The company has planned site-specific training at the mines to reiterate to crews that they are expected to follow the law. Operations will also review past violations and examine best practices to eliminate future violations.

“Despite considerable training, there have been recent instances where our miners were not doing the right thing as they had been trained to do,” Massey chairman Don Blankenship said.

“The idling of production reinforces our philosophy that safety is first and production is second.”

US Mine Safety and Health Administration officials did not make public comment on the company’s move.

Massey is at the center of a civil investigation by federal authorities regarding the Upper Big Branch explosion in April that killed 29 workers. Blankenship has been accused by some of putting production before worker safety.

Massey’s mines are located in West Virginia, Kentucky and Virginia, and are mostly longwall and room and pillar operations.