Revolutionary new drill rig
A revolutionary new drill rig that could revitalise Australia’s mining industry has undergone successful field trials in South Australia’s outback, bringing it a step closer to commercialisation.
The prototype coiled tubing drill rig, the RoXplorer®, was developed by the Deep Exploration Technologies Cooperative Research Centre (DET CRC) and underwent its first extensive, field drilling trials in late February – early March 20 km west Port Augusta.
The trial site was adjacent to a hole previously drilled by conventional (diamond) drilling methods and provided a typical example of the thick cover sequence of the Olympic Iron-Oxide-Copper-Gold (IOCG) Province of South Australia.
Coiled tubing drilling differs from conventional drilling in that the drill string is a continuous, malleable steel coil, as opposed to being comprised of individual steel rods that must be connected and disconnected.
The RoXplorer® rig is a hybrid rig and first drilled, cased with steel pipe and cemented the top ~30 m of the hole. The main hole was then drilled through the cement and into open formation with a downhole hammer and percussion bit powered by a downhole motor. The rig drilled 367 metres in four successive 12-hour shifts, for an average of ~92 metres per shift and at an average penetration rate when drilling of ~15 metres per hour. This compares with around 25 metres per shift at an average penetration rate when drilling of ~3 metres per hour diamond drilling in the adjacent hole.
The hole was terminated at just over 400 metres depth having intersected the target basalt. The cuttings recovered were representative of the geology intersected in the adjacent conventional (diamond) hole.
DET CRC CEO Richard Hillis said the performance of the RoXplorer® Rig and CT drilling ‘system’ was outstanding.
“It is a revelation to watch rapid drilling with no rotation, no-one near the drill string, no rod handling and no fluids on the surface. When going well it is wonderfully dull. When tripping in and out of the hole it is wonderfully quick. Not many people see the start of a revolution in an industry and I was lucky enough to see one on the Eyre Peninsula,” he said. The RoXplorer® Rig weighs only 15 tonnes and can be easily road transported without the need for special permits. As well as being fast and cheap, it offers a substantial improvement in safety because individual rods do not need to be manually handled (moved or connected). The system also offers environmental benefits because drilling fluids are fully recycled using an above-ground AMC Solids Removal Unit (filters and centrifuges) and no sump is dug.
The successful trials represent the culmination of an ~$20M research project by the Deep Exploration Technologies Cooperative Research Centre (DET CRC) to develop a next generation drill rig for greenfields mineral exploration that can drill at a cost of $50/metre to a depth of 500 metres.
DET CRC acknowledges the outstanding team of drillers, assistants, technicians, scientists and engineers from Boart Longyear, CSIRO, Curtin University, DET CRC, the Geological Survey of South Australia, Imdex, Omnilogix and the University of South Australia that undertook the trails and also acknowledges the significant permitting, logistical, safety and geological expertise provided by the Geological Survey of South Australia in support of the trial.
A final field trial is expected to be undertaken around the middle of the year before the technology is offered to DET CRC partners for licencing. The timing of commercial release of the RoXplorer® Rig will be subject to the licencing process and its commercialisation by the licensor.
DET CRC was established in 2010 under the Australian Government’s CRC Program to develop technologies to discover new mineral deposits at depth beneath barren rock cover.
A video on these trials can be viewed here.