Riversgold Ltd (ASX:RGL) has confirmed multiple, wide spodumene-rich lithium pegmatites from a reverse circulation (RC) drill program conducted last quarter at the Tambourah Lithium Project in the Pilbara region of Western Australia.
This drilling program comprised 21 RC holes across 2,661 metres at the Bengal Prospect and was part of RGL’s maiden drill program at Tambourah.
The best lithium mineralisation intersection was TMBRC003, a 14-metre downhole intersection, within a pegmatite unit displaying a high-grade spodumene core and lepidolite at its base.
During the program, Riversgold intersected mineralised pegmatite at depth in 16 holes targeted using geological mapping and observation of the occurrence of lepidolite mineralisation at the surface.
In addition, four of the five holes targeted using deep ground penetrating radar (DGPR) to locate pegmatites where no surface expression is evident were successful in intercepting pegmatite with drilling down to 80 metres.
Results from the field programs are expected in the next few weeks and will form the basis for the 2023 drilling and exploration program which is scheduled to commence later this month.
Significant step
Riversgold CEO Julian Ford said: “These drill results are the culmination of our 2022 exploration program at Tambourah and represent a significant step forward to unlocking the lithium potential of our Pilbara tenement package, located close to the globally significant Pilgangoora and Wodgina deposits.
“We have only really started our exploration efforts at Tambourah and receiving the confirmation that we have pegmatites up to 14 metres in width with spodumene lithium mineralisation is critical to us now being able to move the project forward.
“We believe that our 2022 drilling was potentially too close to the granitic source and drilling slightly further to the east, targeting major dilation zones, will provide the consistent widths of mineralisation we are after.
“We expect to publish the results of our extensive geochemical and geophysical results in the coming weeks, which we will use to develop our drill targets for 2023.”
Drill program
Twenty of the 21 drill holes intersected a cumulative total of 143 metres of interpreted lithium-caesium-tantalum (LCT) pegmatite.
The lithium mineralisation intersected is composed of a mix of spodumene and lepidolite, although a more detailed quantitative mineralisation identification program is yet to be completed.
The hypothesis was that it was likely that wider pegmatites with the potential to be spodumene-rich could be present at depth.
Riversgold considers that the exploration drill program was highly successful in proving the hypothesis, with the widest pegmatite width intersecting 17 metres downhole in hole TMBRC011.
RGL’s maiden Tambourah lithium exploration drill program validated that the Bengal pegmatite system is a spodumene-rich LCT system where fresh subsurface pegmatite is significantly broader than the narrow, weathered surface outcrop.
More importantly, the company has confirmed that the dominant mineralisation species is spodumene.
Forward plan
As a result of the encouraging preliminary drill results in the December quarter of 2022, the company extended the DGPR coverage area to the east at Bengal.
A 1,800-sample geochemical program has been completed which has extended to the east into ultramafic greenstones.
Results from these field programs are expected in the next few weeks and will form the basis for the 2023 drilling and exploration program which is scheduled to kick off in late March 2023.