Ann: Diamond Production Continues Ahead of Plan at Lulo-LOM.AX, page-115

At Elledale we used a 1m diameter rig with slowly rotating drilling table that had a number of drill bits just below it. The voluminous cuttings were passed to a small dam and the excess water used again. About 1 or more tonne samples were processed through the plant with diamonds recovered so it was a continuos bulk sampling down hole exercise. They did not attempt great depths but got down at least 50m as I recall in weathered and fresher lamporite. Kimberlite and lamproites are not a hard as many rocks so it drills quite well. The holes left behind were interesting as tall grass quickly grew around them after rain and there was no dirt pile or fence to show where they might be - just a 1m wide deep shaft obscured by tall grass. Today Rio (CRA) may be more careful one would hope.