3-D Geologic Modelling Supports Deep Mineral Exploration
By Chantal Hunter
May 2012
Deep earth imaging is revealing undiscovered mineral and metal deposits and providing a more complete three dimensional picture of the subsurface for mining exploration.
Flin Flon mining camp on the border between Saskatchewan and Manitoba.
Canada is one of the largest mining nations in the world. There are more than 200 active mines in Canada, producing more than 60 minerals and metals.
However, reserves of base metals such as copper, lead, nickel and zinc are declining as a result of the depletion of known deposits. Rates of discovery for new deposits are also declining. New and innovative knowledge and techniques are required in order to discover the untapped mineral deposits that lie far below the earth’s surface.
One of the most promising techniques is 3-D modelling, which integrates seismic, drill hole and geological map data to map the deep geological structures beneath established Canadian mining communities.
Seismic Data Plays Key Role
Vibroseis trucks which produce accoustic waves.
Research on 3-D modeling is being conducted by Natural Resources Canada (NRCan) and its partners under the auspices of the Targeted Geoscience Initiative (TGI). The aim is to provide industry with the next generation of geoscience knowledge for more effective targeting of deeply buried mineral deposits.
To prepare 3-D images, scientists conduct seismic exploration. This involves generating accoustic waves at the surface that travel through the layers of the earth’s crust. At the boundaries between different rock types, some of these waves are reflected back to the surface where they are recorded by arrays of sensitive detectors. Reflections from shallow formations arrive at the surface sooner than reflections from deeper ones. By processing the time delays between the recorded reflections, 3-D images of the geological structure are generated.
Researchers are then able to reconcile these 3-D seismic images with drill log data and geological map units. This allows them to get a clear picture of the rock formations beneath the surface.
Perfecting the Technique
Over a five year period, scientists with NRCan’s Geological Survey of Canada undertook research at the Flin Flon mining camp located on the border between Saskatchewan and Manitoba.
Team members harnessed expertise in geophysics, regional geology, economic and mine geology, geochemistry and geoinformation science. The result was the first 3-D geological model of deep underground rock units and geological structures at the mining camp.
Armed with this new deeper picture, new exploration drill targets can be determined. “The new methodology greatly enhances the ability of exploration companies to focus drilling at greater depths,” says Ernst Schetselaar, a 3-D Geologic Modelling Specialist at NRCan.
New Discoveries
3-D geologic model of the Flin Flon mine horizon (yellow surfaces). The ore lenses (red) have been stacked on top of each other by a set of thrust faults (lilac surfaces).
The 3-D geologic methodology developed at the Flin Flon camp is actively being used by exploration companies in their exploration programs to target drilling sites. As a result, the newly integrated methodology contributed to the recent discovery of 0.35 million tonnes of ore by Hudbay Minerals Inc.
The development of innovative 3-D geological methods at Flin Flon and the successful transfer of this technology is helping to stimulate more effective private-sector resource exploration, reduce exploration risk, and increase exploration success and discovery rates for base metals in Canada.
For more information, visit NRCan’s TGI site.
To read about related articles, see Maps and Mapping.
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