NEW drill rig technology with the potential to drastically cut exploration costs has undergone successful field trials in outback South Australia.
The coiled tubing drill rig RoXplorer was developed by the Deep Exploration Technologies Cooperative Research Centre (DET CRC) in South Australia and underwent its first extensive, field drilling trials in late February and early March.
The trial site, 20km west Port Augusta, 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 machine uses a continuous, malleable steel coil as its drill string instead of individual rods that need to be connected and disconnected.
This not only helps make the process fast and cheap but also offers a substantial improvement in safety because individual rods do not need to be manually handled.
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,” he said.
“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.”
The RoXplorer is a hybrid rig and first drilled, cased with steel pipe and cemented the top 30m 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 compared with about 25 metres per shift at an average penetration rate when drilling of 3 metres per hour diamond drilling in the adjacent hole.
The RoXplorer Rig and CT drilling 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.
It weighs about 15 tonnes and can be easily transported without the need for special permits.
The project was a collaborative effort that included help from Boart Longyear, CSIRO, Curtin University, the Geological Survey of South Australia, Imdex, Omnilogix and the University of South Australia.
A final field trial is expected for the middle of the year before the technology is offered to DET CRC partners for licensing.
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.
Last year it developed the Wireless Sub, which used Bluetooth sensors to deliver precise drill rig data in real-time.
The sub enables drillers to replicate the highest performing parameters in any drilling program.
The Wireless Sub was the third major technology licensed by DET CRC, following the AutoSonde for downhole determination of rock properties and the Lab-at-Rig for surface determination of geochemistry and mineralogy.
South Australia is a globally important producer of copper, uranium and zircon.
The state also produces iron ore, zinc, lead, silver, industrial minerals (including salt, silica sand and gypsum) and extractive materials (including dimension stone and opal).