Turn the throttle lever gradually and drill at a slow speed until the hole is collared. The drill should be kept at right angles to the work until the hole is collared, then repositioned for angle drilling. Always apply sufficient down pressure to keep the tool from bouncing.
[pdf] In hard rock mining and quarrying, this is achieved through a controlled process of drilling and blasting. A blast hole drill rig is a specialised piece of equipment that creates a series of holes in a specific pattern, depth, and diameter across a section of rock known as a “bench.”
[pdf] There are many different types of drill bits, each designed for a specific purpose. However, the main factor determining which drill bit to use on rock is the hardness of the material. The harder the rock, t.
[pdf] 
