This week, I want to talk in a bit more detail about Kavango’s innovative use of Controlled-Source Audio Magnetotellurics, or CSAMT.
We’ve recently released several announcements covering our use of the technology on licence PL082 in the Kalahari Copper Belt. However, these announcements are fairly jargon heavy so I wanted to provide some additional context in today’s newsletter. What we’re developing does look like it is truly ground-breaking and has already attracted some significant external interest.
As far as I’m aware, no one else has ever deployed CSAMT in the way we are in Botswana.
If our approach is as successful as our early progress suggests, it could be an exploration game-changer not just for the KCB, but for Botswana as a whole.
Let me explain…
In the world of oil & gas exploration, there’s a powerful surveying technique known as 3D seismic. It effectively works by visually mapping the structures underlying a target area so oil exploration firms can identify potential trap zones into which oil could have accumulated.
The tech has led to many of the world’s largest hydrocarbon discoveries. But it’s also very expensive. So expensive, in fact, that using it to an adequate equivalent scale in the search for metal mineralisation puts it beyond the budgets of our sector.
With CSAMT, however, we are well on our way to pioneering a new technique that can generate targets almost as effectively as 3D Seismic in the KCB, but at a fraction of the cost.
It “slices” through the earth to pinpoint individual rock layers that could be areas of alteration and mineralisation.
More specifically, sensors are laid out on the ground to pick up two key data points from natural electro-magnetic signals generated beneath the ground:
- Frequency: which tells us the depth a signal is being generated from
- Resistivity: which tells us what could be in the rock making the response
These EM signals are fed into a computer so they can be ranked by frequencies, with resistivities of particular ranges grouped into separate “domains”.
This then creates a geological map like the below that “sketches” out potential rock layers to a particular depth, as you can see in the image below taken from a CSAMT line we ran over the Great Red Spot in the Kalahari Suture Zone:
While these “vertical slices” can’t tell us what kinds of rock each layer contains, they can show us their shape and position.
By comparing the CSAMT “sketch” with other data sets (such as the data taken from a drillhole), we can look for similarities and extrapolate what rocks might be present at different depths.
Not just that, but we can use CSAMT data to look for areas that might be altered or broken up by geological events such as intrusions. Essentially, what we are looking for are the right sort of areas that could have host mineralising events and from this we can use CSAMT to delineate priority targets for drilling.
Optimising for the KCB
Now, like any exploration technology, CSAMT must be properly calibrated to its environment.
After all, whether it’s terrain, sub-surface bodies, temperature, climate, or topography, there are so many factors that will impact its effectiveness. In other words, you can’t just turn up on the day and expect CSAMT to magically work.
This is where Kavango has an edge.
Over the last 12 months, our geophysical experts Jeremy Brett and Hillary Gumbo have optimised how we collect, process, and analyse CSAMT data for the KCB. As we announced last week, this has enabled us to create high definition vertical slices down to an impressive 4,000m.
We’re now testing the accuracy of this imaging in our current drilling programme. While our top priority is to find mineralisation, if we can demonstrate the CSAMT works as we believe it does then this will be a big win for Kavango.
This allows us to look at what our CSAMT lines highlight about different rock layers and see if it matches up with what the core we’re taking from the ground. And perhaps the most telling of all these will be CSAMT Line 4A.
You see, our neighbour Sandfire Resources has allowed us to extend this line beyond PL082’s boundary and on to ground where its Kronos copper deposit is hosted in a “D’Kar/Ngwako Pan contact zone”.
These areas where the “D’Kar” and “Ngwano Pan” rock layers meet represent the primary control of copper/silver mineralisation for the entirety of the KCB.
So, if we can successfully use Line 4A to identify the extension of this contact zone on to our own licence area then, as with 3D seismic, we effectively find ourselves with a way of mapping the location of proven mineralisation trap zones without drilling.
That could be crucial for exploration across our wider KCB licence package, and we’ve already deployed CSAMT equipment to our Mamumo and PL036/PL037 licences. But it also could be a huge development for the wider KCB and any area of Botswana covered by thick Kalahari sands–roughly 70% of the nation.
The opportunity for partnerships is tantalising.
But first, we need to prove CSAMT’s efficacy. With the final interpretations being delivered and drilling well underway, that moment is likely to arrive sooner rather than later.
Next step is to finish interpretation of the Line 4A data and share it with Sandfire. Once everyone is in agreement, we will be able to publish the results in an RNS. We will then all need to wait and see what the drill core has to tell us.
