Speaking at the annual Xploration Technology Symposium in Vancouver in January, Nick Payne, IMDEX global product manager, said more time was being spent to drill less and to find less.
"It is taking us longer to complete drill programmes as holes get deeper and by extension taking us longer to evaluate a discovery," he said in his address. "We are now drilling deeper than ever before; we are looking for deposits that are 500m to 1,000m deep because we have found the shallow deposits."
Payne said that in the past 12 years the cost of drilling had increased without an increase in the metres drilled.
Several factors were responsible, including greater drilling rig safety standards; greater environmental and cultural concerns and limited access to land; increased cost of permits; more requirements for verifying data; and a greater emphasis internally among mining companies for QA/QC standards and data verification. "But overall, the one aspect that hasn't improved since 1958 is that there has been very little technological innovation to improve the amount of metres you can actually drill in your drilling time," Payne said.
"Wireline drilling was introduced in 1958. By the late 1980s, after the introduction of impregnated diamond bits, drill programmes averaged about 30m per shift now they are still about 30m per shift globally. So, we have now looked at how we can drill more in the time we have available."
The issues around exploration costs and technology were raised at a recent WA Mining Club panel discussion. Pilbara Minerals, Perseus, and IMDEX non-executive director Sally-Anne Layman said that "for explorers, the days of the equity markets writing big cheques for blank exploration programmes are probably not going to come back any time soon."
Panellist Liam Twigger, managing director at PCF Capital, said: "In the 1990s for every dollar you spent on exploration you would normally find something.
"Now things have gone below surface and we were still until recently using the old techniques. If you want to get money into exploration you have to change the value proposition.
"There is high-risk capital out there, you just have to show them that when they put a dollar in it's not going to drop to 10 cents inside the first six months."
IMDEX's aim is to drive change through research and development that delivers innovations allowing drilling contractors and mining companies to test more targets, decrease the time it takes to define a resource and improve exploration activity.
It has developed IMDEX COREVIBE, IMDEX MAGHAMMER and IMDEX XTRACTA technologies to optimise the drilling process by increasing drilling speeds, time spent drilling and reducing overall drilling costs.
IMDEX COREVIBE is an energy pulse-assisted drilling method which harnesses water that is being pumped down the drill rod. "It is an attachment to the top of you core barrel which creates a vibration in the core barrel and into the drill bit, delivering a micro-hammering effect and this gives about a 30 per cent increase in productivity in drilling," Payne said. "It increases the penetration rate of your drilling and helps working core blockages through were normally you would have to stop and pull the rod; the vibration helps clear the core blockage."
IMDEX XTRACTA is a retractable core barrel that allows drillers to inspect and/or change the drill bit each time the core is retrieved. "This means there is a production gain because you never have to pull rods to change the bit. It reduces the risk of a hole collapsing and gives the driller chance to be a bit more aggressive and to experiment with drill bit types," said Payne.
IMDEX MAGHAMMER uses a new hybrid drilling technique, which combines rotary diamond drilling with fluid-driven percussive drilling to achieve higher penetration rates compared to conventional coring.
IMDEX XTRACTA will be available in the market by end of 2020 and IMDEX COREVIBE by mid-2020. Field trials are continuing with IMDEX MAGHAMMER.
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