Core Exploration advancing its NT lithium projects toward drilling
6 minute read
With lithium now the hottest commodity in the world, several ASX listed juniors have jumped at the chance to make their mark in this global revolution. Core Exploration was the first ASX-listed junior to highlight the lithium potential of the pegmatites in the Northern Territory in 2016; Finfeed speaks with Stephen Biggins about Core Exploration’s Finniss Lithium Project.
FF: You have recently released rock chip results from lithium sampling at your Finniss Project in the Northern Territory, why have you started there and are you pleased with what you’re seeing so far?
SB: We’ve been operating in the NT now since late 2012, and were greatly aware of the lithium potential in the NT within a number of lithium rich pegmatite fields, so I guess you could say we were blessed with an early mover advantage here. With the strong increase in the price of lithium carbonate in late 2015, we started moving quickly to identify a number of priority areas we’d like to put our foot on.
We’ve now been able to put together a dominant land position across several pegmatite fields relatively quickly, and cost effectively, covering over 2,500 km2 in total.
In early February we boosted our lithium portfolio with the addition of the Finniss Project, which contains the largest historically producing tin and tantalum mine in the NT, and a further 25 smaller pegmatite mines. This is where we’ve started our evaluation sampling and exploration work.
FF: why is tin and tantalum so important?
SB: Tin and tantalum are well known to be pathfinders for lithium mineralisation, so for us, starting work at the NT’s largest historical tin-tantalum pegmatite mine seemed like a great place to start rock chipping.
We’ve undertaken our first sampling programme around the Mount Finniss mine initially to assist us to vector into priority areas for drilling next quarter. We’ve got the first results back, and have more to follow in the next few weeks.
We feel however, that the first results have largely been misinterpreted by the market. Internally, we’re certainly very pleased to be seeing evidence of spodumene and highly elevated lithium values in the Finniss Project. The existence of spodumene is a very important factor that greatly enhances our chances of discovering economic grades of lithium.
FF: What do you think is the key takeaway from this first sampling?
SB: The key takeaway from this is that lithium assays up to 7,589ppm (0.8%) Li2O were recorded in Core’s first rock chip results and all of the samples from Mt Finniss Mine averaged above 1000ppm lithium, indicating that the Mt Finniss pegmatite system is highly enriched in lithium.
High lithium pegmatites were predicted conceptually by Core based on our research, but to get close to economic grades of lithium in our first test sampling from the first pegmatite we tested confirms our early strategy.
It’s also important to understand the impact of weathering on the surface and how that degrades the lithium exposed at surface over time.
FF: Can you elaborate on the impact of the weathering and surface?
SB: As you can imagine, with the surface being exposed to tropical high moisture soils over a long period of time, the mineralisation on the surface is not always going to be representative of the grades at depth, and this is typically the case in the NT.
Much of the pegmatite material available to us for surface sampling and also the mined material from the shallow mine is clay rich and weathered, so making an observational call on mineralogy and grade is difficult. Spodumene readily weathers to clay, so we are of the view that this weathering has resulted in lower grade of lithium at surface than would be present at depth.
Analysis of NTGS geoscientific data from multiple pegmatites throughout the Bynoe Field suggest that the average lithium assays in RC drilling (only 46 previous samples) in the Bynoe field are 3 to 4 times higher than lithium in surface samples (264 samples) – so it is reasonable to expect the lithium grades should be higher at depth when we start drilling.
FF: As you touch on above, these assay results are only the first round or rock chips from a much larger programme. When can we expect to see the next round of results?
SB: The market can expect to see a regular flow of updates and results from Core over the weeks ahead.
We’ve released some early results from the Mount Finniss Mine area, but we have a lot more to follow from further testing, as well as results from the broader Finniss Project area which has another 25 historical pegmatite mining areas within it and we expect to find more.
FF: Why did you choose to explore for Lithium in the Northern Territory?
With over 3 years of experience exploring in the region, we had a good head start when it came to securing a dominant land position that is fertile for the discovery of lithium.
There’s a rich 100 year tin-tantalum mining history in the NT from pegmatites, in particular in the Bynoe pegmatite field, and we saw many analogies with the world-class Greenbushes Lithium Project in WA, which is one the world’s largest spodumene deposits.
The Northern Territory Geological survey has identified over 25 historic pegmatite mines within the Finniss Project area and many other pegmatites not mined for tin and tantalum that have potential for lithium mineralisation.
We’ve also targeted our ground in the NT given the substantial infrastructure advantages available. The Finniss Project is close to grid power, close to gas and rail infrastructure, and within easy trucking distance by sealed road to Darwin Port.
Exploration for lithium in the NT is still in its infancy, however as with Greenbushes, before economic lithium was recognised, Bynoe also has a 100 year history of tin and tantalum mining.
Our core skills are being able to apply a systematic approach to explore for lithium in a meaningful way for the first time in this region.
FF: What news can we expect to see from Core in the next couple of months?
You’ll soon start to see updates from our work on other pegmatites within the Finniss Project and also more assay results from targeted sampling undertaken at Mt Finniss Mine pegmatite and the Finniss Project.
In addition, we expect to commence our first drilling campaign of high priority pegmatite targets into the Finniss Project in the 3rd quarter.
FF: It seems that drilling will be the key test of the Lithium potential on your acreage. When and where will you start drilling?
That’s right, we are very excited to be getting closer to first drilling, and we’ll watching our neighbours results very closely in the next few weeks to see what we can learn from that, as they undertake first RC drilling of their project in the Bynoe field, which is immediately adjacent to our tenements.
We’ve initially submitted our drilling approval application to test multiple pegmatites within the Finniss Project in stage 1, and expect to be in a position to commence drilling as soon as possible in Q3.
We are also planning to develop and rank pegmatite targets prior to undertaking a first round of drilling of the priority targets at our other lithium projects in the NT later this year.
FF: Is there evidence of lithium at your Anningie and Barrow Creek Projects?
Yes, but we are not as advanced with our work on these projects as we are up in the Bynoe field.
In the Anningie Pegmatite Field, work by previous explorers has recorded the lithium minerals spodumene, elbaite and lepidodite.
Research by the NTGS has also highlighted that the lithium contents of the Barrow Creek source granites and pegmatites are considerably higher than most other granites in the NT
The pegmatites that have been recognised and exploited to date are only the near surface expressions, and there is high potential for larger mineralised lithium ore bodies at depth.
FF: Stephen, thank you for your time.