Inspection Detail

Inspection: 305781999 - Sls&N Inc Dba Peck Road Gravel Pit

Inspection Information - Office: Van Nuys Mining & Tunneling District Office

Investigation Summary

At approximately 8:30 a.m. on March 1, 2004, the employer's operation consists of dredging sand and gravel from a pond. The Rohr dredge has two, 36-ton capacity clamshell-type buckets, which weighed approximately 16 tons each. The dredge operator sits in a small control room at an elevated location facing forward at the stern of the dredge in between the two overhead trolleys, which the buckets are attached. The buckets are lowered by two hoist cables approximately 100 ft to the bottom of the pond through open bays in the dredge platform. On the day of the accident, Employee #1 and Employee #3 were replacing one of the four hydraulic rams on the B-side bucket on the starboard side of the dredge. The ram to be replaced was on the forward, starboard side of the bucket. Employee #2 was operating the dredge. The bucket was lowered onto a section of the deck between the guardrail at the rear of the open bay and the guardrail at the stern of the dredge. It was then released from the hoist cables. A 0.375 in. chain was threaded through the eye of the starboard hoist cable and then was attached to a steel lifting eye on the side of the hydraulic ram with a choker hook. Employee #1 signaled Employee #2 via radio to take the slack out of the chain. This was done to prevent the 1,600 lb. hydraulic ram from falling when the upper and lower pins, which hold it in place, were removed from the hydraulic ram. Employee #1 stood on a small platform above the motor on the top of the bucket and spent about 5 minutes working to knock the pin out. At this time, the hoist lifted up suddenly. Because the chain was connected to the forward (inboard) corner of the bucket, it tilted towards the stern. The chain was rated at 7,000 lbs. and broke under the load, allowing the bucket to tip all the way over. It crashed through the stern guardrail and sunk to the bottom of the pond. Employee #1 was thrown into the water. He suffered a serious fracture to his left tibia and a deep laceration to his right tibia. His injuries most probably occurred due to striking the guardrail as the bucket broke through. He was transported via ambulance to a local hospital, where he spent 10 days and underwent surgery on both legs. Employee #1 stated that when the accident occurred he had not signaled the dredge operator to move the hoist line for 5 minutes.

Keywords: CHAIN, HYDRAULIC RAM, FRACTURE, GUARDRAIL, TIBIA, LACERATION, FALL