Following successful field trials, an innovative new drill rig that could revitalise Australia’s mining industry is a step closer to commercialisation.
The RoXplorer has excelled in its second major field trial, readying it for licencing and potential commercialisation by the end of 2017. The prototype coiled tubing (CT) drill rig, developed by the Deep Exploration Technologies Cooperative Research Centre (DET CRC), underwent the trial during May and June 2017 in the Murray Basin near Horsham, Victoria.
Unlike its first trial, which took place in consolidated cover rocks near Port Augusta, South Australia, the second trial presented more challenging conditions in unconsolidated cover. “The first trial in the Gawler Craton near Port Augusta demonstrated that hard rocks could be drilled at rates approaching 100m per 12-hour shift, across multiple shifts with excellent sample returns,” explains DET CRC’s CEO, professor Richard Hillis. “This second trial was more challenging and showed that unconsolidated cover overlying a prospective basement, and the underlying basement, could be drilled at similar rates with the same excellent sample returns.
“We don’t believe that the unconsolidated cover at Horsham could have been drilled by the traditional reverse circulation (RC) method, meaning the CT Rig provides the only cost-effective alternative to expensive sonic or mud rotary surface and diamond-tailed holes. This new technology has opened the Gawler Craton, Murray Basin and similar areas of extensive cover to ‘prospecting drilling’, which will enable progressive vectoring towards concealed mineral deposits using multiple, cheap holes in a single drilling campaign, thereby opening the covered mineral exploration search space.
“These results bring us closer to delivering on our goal of developing cheaper, faster and safer methods of exploration, which has the potential to revitalise Australia’s mining industry through the discovery of new mineral deposits hidden under deep rock cover.”
In a further positive for the CT Rig, the results of assays from the first trial near Port Augusta showed a strong match to those from diamond drill core from an adjacent hole. “The match of assays from CT Rig drilling to diamond drill core from an adjacent hole are remarkable,” Hillis says. “Concentrations of major and trace elements closely match those of the diamond drill core, giving no indication of sample bias or contamination.
“It was particularly pleasing that a narrow interval of low grade copper enrichment at 400m depth was faithfully represented in the assay data from the CT cuttings.”
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. It can drill to depths of 500m, and with no rod handling required it removes the major cause of injury in mineral exploration.
The RoXplorer CT Rig is a hybrid rig, designed for coiled tubing drilling but capable of drilling with a top drive and conventional drill rods. It weighs only 15 tonnes (including coiled tubing drill string) and can be easily be road transported without the need for special permits.
The successful trials represent the culmination of a AU$20million research project by DET CRC to develop a next-generation drill rig for greenfields mineral exploration that can drill at a cost of AU$50/m to a depth of 500m.
The technology will be offered to DET CRC partners for licencing shortly. The timing of commercial release of the RoXplorer Rig will be subject to the licencing process and its commercialisation by the licensor.