New high-grade lithium spodumene intersections from Core Exploration’s (ASX: CXO) Finniss lithium project have shown potential to expand the project’s existing substantial resources.
Assays from drilling at the Sandras and Lees prospects, near Darwin in the Northern Territory, have confirmed lithium mineralisation is widespread within the project lease and may well contribute to an increase in the project’s value and resource potential.
The current global mineral resource for Finniss is 4.3 million tonnes at 1.4% lithium oxide and is expected to grow further when new resource estimates are announced at both prospects.
Best result from recent drilling at Sandras was 24 metres at 1.02% lithium oxide from 177m, including 2m at 2.04% lithium oxide from 182m.
While the deeper part of the prospect has been “incompletely tested below 160m vertical”, Core said it has collected sufficient data to commence definition of a maiden resource estimate for Sandras this month.
At Lees, the drilling of eight reverse circulation holes helped improve Core’s understanding of the geology and identified a down-dip continuation of the northern-most pegmatite.
The prospect returned a best result of 11m at 1.66% lithium oxide from 122m, including 8m at 1.56% lithium oxide from 117m.
Managing director Stephen Biggins said Lees has the capacity to deliver a large deposit of stacked pegmatites with shallow dips.
“Drilling at Lees has shown there are more pegmatite sheets present than [we] first thought,” he said.
“Five sheets identified in recent drilling may have substantial spatial consistency and extend beyond our current drilling area.”
Core also drilled four holes at the nearby Booths prospect, targeting down-dip potential indicated by previous drilling.
The holes encountered pegmatites up to 10m thick but were mineralised only over narrow intervals.
Best results included 6m at 1.03% lithium oxide from 154m; and a notable 5m at 0.95% lithium oxide from 113m situated within a narrow 7m-wide pegmatite and drilled along strike to the northwest.
“The Booths pegmatite [has been] interpreted to persist in that north-westerly direction and potentially links up under cover with the Lees prospect, which has the same orientation and similar pegmatite geometry,” Mr Biggins said.
Mineral resource growth
Core’s flagship Finniss project comprises over 500 square kilometres of tenements within the Bynoe pegmatite field.
To date, the company has confirmed high-grade resources at the Grants deposit and is actively exploring the highly-prospective BP33 target, both of which it says are “integral components” of Finniss.
Grants currently has a resource estimate of 2.89Mt at 1.5% lithium oxide and is considered one of the highest-grade spodumene resources in Australia.
While a number of lithium-rich pegmatites have also been identified at Sandras, Lees and Booths, Core expects its schedule of ongoing exploration will locate new occurrences for further evaluation.
The exploration schedule will include geological and auger mapping, plus drilling and will continue through Darwin’s wet season to month-end.
Regional drilling in the south (within EL30012 and southern EL29698) is currently testing several prospects including Talmina West, Talmina 3, Talmina 9, Sabine, Saffums 4, Saffums 2, Fold, Hungry, Chiastolite, Turners, Ah Hoy and Rocky Ridge.
Exploration is also underway in the north (in EL30015 and northern EL29698) and includes Hang Gong, Carlton, Rubicks, BP2, BP6 and Roses.
“Based on the strength of high-grade intersections from several [new] prospects, [we] expect to substantially increase the mineral resource base for Finniss ahead of first mining and production,” Mr Biggins said.
Definitive feasibility study
Meanwhile, Core continues to work on a definitive feasibility study (DFS) for Finniss, which supports the start-up of a lithium mining and processing operation within the next 12 months.
The study will build on strong financial outcomes highlighted in the project’s pre-feasibility study released in June and is likely to consider substantially-expanded resources, a longer mine life, optimised recoveries and increased grade of product.
Commencement of mining and construction at Finniss has been targeted for mid-2019 and first production of high-quality spodumene concentrate in late 2019.
The DFS is due for completion before year-end.
At mid-afternoon trade, Core Exploration shares were steady at $0.047.