Mechanic Steelyn Gary Kanouff, 28, was killed July 31 at Amerikohl Mining’s Amerikohl Strips in western Pennsylvania while checking a strut on a rock truck.

“He was removing the top cap of the strut when the cap loosened, allowing the truck frame to abruptly drop,” the agency said in its preliminary investigation findings released Tuesday.

“The victim was pinned between the top of the right front tire and the bottom of the fender.”

Kanouff, whose experience was gained entirely with the Amerikohl operation, was one of just eight employees on payroll at the small bituminous mine.

In an effort to prevent future similar incidents at other US operations, MSHA has urged workers to only perform maintenance and repairs after the machinery and components have been blocked against motion.

Crews should also determine if hydraulic hoses or components are supporting something or trapping pressure before loosening them to perform work.

Mine operators should ensure that the warning labels of machinery are visible, and any illegible or missing labels should be replaced as part of regular checks.

Additionally, MSHA said, the recommended safe work procedures of the manufacturer should always be consulted and followed for all maintenance tasks. Management should monitor work to ensure those procedures are followed and that safe work procedures are in place for specific tasks and machines mine-wide.

Finally, investigators reminded miners to consider all hazards before performing any job and implement any formal procedures that addressed hazards, and always made sure a safe location was kept while performing maintenance and repairs.

Kanouff was the 11th individual to be killed in US coal in 2013. Since then there have been two more.

The fatality is also the third machinery fatality this year.

Privately held Amerikohl is controlled by John Stilley, according to federal data, with the company’s main office address in Butler, Butler County.

According to federal performance statistics, the mine produced about 297,000 tons last year with 67,000 man hours worked. Its national fatal incidence rate was 0.0086 and non-fatal days lost rate was 0.98.

It has received just one 104(a) violation so far in 2013, and had none in 2012.