The South could rival the North I went through my South Zone 3D-IP data review that I posted before start of the drilling campaign. There’s been a wealth of data generated since then and Oroco’s website continues to update features on their 3D model highlighting the various data.
The initial DCIP survey measured a very significant south zone of high-chargeability. It was described in their January 2021 press release as, “Results show a chargeability-high and resistivity-low response spanning 1,000 m wide by 1,200 m long in horizontal plan view that correlates well with the 10 widely spaced historical drill holes...The responses define a wedge 200 to 400 m thick at the western limit, increasing to 600 m on the surveyed area’s eastern fringe. The responses are open at depth and to the east.”
A second DCIP survey was carried out to survey areas of the property even further east. The “Oroco Presentation Deck December 2022” from their website includes a nice 3D model of the survey results, identifying areas with chargeability > 15.8 mV/V. You can see that it extends well past the mountain in the South Zone and into areas further east that have never been drilled. Look at the surface topography with areas represented in bright red splotches along the eastern slope of the mountain. This highly-charged geology is at surface.
High chargeability from a DCIP survey does not necessarily guarantee high copper content in the ore body. The proof is in assay results from drilling, and that’s what is required in order to demonstrate value. The recent south zone assay results were however very good news.
The “Santo Tomas Drilling Feb 2, 2023 Update” 3D model viewer includes numerous cross sections that you can overlay with both historical and current drilling program results. Select the following two cross sections from the menu options and look for drill hole S019 (Hint: The one drill hole in blue color).
XSECTION S2975142N
SZ Plate 38
Results for S019 are pending. I am keenly interested in seeing these assay results because it is placed further into a highly charged zone where nearby historical drilling delivered measured and indicated resource.
Both the historical and more recent South Zone drilling resulted in measured good grades over an elevation range of 400 m – 600 m. There is some variability with surface topography and ore deposit thickness, but generally speaking, this appears to be the range where good grades have been measured thus far in the South Zone.
Oroco’s June 2021 3D DCIP Geophysical Survey technical disclosure included 400 m and 600 m elevation plan views of chargeability and resistivity. This shows very favorable DCIP survey results extending to the southeast over a very large area. The South Zone deposit could potentially cover a greater area than the North Zone deposit and at shallow depth.
In my previous post I mentioned historical drill holes STD-36 and STD-50. A review of tables 7 and 8 in the April 21, 2020 Santo Tomas Technical report reveals that these two holes bottomed out at grades of 0.49% Cu and 0.44% Cu respectively. This means that the grade extends to greater depths than those two holes were drilled back in the day.
Cheers.