Thunder Basin Coal Co.’s Black Thunder mine surpassed 571 days and 4 million employee-hours without a single lost-time injury on November 20, 2009. “The dedicated workforce at Black Thunder mine has shown that together we can achieve a perfect zero in safety incidents,” said Kenneth Cochran, president and general manager, Thunder Basin. “This record-setting safety achievement highlights one of the core values upheld throughout the Arch Coal family of companies.” Black Thunder’s 1,600 employees produce roughly 12% of the annual U.S. coal supply from the single largest coal-mining complex in the world. Black Thunder mine is located in the Powder River Basin near Wright, Wyo.