A fatality at a California mine was caused by a contractor’s failure to ensure that bulldozer operators wore seatbelts while using heavy equipment, according to a federal investigation.
The U.S. Mine Safety and Health Administration (MSHA) determined that the fatality could have been prevented if the bulldozer operator would have been wearing a seat belt when he backed over the edge of a highwall.
Co-worker tried to warn him that he was heading toward edge
John Hatfield worked as a bulldozer operator for LB3 Enterprises Inc., a contract mining company. LB3 was contracted by CalMat Co. to perform mining activities at the Chula Vista surface mine located in San Diego County, California.
On June 22, 2023, Hatfield and an excavator operator were assigned to get a ramp area ready for drilling and blasting operations.
This particular ramp was about 100 feet wide. Hatfield used his bulldozer to push material over the edge of the ramp by backing the bulldozer up about 20 feet, dropping the blade and then moving forward to push the material over the edge. Meanwhile, the excavator was used to remove large boulders.
Hatfield and the excavator operator were called away from the ramp at 1 p.m. for a planned blast. They returned to continue their work at 1:40 p.m. About an hour later, the excavator operator noticed Hatfield backing his bulldozer toward the edge of the ramp’s highwall. The excavator operator honked his horn, flashed his lights and tried to wave to Hatfield to warn him that he was heading for the drop off.
However, Hatfield continued to drive backward toward the edge while looking forward. He never turned to acknowledge the excavator’s horn and flashing lights. The excavator operator saw Hatfield back over the edge of the highwall and disappear.
The excavator operator called for help via radio, and a 9-1-1 call was placed at 2:34 p.m. Several other workers went to the incident scene and found that Hatfield wasn’t in the seat of the bulldozer. He was found nearby and was pronounced dead by paramedics at 2:52 p.m.
Computer recorded 26 seat belt faults in 182 hours of operation
MSHA investigators examined Hatfield’s bulldozer but found no defects that contributed to the incident. The bulldozer had a backup camera that functioned normally, and Hatfield’s pre-operational inspection noted no problems. Investigators found that the bulldozer’s rollover protection structure received little damage from the fall. This structure would likely have protected Hatfield if he had remained inside the cab during the fall.
The bulldozer’s seat belt functioned properly when tested, according to MSHA. Both CalMat and LB3 had policies requiring the use of seat belts on mobile equipment. Hatfield was trained on those policies. Investigators weren’t able to determine whether Hatfield regularly used a seat belt. There was no record of Hatfield being counseled regarding his failure to use a seat belt while using mobile equipment.
Data recorded by the bulldozer’s computer revealed that there were 26 seat belt faults in the last 182 hours of operation, indicating that the seat belt wasn’t being used. Further, rescuers found Hatfield out of the operator’s seat at the scene of the incident. The bulldozer’s seat belt was found in the retracted position. All of this evidence pointed to the fact that Hatfield wasn’t wearing a seat belt at the time of the incident, MSHA said.
Contractor re-trained employees on seat belts
Investigators determined that the root cause of the incident was the contractor’s failure to ensure that workers wore seat belts while operating heavy equipment.
LB3 has since re-trained its employees in the use of seat belts.
