Engineers at Curtin University have developed a drill rig that promises mineral exploration prospectors cheaper, easier, safer and more environmentally friendly hard rock drilling.
As Australia's resources sector faces a downturn, the quest is on for faster and cheaper mineral exploration options. One of these is the RoXplorer, which is in its final prototype stages, and is on track for release in mid-2016.
The RoXplorer project is also funded by CSIRO, University of Adelaide, BHP Billiton, Vale and Boart Longyear, and is being developed by Curtin University's Deep Exploration Technologies Cooperative Research Centre.
The aim of the project is to develop and commercialise a hard rock drilling-capable rig using coiled tubing drilling technology. This is the same drilling technology used in Queensland's coal seam gas industry.
The coiled tubing allows for continuous drilling, and removes the need for drilling crews to regularly manually handle steel drill rods, which can be up to six metres in length.
The basis of the RoXplorer is high-speed custom-designed diamond drill bits, and percussive technologies which power through the rock. Additionally, the rig itself is small, lightweight, and designed to have a smaller environmental impact at the drill site. It will be rapidly-deployable for drilling campaigns for hole depths of up to 500 m.
Additionally, unlike typical diamond core drilling rigs which rely on longer solid cores to prove mineral reserves and resources, the new approach uses rock cutting samples collected at the surface, as well as down-hole instrumentation to characterise the rock.
These new improvements means the RoXplorer can offer drilling costs at $50 per metre. Diamond core drilling, on the other hand, can cost around $400 per metre of drilling.
The team are continuously improving the technology. In August 2015, the engineers revealed the latest drill bits for the coiled tubing rig. These new drill bits allowed it to hit a consistent rate of penetration of 500 mm per minute in an abrasive granite block, effectively tripling the previous rate of penetration.
While the researchers say that further development, laboratory experiments and field trials will be needed to determine consistency in other rock types, and to measure the longevity of the drill bits, the high rates of penetration proven by the technology will have positive implications for the future use of coiled tubing drilling for mineral exploration.
Further improvements are on the horizon, with engineers promising real-time downhole and surface-based sensing technology which will work with the coiled tubing rig to improve productivity, and allow real-time assaying.