Book excerpt: 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. According to U.S. Energy Information Administration projections to 2050, coal is expected to be an important energy resource for the United States. Additionally, metallurgical coal used in steel production remains an important national commodity. However, coal production, like all other conventional mining activities, creates dust in the workplace. Respirable coal mine dust (RCMD) comprises the size fraction of airborne particles in underground mines that can be inhaled by miners and deposited in the distal airways and gas-exchange region of the lung. Occupational exposure to RCMD has long been associated with lung diseases common to the coal mining industry, including coal workers' pneumoconiosis, also known as "black lung disease." Monitoring and Sampling Approaches to Assess Underground Coal Mine Dust Exposures compares the monitoring technologies and sampling protocols currently used or required by the United States, and in similarly industrialized countries for the control of RCMD exposure in underground coal mines. This report assesses the effects of rock dust mixtures and their application on RCMD measurements, and the efficacy of current monitoring technologies and sampling approaches. It also offers science-based conclusions regarding optimal monitoring and sampling strategies to aid mine operators' decision making related to reducing RCMD exposure to miners in underground coal mines.