“The first time Norilsk occurred to us as an exploration model was when we first looked at the historical drill core from the KSZ a few years ago,” says Mike Moles, one of Kavango Resources PLC's (LON:KAV) two principal geologists, whos also a non-executive director.
“What struck us was that some of the gabbros had intruded into coal measures which typically contain large amounts of sulphur.”
What Moles is describing with regard to the core from the Kalahari Suture Zone is of course also a distinguishing feature of the giant copper-nickel-palladium deposits at Norilsk.
“At Norilsk,” says Moles, “gabbro intruded into coal measures and incorporated coal into the molten magma so that the sulphur was able to combine with the nickel, copper and platinum group metals and turn them into a heavy immiscible sulphide liquid. This sulphide liquid pooled in trap zones within the sills, and when these eventually cooled, they became the metal-rich deposits that have been so successfully mined for over a century.”
Was this a pattern that was replicated at the Kalahari Suture Zone? The historic drill core confirmed to Moles and Hillary Gumbo (who co-founded the company) that at least it was a question worth asking.
With that in mind, and with the help of a professor of geology from the University of Leicester, they set up a table of characteristics which were typical of Norilsk style mineralisation – of boxes that needed to be ticked – in order for the hypothesis to continue to hold good.
“Weve got up to box number 12 or 13,” says Moles. “There are one or two more boxes we need to tick, but we havent had any negative results yet.”
The latest tick in the box was found through a complex three-dimensional modelling exercise completed by the company in August, and which continues to highlight similarities between the KSZ and Norilsk.
“I was struck by the similarity in the morphology of the sills from Norilsk and those from the KSZ,” says Moles.
“As the magma comes up and approaches the surface, it spreads out laterally along the weaker sedimentary horizons and is then extruded out on the surface as lava. In sectional view the KSZ sills appear as flat-lying intrusive bodies with a typical gull wing shape in the extremities and a much thicker keel towards the center.
Images of many of the Norilsk sills exhibit strikingly similar morphologies. As the molten magma cools, the heavy immiscible metal sulphide liquid tends to gravitate towards the bottom of the sills. Metals and sulphur will probably be much less abundant in the gull wings, but if you drill into the keels you stand a good chance of finding significant concentrations of massive sulphide accumulations.”
Now that the new 3D model is in place, the next steps will be crucial. Drilling is clearly now looming on the horizon, and the latest Kavango press release mentions that the company will seek to define six potential targets.
On the other hand, drilling in this part of the world is expensive and not something to be undertaken lightly. If there is a Norilsk lookalike at the Kalahari Suture Zone, the main reason why it has not yet been discovered could be that its buried beneath around 70 meters of Kalahari sand.
“We could just go and drill now,” says Moles, “but some of the keels are as much as 500 meters deep, so we are now searching for sills that are at a higher erosion level and are closer to the surface. Drilling is very expensive, so we also want to have a high level of confidence that our drill targets will contain massive sulphide accumulations”
Ahead of any drilling, Kavango is therefore planning to undertake ground based electromagnetic surveys using a special technique developed specifically for Read More – Source