The people, science and technology behind discovery

Redefining the search space for minerals

by Dan Zlotnikov on June 4, 2012 expertise

The Earth Explorer team recently viewed a presentation by Campbell McCuaig, Professor and Director at Australia’s Centre for Exploration Targeting (CET), on the challenges facing today’s exploration companies – and, by extension, the mining industry as a whole. McCuaig and other colleagues have told the same troubling story many times before. The presentation begins with the certainty that: The world’s mining industry is facing a worsening resource gap, and unless industry leaders take steps now, the industry’s future is under threat.

The reasons for concern are plain: The amount being extracted has outstripped new discoveries at the same time as demand for commodities is predicted to keep growing. Addressing the shortfall is going to require significant changes in the way the industry operates – and according to McCuaig, these changes have been slow in coming.

Depletion of the traditional search space

The need for new finds is undeniable: McCuaig pointed out that copper demand for 2006-2030 is projected to exceed the sum total of all copper produced in human history up to that point. The situation is generally similar in other commodities, he said.

An underlying cause, McCuaig explained, is the ongoing depletion of the industry’s traditional search space.

“Mankind, over thousands of years, has become pretty good at finding an ore body if it sticks out of the ground,” he said. The largest deposits nearest to the surface are easiest to discover, meaning the trend has been one of huge returns for the first explorers in an area and a steady decline in the value of subsequent, brownfields, discoveries.

McCuaig added that as an area gets mined out, new discoveries aren’t just smaller and lower in quality – they’re also more costly to find in the first place: In the 1960s, $1 of exploration investment returned an average of $105 in discovered gold. By the 2000s, that $1 only averaged an $11 return – despite gold prices rising from $400 to $900/oz. The same loss of exploration effectiveness is seen across all metals.

Despite the rising cost and diminishing return, the trend has been in favour of brownfields projects, at the expense of greenfields funding. At a success rate of below 1%, greenfields projects are much riskier investments than brownfields, causing investors to shy away. McCuaig pointed to this brownfields bias at the expense of greenfields exploration as one of the major reasons for the industry’s current difficulties. He also pointed out that rising commodity prices alone are not a panacea for bridging the resource gap by bringing on lower quality marginal resources – such projects are continually challenged.

Looking deeper undercover

So what can the industry do to address the shortfall? CET’s proposed solution, and research focus, is redefining the search space: looking deeper undercover.

The problem with this is cost: Not only will a discovery require greater outlay, you will have to pay more to even make the attempt. This is a major challenge, said McCuaig, but not an insurmountable one: Just look at how the Gulf of Mexico changed in the last 50 years.

“If  you talk to oil people, they didn’t even believe that there were reasonable deposits deep in the basin,” he said.  “So there was a conceptual leap, from ‘why even bother to look there’ to ‘how are we going to visualize it?’”Today, the Gulf holds some of the largest offshore oil fields in existence.

McCuaig said the mining industry is poised at the same crossroads as the oil industry was 30 years ago. Today’s high commodity prices provide incentive for investment in innovation. It’s this innovation that holds the key to bringing down the cost of making new, deeper, discoveries and securing future resource supplies.

Exploration under cover will be in areas blind to many of the industries standard detection technologies. While  improved sensing technologies will allow us to look deeper, the added cost means these technologies must be deployed more selectively. The challenge, then, is identifying worthy targets for in-depth exploration, and doing so at a regional scale. McCuaig’s presentation described three approaches: An integrated 3D model using geophysics data (seismic, gravity, aeromagnetic), stratigraphic and structural mapping was analysed by a human expert-driven mineral systems approach, a conceptual computer-driven approach and an empirical computer-calculated correlation between predictor maps and known gold showings.

While none of the approaches eliminate uncertainty, the combination of all three allows for better, more accurate targeting, says McCuaig. Of course, there is plenty of room to further refine these techniques – or develop entirely new ones.

One organization working toward that goal is the CET itself: Established in 2005 as a partnership between the Government of Western Australia, the University of Western Australia, Curtin University, and members of the mineral exploration industry, the CET conducts international research and applied projects aimed at developing better exploration targeting models and new technology packages for predicting deposits. The Centre has highlighted greenfields-related research as a focus, aiding current and future industry efforts to look deeper.

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