A method of dust suppression in which thick foam is forced through the drill by means of compressed air and the foam and dust mixture emerges from the mouth of the hole in the form of a thick sludge. With this method the amount of dust dispersed into the atmosphere is almost negligible and the amount of water used is about 1 gal/h (3.8 L/h). Approx. 30 to 50 ft (9 to 15 m) of drilling can be done with one filling of the unit.