Santo Tomas Is Bigger Than It Looks!
Last week Oroco Resource released its updated 43 101 report on the Santo Tomas Deposit in Northern Mexico. It used data that was acquired from past operators at a vast discount to what it cost to produce giving Oroco a huge advantage preparing for continued exploration and expanding the current resources at Santo Tomas.
The World has come a long way from where it was when Santo Tomas was first discovered in the late 1960’s. Base and precious metals prices are vastly higher and accessory metals such as molybdenum weren’t even considered back then. These all add up to make Santo Tomas even more attractive.
Exploration techniques and processes have also undergone a massive shift in understanding through decades of study since first discovery. It appears evident that past operators either didn’t have a complete understanding of the deposit or were trying to fit the data into a pre existing model of what they thought Santo Tomas was.
Exall was focussed on proving up a near surface oxide deposit and therefore terminated many holes while still in mineralization. Most of the historic holes are vertical passing into and rarely out of the now understood dipping mineralized zone.
“Collectively, all historical drilling information was biased towards relatively shallow, vertical holes that do not fully test the breadth of the moderately west-dipping Santo Tomás main mineralized zone.”
The new interpretation clearly shows a moderately dipping structurally controlled deposit of about 400 meters thick that was never drilled to properly define its boundaries.
Proposed holes by Oroco now will intersect the deposit at nearly right angles to clearly define the size and orientation of the mineralized zone.
These interpretations extend to the south zone and also across the river to Los Brasiles. 
The volumes of the deposit are quickly becoming very very large since we can trace the structures that control the deposit for nearly 3 kilometres and it is open at both ends crossing the river to the North!
The proposed 3D IP survey will give us a detailed roadmap to just how big Santo Tomas can get. If we can show a continuation of the mineralized zone North of the river at Brasiles for say one kilometre we are at 4 km of strike and say another kilometre to the south where we already know there is proven mineralization our deposit could grow to 5km of strike or more!
This figure is looking at the front edge of the deposit looking west so the main body would be dipping away from us into the page. We can clearly see that it is at least 400 meters thick and in places up to 600 meters thick with good grades throughout and drills not piercing the bottom of the mineralization.
Looking at the drill tables it appears the holes that were drilled close to the footwall, grade increases with depth. Hole 19 ended in .52% mineralization and 27 in .57% Cu with what appears to be another 100 meters or so of projected mineralization before exiting into the footwall. This is very exciting for 2 reasons it could be there is enrichment nearer the footwall or even more exciting there could be enrichment at depth down dip drastically increasing the total pounds of copper contained at Santo Tomas!
Doing some rough calculations on volume we can see just how big it can get. Using a 400m thick vertical dimension by 5km long including Brasiles North of the river by say 600 meters deep we get up to 3 billion tons of mineralization. At a grade of .4% (I think it will be higher) gives a possible 24 billion pounds of copper. Exploration upside is massive!
The data in the recently released report is current only as of the last day of drilling by Exall some quarter century ago. Metals prices have gone up exponentially since then with Gold Silver and Molybdenum being included in economic concentrations since the original work was done. The structure is massive and not represented by the previous work making Santo Tomas much much bigger than it looks right now!
Oroco needs to produce some new drill reports to establish any expansion of the higher grade deposit and secondarily the overall deposit. It will be interesting to see who they partner with for the drilling. Drilling is expensive but the 43-101 does have lots of advice on how to proceed.