03/09/2012 04:03 EST | Updated 05/09/2012 05:12 EDT

Federal prosecutors announce charges, fines in Utah's 2007 Crandall Canyon mine collapse.

SALT LAKE CITY - Federal prosecutors have announced misdemeanour criminal charges and fines in Utah's 2007 Crandall Canyon mine collapse that killed nine people.

U.S. Attorney David B. Barlow in Salt Lake City said Friday that the mine operator, Pepper Pike, Ohio-based Genwal Resources Inc., an affiliate of Murray Energy Corp, has agreed to plead guilty to two counts of violating mandatory health and safety standards and pay a $500,000 fine.

Six miners died at Crandall Canyon in an August 2007 collapse so powerful that it initially registered as a 3.9-magnitude earthquake. Another cave-in 10 days later killed two rescuers and a federal inspector.

The operation was called off after drilling into the mountain found no sign of the men.