CHARLESTON (AP) — A West Virginia underground mine operator did not follow proper safety procedures prior to the death of a maintenance worker whose brakes failed on his electric utility vehicle and it lost control and crashed, according to a federal regulator.

The U.S. Mine Safety and Health Administration issued a final report in the Nov. 1 death of Brian Wallen, 49, an assistant maintenance shift supervisor at Mingo Logan Coal LLC’s Mountaineer II Mine in the Logan County community of Sharples.

MSHA said the mine operator did not maintain the vehicle in a safe operating condition and failed to remove it from service.

“The mine operator engaged in aggravated conduct constituting more than ordinary negligence,” the report said.

Wallen, who had 25 years of mining experience, died when the brakes failed and the vehicle crashed and overturned at the bottom of a slope. MSHA said investigators found that the left rear brake caliper was broken off prior to the accident and was tied to the vehicle’s frame with a plastic cable zip tie, the parking brake did not operate when activated and the left rear wheel bearings were worn and damaged.

MSHA noted the mine operator had identified the vehicle as having a defective braking system on three separate days just before the accident.

Less than 24 hours before the accident, another worker began losing control of the same vehicle as it went down a slope but was unable to stop it until it reached level ground, according to the report. The vehicle was towed to the surface, but an electrician who then worked on the battery was not told of any issues with the braking system and did not conduct any tests or repairs on it. The electrician later informed a shift supervisor that the vehicle was ready again for use.

The operator was ordered to conduct pre-operation checks for safety defects on mobile equipment and to remove equipment from service immediately if safety defects are found.