MSHA said it was notified by Pine Ridge Coal only after the roof fall was found by one of its inspectors, who subsequently cited the violation.

Regulations stipulate that mine operators who know of a reportable roof fall must notify MSHA within no more than 15 minutes.

Administrative Law Judge Thomas McCarthy decided to triple the fine in this case.

“The judge found that Pine Ridge did not have an objective good faith belief that the roof fall was not reportable, particularly given that the accident required the operator to abandon the mine entry altogether and to block off access to prevent travel through that section of the mine,” MSHA said.

“The judge also held that the roof fall had impaired ventilation and had impeded passage in the mine.”

Assistant secretary of labor for mine safety and health Joseph Main said the Mine Act required prompt notification of roof collapses.

“Operators must take seriously their reporting obligations and when they don't must deal with the consequences," he said.

MSHA said Pine Ridge had a history of roof falls at this mine.