Tocvan: Structure is Plumbing

CSE.TOC, Tocvan Ventures, gold, silver, Mexico

Having a piece of highly prospective property is a good start for a junior resource company. Tocvan Resources (TOC.CC), after Mark Smethurst, the company’s COO, looked at over 150 possible properties, found a property with high gold and silver potential at the Pilar Gold Property in the Sonora Gold District in the north-west of Mexico. Better still, there had been over 17,000 meters of drilling done on the property. Short holes over a relatively restricted area on the property.

Looking at the historic results, Smethurst wanted to systematically explore the whole property. Soil samples and rock grab samples were reported in a Press Release June 24, 2020. In that release Tocvan stated that the Pilar property had been identified as a “structurally controlled low-sulphidation epithermal project hosted in Andesite and Rhyolite rocks.” And in that release, a new additional zone of gold-silver mineralization was identified from the high-grade gold and silver surface assay results.

The key thing to understand about epithermal systems is that they are the result of a process where hot, metal-bearing fluids come up towards the surface where they are met by cool surface water and rain. Where these waters mix is called the “boiling zone” resulting from chemical and mechanical reactions. The contained metals flow out of their fluid and are deposited in the various cracks and fissures in the surrounding rock. These cracks and fissures are generically and commonly referred to as structures and act as the plumbing system to carry to metal-mineralized-fluids and also act as the deposit sites.

The thing about epithermal systems is that they always have a “source”. You might see rich veining a couple of kilometres away from what is actually the source for the metals in those veins.

“You can think about it as a tree,” said Smethurst on the phone. “All the branches are veins feeding out from the trunk. The geological structures control the flow from the feeders. And you can have very high-grade near-surface.”

In the June 24, 2020 release, the soil sampling which was reported was essentially on top of the structures Tocvan was looking to identify. “The structure is the plumbing,” said Smethurst. “We have 17,000 meters of drilling in the north east zone of the property with good intercepts and grades, but the fluids had to come from somewhere. We think we may have found the source.”

Tocvan hired two consultants, Marion Iseppi Ph.D. Structural Geologist with SRK Consulting and Jeremy S. Brett, M.Sc., P.Geo., Senior Geophysical Consultant with MPH Consulting, to conduct an initial examination of the data produced from the Pilar property to date. Their preliminary conclusions were material enough that Tocvan put out a press release August 25. “There are several initial findings which include a major significant large structure trending NW-SE with approximate dimensions of 250m x 1000m with vertical extents measured in multiple 100’s metres extending to surface (Figure 1a, 2), and bounded within this main structure corridor are additional structures trending N-S with approximate lengths of 300m (Figure 1a).”

Essentially, the consultants have developed a structural theory for the Pilar property where the mineralization sweeps diagonally across the property from a suspected source in the lower, so far undrilled, section of that property. This suggests a targeting approach for a drilling campaign.

“The thing is that this mineralization is very veiny,” said Smethurst. “You would have to do a careful and strategic approach with the drilling to come up with a 43-101 compliant resource.”

Tocvan is certainly looking for targets to drill in its new East zone, however, this drilling would be as much about identifying controlling structures as it was about “defining a resource”, Tocvan’s immediate drill plans are to target the structures and deeper structures in the “Main Zone” and “North Hill Zone”. With veiny deposits it is often better to bulk sample to gain a more comprehensive understanding of the structures and the grades they may contain.

“We want to drill test the new zones and the anomaly,” said Smethurst. “The new zones have never been drilled before.”

In the release, Tocvan CEO Derek Wood commented ” We are extremely enthusiastic that the work done at every stage of exploration since negotiating the option to acquire up to 100% interest in the Pilar property has exceeded expectations and increased our understanding and the potential of the property both as having near term production capability and now has the potential to host a world-class discovery.

Previous drilling had identified a high-grade system at surface in the Northwest area of the property known as the Main Zone. Upcoming drilling will be focused on expanding areas of known high-grade gold and silver mineralization at surface within areas of previous drilling success and also will now test newly discovered ‘at surface’ zones and will include deeper drilling to test the mineralization within the newly identified IP anomaly.”

The August 25th release was technical. As it should be. Future releases, assuming that the structures are confirmed, are more likely to provide grades and intervals. Bulk samples will indicate the sorts of recoveries Tocvan could expect from a pit mining operation.

Right now, the Pilar property is at the beginning of its story. As work advances Wood and Smethurst will have a better understanding of what is potentially a world class deposit. For investors, identifying a solid story at its beginning is a nearly perfect opportunity to make the significant returns junior resource companies can deliver.

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