What is the Kalahari Suture Zone project’s potential?
The Kalahari Suture Zone project covers a large portion of a magnetic anomaly in southwest Botswana known as the Kalahari Suture Zone (“KSZ”).
The area was the subject of a government-backed exploration programme back in the 1980s, and yielded encouraging early signs of prospectivity. However, the thick overlying Kalahari cover ultimately proved to be too difficult for exploration and drilling technology of the time to overcome.
Today, Kavango is reassessing the KSZ’s potential using modern day surveying and drilling technology.
We began by consolidating a number of KSZ licences, relogging core from historical drilling, and conducting our own surveying. This led us to the conclusion that there was enough sulphur in the molten magma within the KSZ when it formed to create “metal sulphides”.
These metal sulphides can coalesce to form the massive sulphides responsible for some of the biggest mineral discoveries worldwide. Specifically, the KSZ appears to present a distinctly similar setting to the Norilsk mining centre in Siberia, which alone accounts for 90% of Russia’s nickel, 55% of its copper, and virtually all of its PGMs.
Following this, we drilled two conductors identified by airborne electromagnetic (AEM) surveying. This revealed that two prominent layers of rock exist at the KSZ–the shallower Karoo system and the deeper Proterozoic system. These meet a number of important pre-requisites for the formation of magmatic metal sulphide deposits.
Most importantly, the AEM work suggested the presence of an extensive magma plumbing system featuring vertical “dykes” and horizontal “sills” that can transport molten magma from deep chambers to surface “vents”. Over time, this molten magma can then cool to form what are known as “gabbroic intrusions”.
Geophysical 3D modelling by Mira Geoscience then confirmed significant similarities between the shallow Karoo rocks in a northern area of the KSZ called Hukuntsi, and Norilsk.
The imagery depicts numerous gabbroic sills displaying distinct Norilsk-style “gull wings” of intrusive, solidified magma. These gull wings then link to deeper “keels”, that can be closely connected to magma feeder zones. This specific area is where heavy sulphide liquids containing copper, nickel, and PGEs can gravitate, accumulate, and eventually solidify to form metal sulphides.
How is Kavango exposed to the Kalahari Suture Zone project?
We are the 100% owner of 15 prospecting licences covering 8,323km2 spanning a significant portion of the Kalahari Suture Zone anomaly.
What work has Kavango completed at the Kalahari Suture Zone project so far?
In 2021, we selected four primary target areas containing gabbroic sills in our project area’s northern Hukuntsi region. Then, using TDEM surveying, we identified a number of magnetic anomalies here–the highest priority being “A2” in Target Area A and “B1” in Target Area B.
First of all, we drilled two holes at A2. The first hit Karoo gabbros–our primary target–while the second hit the upper edge of a conductive anomaly in the deeper Proterozoic rock.
This opened up the possibility of the KSZ presenting separate, stacked zones of mineralisation, so we remodelled Target Area A in light of our new findings. In doing so, we identified up to 30kms of distinct, magnetic Proterozoic gabbro with the potential to host stacked mineralisation.
Meanwhile, at Target Area B, we were able to establish a growing bank of evidence that the historical “Great Red Spot” anomaly hosts two separate styles of mineralisation.
In early 2022, we completed drill hole KSZDD002, which had been designed to intersect the B1 conductor over the Great Red Spot. Ultimately, we were able to identify a cluster of EM conductors that conform and correspond to similar clusters at the Talnakh and Kharaelakh massive sulphide orebodies at Norilsk:
- B1 Conductor, which has a conductivity of 14,350 Siemens and is classified as a high priority drill target;
- B3 Conductor, which has a conductivity of 4,350 Siemens and is classified as a priority drill target; and
- B4 Conductor, which also has a conductivity of 4,350 Siemens ad is classified as a priority drill target.
Alongside B1, B3, and B4, the B2 anomaly we first identified as a very large vertically dipping conductor in February 2022 is now estimated to be a weakly conductive geological fault running parallel to a probable dyke identified from the interpretation of ground magnetic data. This fault could host a conduit for intrusive Ni-Cu-PGE rich magma.
Meanwhile, in May 2022, we revealed that initial drilling results and subsequent field exploration and detailed desktop analysis had led us to believe that the Great Red Spot also conforms to an idealised model for a large, deeper Iron Oxide Copper-Gold, or “IOCG”, style system.
IOCG systems can host highly valuable copper, gold and uranium ores, and their large size and relatively simple metallurgy can produce extremely profitable mines. In particular, the Great Red Spot exhibits similar geophysical signatures to the Olympic Dam IOCG ore deposit in Australia–among the largest copper and uranium deposit in the world.
Finally, a Proof-of-Concept Drill Campaign Final Report completed by geologist Richard Hornsey, a leading specialist in nickel exploration, in August 2022 confirmed that our drilling has:
- Provided geochemical proof of magmatic Ni-Cu-PGE mineralising processes (depletion and enrichment) throughout the KSZ, for both the Karoo and Proterozoic (Tshane Complex) intrusions
- Identified previously unrecognised PGE potential in the KSZ South
- Introduced new ore deposit models (Norilsk, Insiswa, Eagle, Tamarack, and Uitkomst), which will allow Kavango to vector towards the right host rocks and upgrade future targeting
- Confirmed Kavango is using appropriate geophysical technologies and data analysis techniques to isolate potential mineral bearing targets in a scalable programme
What are Kavango’s next planned steps at the Kalahari Suture Zone project?
Kavango will conduct final modelling on B1, B3, and B4 ahead of drilling and also complete Controlled Source Audio Magneto Telluric, or “CSAMT”, surveys to elucidate the Great Red Spot’s host rock geology and structural setting.
Elsewhere, following the release of an encouraging conceptual economic viability report in July 2022, we are preparing a future exploration plan for the Great Red Spot’s deeper IOCG target that will include test drilling.
Meanwhile, beyond the Great Red Spot, we will complete extensive TDEM & CSAMT surveying across the wider KSZ North and South areas to expand our inventory of targets. We will also continue to work alongside Tamesis Partners LLP to recruit JV partner/s for our KSZ licences.
Geology of SW Botswana with location of Kavango’s prospecting licences on the N-S trending Kalahari Suture Zone & Ditau.
X-Section – Line 100502 in PL365/2018
X-Section – Line 104301 in PL163/2012
Numerous conductive zone anomalies have now been identified. These are currently being followed up on the ground and detailed geophysics and geochemistry are enabling priority targets to be identified ahead of drilling.
Plan view of Phase 2 AEM survey modelled by Aarhus Geophysics Ltd. The image is a horizontal slice at 240m depth below surface showing EM anomalies. Dots represent single line anomalies whereas linear shapes are over several lines. Each horizontal line is 500m apart.