hazard.

//s// Timothy B. Hannifin III
Mine Safety and Health Inspector

//s// David A. Kerber
Mine Safety and Health Inspector

Approved by: James M. Salois, District Manager

Related Fatal Alert Bulletin:
Fatal Alert Bulletin Icon [FAB97M45]