Coal is a carbon compound that is formed from vegetation millions of years old. It is mined from the earth and is used for a variety of purposes including electricity generation, heat, cooking, and lighting.
Underground mining causes coal dust to accumulate and be aerosolized.
Inside the mine it may reach high levels. It can cause Black lung disease which is medically known as Coal Worker's Pneumoconiosis. It is primarily a disease of coal miners and their families. References Dr. John A. Hayes. Occupational Lung Disease.