A mobile-type rotary drill used on opencast sites with no hard rock for drilling vertical blasting holes. It can drill a hole of 5 in or 6 in (12.7 cm or 15.2 cm) in diameter to depths of about 30 ft (9.1 m). Drilling is by means of a rotary cutting head with interchangeable cutting bits, the auger removing the cuttings from the hole. An overall speed of 30 ft/h (9.1 m/h) can be obtained.