Inspection Detail

Inspection: 126037944 - C R Briggs

Inspection Information - Office: San Bernardino Mining &Tunneling District Office

Investigation Summary

Between 1:00 and 3:00 p.m. on March 22, 2001, Employee #1, an employee of C. R. Briggs Corporation, was assigned to a repair task at the crusher shop. At this mine site, C.R. Briggs Corporation operates an open pit gold mine located approximately 30 miles from Trona, California. Ore containing gold is extracted, crushed, leached in cyanide ponds, melted and the gold extracted and gold ingots cast on the mine site. Employee #1 and another mechanic were in the process of making weld repairs to a metal plate. The plate was approximately 50-inches in width by approximately 60-inches in height by approximately 5-inches in thickness, and weighing approximately 1600 pounds. Just prior to the injury, the metal plate was positioned on a concrete floor, standing vertically, and stabilized by a attaching a wire rope sling, approximately 0.25-inch by 36-inchs by 48-inches, to the metal plate and a boom truck. During a metal removal process called "air-arc", the wire rope sling was burned in two pieces. The wire rope sling was connected by a 0.60-inch screw pin shackle. The welding machine was set to between 400 and 450 amps. The factor that caused the accident was that the wire rope sling did not have the current carrying capacity to carry the amperage of the welder. The welder grounding electrode clamp was attached to the screw pin on the shackle. When the wire rope sling broke, the metal plate started to fall toward Employee #1. Employee #1 attempted to jump back, but the metal plate struck both his feet. The result was a broken right foot and the crushing of the left foot and ankle. Employee #1 was hospitalized with fractures.

Keywords: FRACTURE, WIRE ROPE, WELDER, METAL SHEET, STRUCK BY, SLING, ANKLE, FOOT