RC drilling today produces samples of high quality and reliability. Dual-pipe RC drilling utilizes double drill rods where air is passed down the hole through the outside annulus and into the hammer. Drill cuttings are cleared from the bit by the air and travel up through the centre tube of the drill rods remaining free from contamination.
HIGH RATE OF PENETRATION
A big advantage of RC is its high rate of penetration. Penetration rates often exceed 80 m per shift depending on ground conditions. The speed of drilling can often mean big cost savings compared to slower drilling methods.
GOOD IN BAD GROUND
RC drilling is relatively insensitive to ground conditions, which may be difficult or slow to penetrate using other methods. Dual-pipe RC was originally developed as a method to drill “nightmare” geological formations (such as permafrost, glacial till, broken rock, etc.) where conventional drilling methods were costly and ineffective.
RC drill cuttings are transported to surface inside the centre tube of the dual pipe. Because of this sample recovery is usually very good with high recoveries of both fines and clays.
Reverse circulation drilling has several environmental advantages. First and foremost, RC mostly requires no water for rock drilling. This is a benefit in areas with limited or sensitive water supply.
In addition, frozen water sources and waterlines can make winter drilling both tricky and expensive, if not impossible. In certain areas, like the arctic tundra, environmental permitting is easier for winter drilling when the ground is frozen and unlikely to be disturbed. Light-weight RC makes winter drilling in the arctic a viable option.
By using compressed air to extract rock fragments sample,the samples travel through rods to a sample splitter at surface, avoiding all contact between the samples and the borehole wall that allows samples to be retrieved with minimal contamination.
SOLLROC RC BIT model RE547:
Buttons * button diameter
Shroud diameter (mm)
SOLLROC Reverse Circulation drilling (RC) ,from size 3’’ to 5.5’’, is a technique of drilling that uses dual wall drill rods that consist of an outer drill rod with an inner tube. By using compressed air to extract rock fragments sample,the samples travel through rods to a sample splitter at surface, avoiding all contact between the samples and the borehole wall that allows samples to be retrieved with minimal contamination,which is mainly used in deep hole exploration and mining grade control.