The honor, presented by the Wyoming Department of Workforce Services, Mines Inspection and Safety Division, marks 477 days without a lost-time injury and more than 2 million employee and contractor hours without a lost-time injury.

“I want to congratulate all those at Cordero Rojo mine on their continued commitment to safety, which this award reflects,” said Colin Marshall, Cloud Peak Energy president and CEO. “Cloud Peak Energy’s value of safety is an underlying principle that always guides our operations.”

“Together we have maintained a safety focus allowing us to qualify for an award like this,” added Joe Vaccari, Cordero Rojo mine general manager. “We will continue to be focused on performing our jobs safely and going home to our families safely at the end of each and every shift.”

In calendar year 2013, Cordero Rojo sold approximately 36.7 million tons of coal, ranking it as the third largest coal mine in the U.S. last year. Coal mined from Cordero Rojo is primarily shipped to electric utilities in the western, midwestern and southeastern United States.

Portfolio-wide last year, Cloud Peak Energy had one of the lowest All Injury Frequency Rates (AIFRs) of the top 25 U.S. coal producers, according to federal data.