Coal remains one of the principal sources of energy for the United States, and the nation has been a world leader in coal production for more than 100 years. Ac

Employment and production in the Appalachian coal industry have plummeted over recent decades. But the lethal black lung disease, once thought to be near-elimin

Coal will continue to provide a major portion of energy requirements in the United States for at least the next several decades. It is imperative that accurate

Throughout the mining and processing of minerals, the mined ore undergoes a number of crushing, grinding, cleaning, drying, and product sizing operations as it