When you have a large, prospective, property you have to use the best, most cost effective, tools to find what you hope will be a deposit. Tocvan Ventures (TOC:CNX) has been working on its Pilar property in Mexico for a little over two years.
The company had a bit of a head start as there had been some work, including 17,700 meters of drilling, done on the property but Tocvan still had a lot of basic exploration to do. Careful mapping, sampling, geophysics outlined three mineralized zones: Main, North Hill and 4-Trench.
With the preliminary work in hand, Tocvan mobilized reverse circulation drills to get an idea of what the deposit actually looked like. CEO Brodie Sutherland explained, “RC drilling is cost effective and quick. It works well in Mexico. But it leaves some question marks on what the structure and geology are doing”
Reverse circulation drilling produces bags of rock chips. Each bag represents a distance the drill has travelled and by assaying those chips you get an idea of the potential grade of a deposit and a sense of how far down the mineralization extends. It is great for what I would describe as reconnaissance drilling. Not so great if you want to understand structure.
In a March 30, 2022 press release reporting early diamond drilling results, Sutherland stated, “Core drilling continues to demonstrate the continuity and strength of oxide gold-silver mineralization at Pilar. Intersecting another broad low-grade zone with a high-grade core is extremely encouraging as we look to advance our understanding of the Main Zone…”
“A diamond drill gives you an indication of how the mineralization is hosted,” said Sutherland. “The original diamond drilling on the property was not very successful. However, twelve years later there have been advances in recovering core.”
“You really learn a lot from diamond drilling,” said Sutherland. “You can actually see what the mineralized body is hosted in. Is it veins or a large breccia body? You can use the core to begin to build a resource model.”
“We are getting excellent core recovery,” said Sutherland. “With each set of good we are expanding the deposit.”
“We’ve twinned a couple of the RC holes which had returned good grades to better understand those zones,” said Sutherland. “We are seeing good grades in the diamond core reported so far and have several holes on trend that are pending results.”
“The diamond drilling is producing good and very useful results,” said Sutherland. “It is confirming the RC drilling but it is also producing new information. We’re infill drilling along strike and working to figure out the structure of the deposit and the host rock.”
“We’ll have further releases in the next month going to the middle of May,” said Sutherland.
On April 14, Tocvan released the results of a diamond drill hole which twinned an earlier reverse circulation hole. “JES-22-59 returned 116.9-meters at 1.2 g/t Au and 7 g/t Ag, including an impressive 48.1-meters at 2.8 g/t Au and 9 g/t Ag. High-grade gold-silver mineralization was recorded adjacent to a heavily faulted and altered zone returning 10.2-meters at 12.0 g/t Au and 23 g/t Ag, including 4.2-meters at 28.3 g/t Au and 49 g/t Ag.”
Figure 1. Drill core from JES-22-59, returned 116.9m of 1.2 g/t Au and 7 g/t Ag.
In the release Sutherland states, “Once again core drilling has confirmed the significant grade and distribution of gold-silver mineralization at Pilar”, commented Brodie Sutherland, CEO. “This further validates the strength of the shallow mineralized system at Pilar, especially in regard to the significant high-grade mineralization adjacent to controlling structures.”
Because this hole twinned an RC hole the results were not wholly unexpected. However, it is always positive to see any results with greater than 10 grams of gold per ton over an extended interval. The hole made the weekly top ten list for gold intercepts, and was the closest to surface at just 20-meters downhole. Further results are expected on trend from this hole which If successful will have a large impact on future resource estimates
Figure 2. Weekly Top Ten Gold Drill Results. Tocvan reported one of the longest and closest to surface drill holes.
Drilling in Mexico stops in late June. “You really can’t drill safely when it is 50 degrees Celsius,” said Sutherland. “We’ll be analyzing our results, doing metallurgy on the material we’ve recovered and building next season’s drill plan. We want to hit the ground running in September after the summer season.”
“In addition, we will also be doing planning and preliminary work on our El Picacho Gold-Silver property within the Caborca Orogenic Gold Belt,” said Sutherland. “We think it has the potential to be bigger than Pilar.”