According to the MSHA, similar circumstances contributed to each accident, with common factors including visibility in lower seam heights, low equipment operator seat position, moving machinery in the direction of batteries, and stacking and storing supplies on machines. The use of opaque or non-transparent ventilation curtains was also a common factor in the incidents.

MSHA officials are asking mine operators to evaluate the potential for similar accidents at their mines and implement preventive measures. Some of those best practices include utilization of clear ventilation curtains, as well as ceasing the practice of stacking or storing anything atop a mobile equipment unit.

Additionally, when mobile operators move through vent curtains, agency officials are urging the use of an audible warning device and the practice of stopping the machine before sounding that alarm.

The use of intrinsically safe strobe lights and reflective material on personnel can also assure optimum visibility for all when mobile equipment operators meet with pedestrian miners, MSHA said.

Officials also recommended that mines install engineering controls — including permissible camera systems and proximity detection systems mounted on mobile equipment — to improve equipment operator visibility while preventing other miners from being struck.