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.