COAL MINE FATALITY - On Thursday May 11, 1995, a mechanic was electrocuted during maintenance work on a large electric shovel. The shovel had been out-of-service for two days for repair. The large retaining nut for the shovel's center pin had loosened allowing the center pin to drop about six to eight inches from the pin's correct position. The nut was partially tightened using a portable power units. During the repair activity the electrical power had been removed from the shovel. To further tighten the nut to the correct torque the nut was blocked from movement, the electrical power restored, and the shovel body rotated. After the nut was tightened, the mechanic and an assistant reinstalled a belly pan plate which covered a set of low-voltage slip rings. Upon installation of the belly plan, the mechanic noticed a small piece of a high-voltage porcelain insulator on the ground. While the shovel remained energized, the mechanic crawled through a vertical 20-inch diameter access hole that led to the compartment containing the shovel's high voltage collector rings. In the compartment, the mechanic came in contact with all three energized phases of the 7,200 volt circuit of the collector rings.
This is the 13th coal mine fatality in 1995. As of May 11 last year there had been 18 fatalities. This death is the second classified as ELECTRICAL in 1995.
Line drawing of the accident scene
For more information:
MSHA's Fatal Accident Investigation Report [FTLC9513]
