Reverse Circulation (RC)
Reverse Circulation Drilling (RC) is a technique which allows for full recuperation of the soil and rock samples, without any wall contamination. Performed by using a triblade, tricone or a down-hole hammer, the samples are evacuated through the face of the bit into the inside tube of a dual wall drill steel so that they never come in contact with the borehole wall. This technique is both cost effective and quick. The borehole usually has a diameter of 150 mm and a depth of 50 to 200 meters.