Smarter use of big data, geophysics, and cloud computing can help boost discovery rates
By Virginia Heffernan | December 11, 2013
Deposits have become harder to find in recent decades, but that may change with technological advances that are making it easier to discover, integrate and model big data; and the rise of cloud computing.
In an interview with Earth Explorer, Rio Tinto exploration executive Amanda Butt shared her views on these and other trends that are making it easier to find subsurface mineral deposits.
“In a lot of cases, we have the data but we haven’t got the most out of it because of time constraints and our ability to find or ‘discover’ this data,” Butt tells Earth Explorer. “Now that we can do things more quickly and efficiently, we can get more effective information out of the data.”
Her insights follow from a keynote presentation by Steve McIntosh, the company’s exploration chief, at this year’s ASEG-PESA International Geophysical Conference in Melbourne, Australia.
Unlike in the past, when close-to-surface discoveries were the norm, the average discovery today is hundreds of metres deep, and that makes geophysics an essential exploration tool. Examples where geophysics play a role in discovery include Rio Tinto’s Diavik diamond mine in northern Canada and, more recently, the Granja copper project in Peru.
Rio Tinto believes that geophysics will become an even more important discovery tool in the future with better collection, storage and processing of petrophysical data. Says Butt: “Geophysicists could do their jobs much more efficiently if they had access to quality petrophysical data, but it’s not as routinely collected or as well-organized as geochemical data tends to be.”
One way to cut down on the amount of time and effort required to turn petrophysical and other data into a reliable visualization of the subsurface is to use 3D inversion models.
The use of 3D inversion provides a valuable snapshot of the most likely distribution of physical properties under the surface. But until recently the technique was limited by computing power and the need for highly specialized knowledge. Inversions could take weeks to complete and introducing physical constraints was problematic.
The rise of cloud computing and advancements in the technology have made the technique much quicker and far more accessible.
At the geophysical conference in Melbourne, McIntosh referenced two separate techniques that accelerate the inversion process: AMIRA International’s P1022 and Geosoft’s VOXI Earth Modelling. The former, led by Peter Fullagar of Fullagar Geophysics Pty. Ltd., converts EM data into magnetic “moments” before inversion whereas Geosoft’s solution is to harness the computing power of the cloud for inversion.
“A lot of EM data has been collected, but historically it has been quite difficult and time-consuming to invert it, try to turn it into a geological model, or constrain it in various ways so that the inversion makes sense considering what we know about the geology,” says Butt. “Ideally, you’d run a number of inversions to test various scenarios, and now we have the ability to do that quickly.”
Rio Tinto has invested in the Geosoft VOXI suite of inversion tools and is encouraging its geophysicists to use 3D inversion on a routine basis.
Eliminating the noise associated with geophysical exploration techniques is an important component of the company’s in house efforts. “In the future we need to improve on the techniques that we already have to eliminate noise and make them much more accurate so that we can be confident that what we are mapping is the geology and not instrument noise,” said Butt.
Deposits may have become harder to find in recent decades, but by eliminating instrument noise, making 3D inversion an integral part of the exploration process and harnessing the unprecedented computing power of the cloud, Rio Tinto aims to see what is currently hidden.
See the original story published on Earth Explorer.