THE KALAHARI SUTURE ZONE PROJECT (“KSZ”)
Kavango’s main focus in the southwest of Botswana is the north-south trending 450km x 50km magnetic anomaly known as the Kalahari Suture Zone (KSZ).
Analysis of previously drilled core suggests that the magnetic anomaly is due to mafic intrusions, many of which are considered to be feeder zones to the vast basalt lava flows which once covered much of southern Africa. These intrusions display distinct similarities to the feeder zones that host the giant Norilsk deposits in Siberia. The project area covers about two thirds of the KSZ as well as unexplained magnetic anomalies on its eastern flank.
Two helicopter-borne electromagnetic surveys covering a total of 4,070 line-kms over the northern part of the KSZ near the small town of Hukuntsi were completed in September 2018 (Phase 1) and February 2019 (Phase 2) by Geotech from Canada and SkyTEM from Denmark, respectively.
SkyTEM’s innovative new generation 312 HP (High Power) technology achieved exceptional depth of investigation (average 400m) beneath the Kalahari sand cover and Karoo sediments due to the high moment (HM) mode with high current and low base frequency of 12.5 Hz. This system has only been on the market since 2017 and therefore represents a major advance in AEM systems.
Aarhus Geophysics, Kavango’s independent geophysical consultant, has produced detailed 3D electromagnetic and magnetic models of the area flown by SkyTEM. This includes interpreted lithological units; magnetic susceptibility models and conductive targets. The model identifies conductors closely associated with gabbroic intrusives and faults. The modelling allows Kavango to view each line flown as a vertical section with depth penetration down to over 700m in some cases. It also provides for horizontal “slicing” at any depth. This enables Kavango’s geologists to move from line to line, at any depth, to view the conductive targets and their associated host lithologies.
Two example cross sections are shown below. The elevation above sea level is shown on the left axis at approx. 1,100m above sea level, and the bottom of the section is approx. 750m above sea level (and importantly beneath the Kalahari sand and Karoo sediment cover). The gabbro intrusive rocks are clearly visible penetrating into the Karoo sediments.
THE DITAU CAMP PROJECT (“DITAU”)
The Ditau prospecting licence (PL169) covers 469km2 and is the most advanced of Kavango’s prospects. The Ditau prospect is a 7km x 5km magnetic and gravity anomaly (see the “Follow-up” grid on the map) with significant zinc-in-soils anomalies. Geochemical soil sampling and geophysics (magnetic and gravity surveys, as well as a ground based geophysics technique known as Controlled Source Audio frequency Magneto Tellurics (CSAMT), have identified a number of large conductive anomalies at depth.
Massive sulphide (base metal) deposits can be detected by CSAMT deep beneath the surface because they conduct electricity easily. The shape, orientation and depth of the conductors determines if the conductor should be drilled, particularly if the conductor coincides with zinc-in-soil (surface) anomalies.
In Q1 2019, Kavango drilled two holes (core).
Both holes encountered intense alteration and deformation of the Karoo age rocks, which lie above a mafic intrusive (gabbro), which is almost certainly the source of the magnetic and gravity anomaly.
The alteration in the Karoo sediments appears to be in excess of 300m thick, whilst the alteration penetrates into the gabbro for at least another 75m. Iron and copper sulphide mineralisation is present throughout the altered Karoo sediments and the gabbro. Indicative cobalt mineralisation has been identified in both holes (portable XRF analyses).
The core from both holes has been cut and sampled in Botswana and has been sent for assay and analysis at a laboratory in Australia.
THE KAVANGO COPPER PROJECT (“KCP”)
This project involves the exploration of an area close to the NW Botswana border with Namibia and covers 3 licences totalling 694km2.
To date geophysics, soil sampling and drilling has been carried out and over $1.5m spent on the project to date.