The latest exploration results from the Wardawarra Project of Rumble Resources Ltd (ASX:RTR, OTC:RTRFF) in the Murchison Goldfields region of Western Australia highlight the potential for multiple lithium-bearing pegmatite systems.
These results also reveal the discovery of a partly preserved mafic to ultramafic layered igneous complex highly prospective for nickel, cobalt and PGEs.
Wardawarra Project has seen no historical exploration for lithium and only limited nickel and cobalt investigations in the 1980s. Exploration by Rumble included aircore and slimline reverse circulation (RC) drilling with regional rock-chip sampling.
Revisiting projects
Rumble managing director and CEO Peter Harold said: “Rumble’s primary focus is to progress the potentially world-class Earaheedy Zinc-Lead-Silver Project, however, while we are undertaking the metallurgical test-work on Earaheedy material there is an opportunity to revisit the high-grade gold deposits at the Western Queen Project and lithium at Wardawarra.
“Work by our geologists and previous owners has confirmed the presence of pegmatites and high-grade lithium oxide from rock chip samples. It is also significant that there is a 12-kilometre-long swarm of fertile pegmatite dykes.
"Within that is a 3 kilometre high-fertility zone and that the previous owner, Pancontinental Mining, ranked Wardawarra in their top five lithium/tantalum prospects with a portfolio of projects that included Pilgangoora, Wodgina, Tabba Tabba and Yinnetharra.”
Western Pegmatite Zone and Lithium Creek
Rumble’s exploration has highlighted a prospective 6-kilometre-long trend containing multiple large pegmatites along a granite-ultramafic contact north of the Western Queen Gold Deposit.
The pegmatites here trend to the northwest and are more than 15 metres thick in outcrop with surface exposures of several hundreds of metres across strike, suggesting that the pegmatites may have substantial true thicknesses.
Multiple pegmatites appear to have undergone significant zonation fractionation and many have fractionated quartz cores. Rock chip sampling has returned high-grade assays of up to 3.62% lithium oxide and 433ppm tantalum oxide.
Eastern Pegmatite Swarm and Dunn’s Prospect
Exploration at the project’s Eastern Pegmatite Swarm has confirmed that a 12-kilometre-long swarm of pegmatite dykes are lithium-cesium-tantalum (LCT) fertile with a 3-kilometre zone of high fertility (ie low K/Rb ratios).
The Dunns Prospect is in the southern portion of the zone of highest fertility. Rock chip sampling at Dunns has returned high-grade assays including 4.95% lithium oxide, 4.91% lithium oxide, 4.84% lithium oxide and 4.72% lithium oxide.
The Fence Prospect
The Fence Prospect and the LCT fertile pegmatite field was previously held by Pancontinental Mining Ltd who in 1983 ranked it in their top five lithium-tantalum prospects with a portfolio of projects that included Pilgangoora, Wodgina, Tabba Tabba and Yinnetharra.
Historic shallow alluvial mining at the Fence Prospect was undertaken for tantalite/columbite, but its lithium potential is untested by drilling.
Tantalus Prospect
At Tantalus Prospect, a single traverse of RC drilling has confirmed the potential for a large lithium-bearing pegmatite system under shallow cover. The prospect is a shallow east-dipping weathered pegmatite system hosted in ultramafic rocks and consists of two zones trending north-south over a strike of 600 metres (open). The upper pegmatite (width up to 30 metres) is lithium-bearing.
Airborne magnetics has interpreted up to eight pegmatites within the Yinga Ultramafic Complex that are of similar or larger size compared with Tantalus, that occur under cover. Previous grab sampling has returned up to 2.58% lithium oxide where the lithium-bearing pegmatite is exposed in a historical shallow pit.
Assessing Wardawarra’s lithium potential
Rumble has planned a detailed mapping and geochemical sampling program to vector the best fertility zones within the Western and Eastern Pegmatite prospect areas. This will assist with immediate drill hole targeting.
The company will also review pegmatite intersections in previous Rumble and historic drilling within the Western Queen mining licences (E20/967 and ELA59/2443) for lithium fertility.
Harold added, “Rumble’s next steps in relation to the Wardawarra lithium exploration is to undertake detailed mapping and geochemical sampling program to determine the best fertility zones within the Western and Eastern Pegmatite prospect areas for drill hole targeting, and to review pegmatite intersections in previous Rumble and historic drilling within the Western Queen mining licences for lithium fertility.
“We are lucky to have a number of projects within Rumble covering a suite of commodities and we look forward to updating shareholders on our exploration activities at Western Queen and at Wardawarra.”