Air Core Drilling
his is an inexpensive method of exploration drilling that can be employed when safe removal of sample material is paramount. Where possible, it is preferred over RAB (Percussion rotary air blast drilling) drilling and unlike the diamond drilling method, which withdraws a small diameter core of rock from the orebody, air core drilling is much faster and more cost-effective.
Air core drilling relies on compressed air to flush cutting samples out of your drill holes. This enables the safer collection of samples without unnecessary damage to the surrounding area and results in a more effective analysis sample. It is often used in first pass exploration drill programs to provide accurate samples.
Reverse Circulation Drilling
RC drilling is similar to air core drilling, in that the drill cuttings are returned to the surface inside the rods. RC drilling is a quick cheap first pass exploration hole option, it achieves better penetration than air core drilling; it is cheaper than diamond coring and is thus preferred for most mineral exploration work.
Reverse circulation is achieved by blowing air down the rods, the differential pressure creating air lift of the cuttings up the inner tube which is inside each rod. It reaches the bell at the top of the hole, then moves through a sample hose which is attached to the top of the cyclone. The drill cuttings travel around the inside of the cyclone until they fall through an opening at the bottom and are collected in 1m intervals into a sample bag.