Case Studies

In the 2018 drill program, 67 % of targets were drilled using directional methods, with the Zero-trip Wedge used on 92 % of these, and the traditional multi-trip method was used for the remainder. The multi-trip wedges were used in the same mother hole, due to the exceptionally poor ground conditions and some concern was expressed about using the ‘experimental’ wedge. However, these boreholes were lost and, ultimately, a Zero-trip Wedge was attempted and proved successful. During use, the Zero-trip Wedge failed to anchor three times. This was typically found to be caused by ground conditions, such as cave or rubble from higher in the mother hole, and on each occasion a second attempt proved successful. Overall the Zero-trip Wedge was shown to have a 100 % success rate. Savings The advantages of the Zero-trip Wedge come down to time. Its installation took place in one shift, regardless of depth, while the wedge cut was also typically completed in Shift 1 for boreholes with a wedge depth of 600 m to 900 m. The average for 2018 with the Zero-trip was: one shift setting the wedge, six shifts directional drilling, one shift reaming, for a total of eight shifts. An average breakdown of the time on directional drilling with the multi-trip from historic mother holes was: 3.5 shifts setting wedge, 6.5 shifts directional drilling, one shift reaming, giving a total of 11 shifts.

Over the 2018 period, directional drilling with the Zero-trip Wedge resulted in 75 shifts being saved when compared to the standard method. Note: Where possible, only mother holes where both zero and multi-trip wedges were installed have been used for time-saving calculations.