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OreVision and VOXI combine to detect gold targets in the Abitibi

by Virginia Heffernan on July 12, 2018 APPLIED

[Click to enlarge]

Location map of Cartier Resources’ Benoist project northeast of Val d’Or, Quebec.

Abitibi team members setting up the IPower3D IP system. The system allows exploration beneath thick, conductive cover that would normally be impenetrable to IP.

Abitibi team members setting up the IPower3D IP system. The system allows exploration beneath thick, conductive cover that would normally be impenetrable to IP.

[Click to enlarge]

An OreVision survey was completed on a 40 line-km grid that covers a two by three kilometre area of altered and gold-mineralized rhyolitic lavas to detect new zones on the Benoist property to depths of up to 450 metres.

Abitibi Geophysics was able to confirm evidence of additional gold deposits on the Benoist project northeast of Val d’Or, Quebec by inverting IP data from its OreVision system in Geosoft’s VOXI Earth Modelling software.

Cartier Resources had been looking for a way to find extensions of the gold-rich Pusticamica VMS deposit on the Benoist project, but was reluctant to incur the expense of an IP survey without some proof that it would work. Abitibi Geophysics suggested testing to confirm if OreVision, which facilitates exploration beneath thick conductive cover, could identify viable targets at depth.

Abitibi launched OreVision in 2014. The IP technology allows Abitibi to read a large number of dipole spacings rapidly, revealing targets at four times the depth of conventional IP, or up to 500 metres, without compromising near-surface lateral resolution.

The Pusticamica deposit lies along a mineralized corridor stretching between the Langlois and Bachelor gold mines in northwestern Quebec. More than two decades ago, Minnova calculated a mineral resource of about half a million tonnes grading 5.5 gpt gold, 12.1 gpt silver and 0.27 % copper to a depth of 300 metres below surface. The favourable host rocks – rhyolite lavas – extend along strike and at depth.

Cartier acquired a 100% interest in the Benoist property, consisting of 98 mining claims, in July 2013. Subsequent drilling confirmed the continuity of Pusticamica and the potential for additional mineralization at depths of 450-700 metres, likely offset by a fault. Presented with this potential, Abitibi suggested a four-step program to find new targets for drilling.

First, the consultants took advantage of the availability of core samples from Pusticamica to confirm the physical properties of the deposit. They found that even where the VMS mineralization was semi-massive, IP would be more effective than EM as a way to generate targets because Pusticamica is less resistive and much more polarizable than the surrounding host rocks and because the pipe-like shape of the deposit is not favorable for EM techniques.

Next, Abitibi ran a field test over the down plunge extent of Pusticamica to see how the deposit maps at depth and to fine-tune the parameters for a broader survey. The results confirmed that Pusticamica responds well to IP and that OreVision could detect other mineralized clusters at depth, says Abitibi geophysicist Catherine Phaneuf.

Finally, the company completed an OreVision survey on a 40 line-km grid that covers a two by three kilometre area of altered and gold-mineralized rhyolitic lavas to detect new zones on the Benoist property to depths of up to 450 metres.

Abitibi used VOXI to build a drill hole constrained inversion of the survey results. “Using the constrained inversion, we were able to build a more accurate model and confirm the presence of a second mineralized zone south of Pusticamica,” says Phaneuf. “On the other hand, the unconstrained inversion resulted in a big blob which included the known deposit shifted a little to the south. That was an indication of a possible second anomaly but we could not be certain.”

Cartier has proposed a 13,000-metre drill program to test 16 targets generated by OreVision, eight of which have a similar geophysical signature to Pusticamica. Although the company is currently focused on testing the depth and lateral extensions of numerous gold zones at the historic Chimo mine southeast of Val d’Or, it is looking for a partner to share in the cost of a winter drilling campaign at Benoist.


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