These methods to improve ventilation airflows and ventilation efficiencies in large-opening mines include the use of the NIOSH Estimator to estimate the airflow required for proper DPM dilution, use of propeller fans where possible, and utilization of mine planning layouts that incorporate long stone pillars, stoppings, and auxiliary fans to direct airflow to active face areas. The use of long stone pillars is particularly effective in reducing leakage between intake airways and return airways, thus allowing the maximum amount of air produced by the main mine fan to reach the face area. Although various factors can impact face ventilation effectiveness, the best method to ventilate the face is to position an auxiliary fan outby the last open crosscut and in the furthest upstream entry, such that it blows through the intake entry. It is shown that auxiliary fans entrain and generate considerably more air quantity than the actual fan rating. Therefore, although actual conditions will dictate the proper position of the auxiliary fans, as a general rule, they should be located in the intake air, outby the last opening in the long pillar, entraining as much intake air as possible. This will lead to increased fresh air quantities moving toward the face. To reduce recirculation, the fan should also be located in the furthest upstream entry to create air movement that is traveling in the same general direction as the air being moved by the main mine fan.