On Wednesday, March 22, 2000, nine miners entered a mine via a rubber-tired mantrip. Approximately 400 feet into the mine, the mantrip encountered a steep grade (13.5 percent slope) with a wet bottom. The operator slowed the vehicle as he started down the slope; however, the vehicle lost traction and began to slide out of control. The operator released the brakes until the vehicle began to free wheel and then applied the brakes again. A popping noise was heard, and all braking power was lost. The mantrip traveled approximately 450 feet to the bottom of the slope, bounced off the right rib and was stopped abruptly by an offset in the left rib. Bolts connecting the right front wheel hub to the wheel were sheared prior to or during the accident. The left rear drive axle broke at the time of the accident. Two passengers in the front compartment received the most serious injuries and were taken by ambulance to the hospital. They were treated for minor injuries and released that evening.
- All electrical equipment, including brake components, must be frequently examined and maintained to assure safe operating condition.
- Equipment with brakes installed on the drive shaft requires specific examinations for the wheel hub bolts, the drive shaft, and axles.
- Equipment with braking system deficiencies must be removed from service.