Crawler drill Rig

The diagram illustrates a simple, relatively inexpensive crawler-mounted, pneumatic (DTH) drill rig. The crawler, driven by air-motors, tows a separate compressor. This rig would be suitable for a smaller quarry of lower output. The percussion hammer is located within the drill stem immediately above the bit--hence 'down-the-hole' (DTH). It is pneumatically actuated. DTH drilling is claimed to give better directional control of the blast-hole whilst maintaining effective penetration rates even in difficult conditions e.g. faulting, interbedded rocks, jointing etc. Exhaust air from the hammer flushes the blast hole to remove cuttings.