ABSTRACT
Apart from the standard drilling equipment, there are units and mounting systems on the market for special or very specific applications. Among these jobs, a few can be mentioned such as: drilling rock masses with overburden of a non-consolidated material and/or sheets of water, drilling rigs for shafts and raises, thermal and water jet drilling. Drilling can be carried out with top hammer or down-the-hole hammer, and consists of drilling through the overburden at the same time that the casing tube is passed down into the hole, to keep loose material from caving in and blocking the hole, so that drilling can proceed into solid rock. The equipment consists of an eccentric reamer bit that drills a hole with a larger diameter than the casing tube which descends as drilling advances. As between the casing tube and the blasthole walls there is friction which increases with depth, the rock drills should be used with high rotary torque.
