Mining geology and the ‘funerals of paradigms’

Richard Roberts

Top image :
Paul Hodkiewicz, principal of Samarah Solutions, speaks at the 2024 International Mining Geology conference
‘The style of rock characterisation we do today is not going to be enough for tomorrow’

Software and sensors are not yet eating the mining world, but the industry’s appetite for the operational knowledge and insight they bring is clearly growing. That came through loud and clear at the 2024 AusIMM International Mining Geology conference.

Silicon Valley founder and financier Marc Andreessen penned his “why software is eating the world” essay in the Wall Street Journal more than a decade ago.

“Six decades into the computer revolution, four decades since the invention of the microprocessor, and two decades into the rise of the modern Internet, all of the technology required to transform industries through software finally works and can be widely delivered at global scale,” he wrote.

The 13th episode of the International Mining Geology conference series started in Mount Isa back in 1990 was all about rocks and geologists, of course. Or geologists and rocks, as some would have it.

But also a stack of new tech.

Conference chair Daniel Howe of Northern Star Resources said while his traditional geologist tools – markers, paint, compass, pencils and (gasps in the room) hammer – “maybe aren’t relevant” in the mine of the future, they still had a place today.

However, he and other experienced geologists at the event said new technologies were fast demonstrating their value in the field at a time when worldwide supply of new geoscience professionals into the industry was slowing and demand for their skills from mineral explorers and miners was surely going to keep growing.

The industry had to start leveraging more of the new technology to make the most of available human skills and experience.

“Maybe we’re not pushing hard enough into that space, and it is uncomfortable to step in there,” Howe said.

“But I don’t think we have a choice any more.”

Respected industry figure Paul Hodkiewicz, principal of Samarah Solutions, said he didn’t have to dig too deeply into a swag of large and mid-tier mining company reports to find the heavy costs, to companies, their investors and others, of fairly standard gaps in project and mine orebody knowledge.

And also the tremendous value being realised from improvements in orebody understanding, either via more drilling or smarter use of a swathe of new sub-surface scanning and sensing tools, or both.

“Stephen Hawking said the greatest enemy of knowledge is not ignorance it’s the illusion of knowledge,” Hodkiewicz said, and he inserted “orebody” before knowledge in the quote.

“It’s not what we don’t know it’s what we think we know.

“Science is the art of finding patterns in reality.

“That quote applies to geoscience, too.

“We’re constantly trying to fill in the gaps between drill holes or whatever kind of real data we have.”

Hodkiewicz said German physicist Max Planck’s saying about science advancing “one funeral at a time” had literal meaning, but was “also about the funerals of paradigms”.

“I don’t think we have to wait for funerals in geoscience … for new ways of thinking about orebodies [given the] new opportunities we have with all the new data we’re getting.

“Instead of looking at drill holes individually [we can] think of them as long, skinny outcrops. And the workflow should be about mapping between the drill holes.

“That can make a real difference, because you’re looking at the drill holes in context, in a 3D context, and I think that can really change the way you interpret the orebody and take advantage of all this new data.

“We have lots of sensor-enabled mobile equipment in a mine, and in the mill, and they’re all connected and generally communicating with one another in IROCs and operating centres.

“But we have [new] opportunities now with the better geoscience data we’re getting, [particularly] at the resolution and detail that we’re starting to acquire at larger volumes from core scanning and down-hole sensing and drones.

“The opportunity is to link … all the components of this integrated mining system to deliver better orebody knowledge to the customers of the orebody; the mine planners and mining engineers and metallurgists.”

BHP head of geoscience Cam McCuaig said in his keynote address at the conference the mining major was “thinking about innovative datasets to frontload geoscience” and he cited recent exploration work at the deep Oak Dam iron ore-copper-gold (IOCG) project in South Australia and the nearby flagship Olympic Dam copper-uranium-gold mine.

“The style of characterisation we do today is not going to be enough for tomorrow,” McCuaig said.

“It’s still brute-force drilling that we do. We do a lot more with the drilling, which is great. But we’re still doing a lot of brute-force drilling.

“We’re quantifying pencils in space and everything in between is made up.

“We use geological rules and geostatistics, and we’re good at it.

“But we’ve got to go from quantifying pencils in space to volumes of rock and we’ve seen some good examples of that [at the conference]. We had rock seismic at Mount Isa. We saw muon technology.

“The top of the Oak Dam deposit is, at best, 750m under cover, so it’s expensive to drill and it takes a long time to drill.

“But we’ve got to characterise the rock mass.

“So we harnessed the power of seismic. We broke a world record for in-hole optic fibre cable [2.1km] deployment. We shot sparse 3D, changed our whole view on the deposit and actually found extensions to mineralisation, which we didn’t expect.

“We’re in a situation where we want to accelerate development and characterisation of this [deposit] but it’s going to take a long time just by traditional drilling. So we’ve got to think differently.”

Ideon Technologies’ Doug Schouten

Doug Schouten, co-founder and chief technology officer at Canada’s Ideon Technologies, told the conference muon tomography surveys at BHP nickel operations in Western Australia, and at Olympic Dam, had shown the value of the technology in mineral exploration, resource mapping and geotechnical applications. The work demonstrated the relative cost effectiveness of the survey and imaging method and the “very high resolution that’s unsurpassed with other geophysical techniques over very large volumes of rock” (up to 1.5 billion cubic metres at Leinster).

“We use the energy from super nova explosions light years away to image density structures down to a 1km beneath the Earth’s surface,” Schouten said.

“The way to think about this is by analogy to medical analysis where we use X-rays to see inside the human body. Where the X-rays are stopped, where they are not passing through, we can make inferences about bone structure in the human body.

“We can play the same game with cosmic rays coming from space that are being stopped, enabling us to understand something about the density structure in the subsurface.

“This allows us to see inside the Earth and make high-resolution 3D models of 3D density, both from the structural perspective but also mapping density values.”

Schouten said BHP used existing survey and other data to validate the muon tomography imaging results, but they also generated valuable new insight.

At Leinster, multiple phases of work took about six months.

“That is a function of the total deployed detector area,” Schouten said.

“The physical measurable is the muon intensity, which is the number of muons making it through per unit area.

“By deploying additional sensors we can linearly affect the exposure time required. Just like a larger camera sensor, you can leave the shutter open for shorter to acquire similar light.

“Double the number of detectors, half the exposure time.

“The bookends of deployment time [for the muon surveys] are a month up to a year.”

Principal geophysicist at hard-rock seismic specialist HiSeis, Greg Turner also used the medical analogy.

“We don’t do modern surgery without a scan,” he said.

“How much could we save by scanning the rock mass before we actually mine?”

Extensive 2D and 3D seismic survey activity for Glencore over “one of the most highly studied geological rock volumes on the planet”, Mount Isa in north-west Queensland, had also generated fresh insight and understanding, underlining the potential value of non-drilling sub-surface investigation.

“Seismic maps changes in impedance and most different geological units do show variations in acoustic impedance,” Turner said.

“In the Mount Isa region we have largely focused on the copper orebody there, with all the work that was done for Glencore.

“Since 2020 we’ve acquired eight 2D seismic lines covering approximately 90 square kilometres and a 3D seismic survey covering about around Mount Isa.

“Despite all of the investigation that’s happened over the previous century the seismic surveys have provided some new insights into Mount Isa’s copper mineral system.

HiSeis’ Dr Greg Turner

“3D active seismic is the only technique that provides resolutions of tens of metres over tens of cubic kilometres of ground.

“Benefits include the ability to track the continuous 3D location of faults, which gives you improved understanding of mineralisation controls, improved understanding of mineralisation offsets, and importantly improved understanding of where geotechnical hazards are, allowing you to optimise the location of development and stopes and shafts.

“And we get this continuous map of the top of fresh rock.

“The ability to continuously map faults in three dimensions is huge for mining.

“If you know where those faults are then the infrastructure such as shafts, raise bores [and] declines can all be placed optimally. If you’re installing one of these and you unexpectedly intersect faults, it can potentially very quickly add up to tens of millions or even hundreds of millions of dollars.

“Using the 3D seismic we can either avoid those faults or we’ve got their presence planned for and their impact can be minimised.”


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