Ventilation to the working areas is accomplished with bulkheads, curtains, and waste rock walls foamed at the top to separate intake from exhaust air. Production panels utilizing diesel-powered haulage equipment require auxiliary fans in the last open breakthrough. There are usually three 120-cm (48-in), 11-kW (15-hp) fans at even intervals across the panels to help direct air. In addition, each heading or room is equipped with a 60-cm (24-in), 2.2-kW (3•hp) fan to direct air to each working face.