On July 17, 2025, a miner at a surface limestone operation sustained serious injuries while performing repairs on a belt drive motor. During the repair process, the motor’s tensioning system was being adjusted when a ¾-inch diameter all-thread tensioner bolt failed, causing the bolt to break loose and strike the miner in the face. Spring-integrated designs with constant pressure and continuous vibrations pose potential safety concerns.
Read the full safety alert now: https://www.msha.gov/news-and-updates/alerts-hazards/filter/tensioner-bolt-failure-safety-alert