Ventilation is one of the most critical factors when planning for longwall mining. It involves consideration of provisions for adequate gateroad ventilation; face ventilation, including methane and dust control; bleeder system design for control of gases in and around the gob areas; and intake air escapeway and haulage isolation requirements of federal regulations. Air ventilation for US underground coal mines includes face ventilation and the gob and bleeder ventilation systems. There are several health, safety, and environmental issues associated with longwall mining, including methane, dust, noise, and surface subsidence. Since methane emission and dust increase with coal production, they are critical factors in high production longwalls. Traditionally, air ventilation is used to dilute methane and dust concentration. Each longwall mine is required to submit a ventilation plan and a supplement to the ventilation plan to its respective Mine Safety and Health Administration district manager. The approved plan must be designed specifically for the individual mine conditions and mining system.