In this week’s edition of Bulls N’ Bears Big Hits, we examine some of the notable drill intersections revealed on the ASX, including Wildcat Resources’ run of 67m at 1.9 per cent lithium oxide from its Tabba Tabba project in Western Australia’s Pilbara region.
We also take a close look at other interesting drill hits from last week as reported by Rumble Resources from its Western Queen project in WA and Strickland Metals at its Rogozna project in Serbia.
So, let’s dive in.
Wildcat Resources
Tabba Tabba project – Pilbara region, WA
Hit: 67m at 1.9 per cent lithium oxide from 338m
Wildcat nailed this boomer of a lithium hit, which includes 46m at 2.5 per cent lithium oxide from 338m in its Leia pegmatite that outcrops over a distance of 1km.
It was accompanied by an intercept of record thickness in its Leia pegmatite at 75m estimated true width – albeit, with it running a lower grade of 1.1 per cent lithium oxide from 155m including 49m running 1.4 per cent lithium oxide from 181m.
The richly-mineralised Leia body is one of six distinct pegmatite bodies in the biggest of the company’s multiple tenement groups, which contains most of the Tabba Tabba pegmatites of current interest. That tenement block is centred about 56km south-east of Port Hedland and straddles Wallareenya Road, just 34km north of Pilbara Minerals’ world-class 414 million tonne Pilgangoora lithium project.
Within the block, the impressive Tabba Tabba pegmatite swarm occupies an area measuring about 3.7km long north-east/south-west by about 830m at its widest point, tapering in the south-west to a tram-lined belt of sub-parallel pegmatites only about 330m wide.
While extensive drilling has been undertaken at the project, including more than 105,000m by Wildcat since it acquired it little more than a year ago, most of the exploration focus has been on the Tabba Tabba pegmatite. However, the other five Star Wars-themed Hutt, Leia, Chewy and Luke pegmatites have also felt the bite of the drill bit.
The Leia pegmatite is spodumene-dominant, strikes for more than 2km, is up to 180m wide and averages 1.1 per cent lithium oxide. Drilling at Leia has involved multiple 50m-spaced step-outs along strike and down-dip from known zones of interest and has identified new high-grade lithium zones.
Ongoing drilling at Leia continues to flesh out its extent and management is gradually outlining its massive economic potential, adding to that of the overall Tabba Tabba project.
Historically, Tabba Tabba was one of four significant lithium-caesium-tantalum (LCT) pegmatite projects in WA previously owned by Sons of Gwalia or its subsidiaries. The company’s other projects were Greenbushes, Pilgangoora and Wodgina, which are all now tier-one hard-rock pegmatitic lithium mines, while Tabba Tabba is the last of those project areas to be explored for lithium mineralisation.
During the 1980s, Pilgangoora hosted Greenbushes’ subsidiary Pilgan Mining’s big alluvial plant, which exploited its extensive local tenure area for surficial eluvial, colluvial and alluvial tantalite-columbite and incidental tin. Pilgangoora also served as a base camp from which Pilgan’s exploration parties would sally forth to explore the nearby Tabba Tabba and Lalla Rookh ground and other prospects as far afield as Marble Bar and Wodgina for their alluvial tantalite potential.
The lithium ore mineral spodumene lay all over the ground like spuds in a paddock at Pilgangoora, Tabba Tabba and many other local prospects, but was largely ignored.
We geologists used to go out at night looking for spodumene hand specimens with an ultra-violet (UV) lamp and it occasionally offered the experience of walking over a bed of glowing coals as all the surface spodumene fluoresced a range of colours under the UV. Coupled with the overhead blanket of the Milky Way in the typically clear air and complete absence of light pollution of the remote Pilbara, “spod-spotting” was pretty special and beat spending the evenings in the wet mess.
But going back to Wildcat’s Tabba Tabba venture, diamond drilling is advancing the company’s geotechnical studies on the open-pit wall-rock stability of its proposed mine, ahead of future mine development. The company says its next steps include aggressive exploration for new discoveries further afield within the greater Tabba Tabba project area and undertaking a broad fourier transform infrared (FTIR) study to create a reliable, detailed mineral map of the Tabba Tabba pegmatites.
Additionally, it plans to finalise its first exploration drilling at its Pilgangoora North and Bolt Cutter East prospects within the greater Tabba Tabba project area and to complete its permitting and other technical evaluation studies for the project.
Wildcat is well-funded to continue its exploration and to advance its development studies at Tabba Tabba this year, with $77.2 million cash in the kitty as at mid-year.
Rumble Resources
Western Queen project – Yalgoo Mineral Field, WA
Hit: 4m at 4.58 per cent tungsten trioxide from 174.85m
For something a little different, Rumble jagged this big tungsten hit in a diamond drillhole at its Western Queen gold project, 110km north-west of the regional centre of Mount Magnet in WA.
The headline hit includes 2.05m going 8.71 per cent tungsten trioxide from 176.85m and another 0.65m at an impressive 18.35 per cent from 176.85m. All three intercepts also carry gold ranging from 0.72 grams per tonne in the main hit, to 1.38g/t in the first included run and a peak of 2.97g/t gold in the final 0.65m interval.
While the purpose of the drilling was to identify extensions to known high-grade gold lodes, management says its new tungsten intercepts are “exceptional and well above grades of other tungsten resources globally”.
Rumble’s Western Queen project comprises two mining leases covering 9.8 square kilometres and is endowed with an indicated and inferred mineral resource of 2.1 million tonnes at 2.42g/t gold for a total of 163,000 contained ounces. Western Queen’s historical production amounted to 880,000 tonnes at 7.6g/t gold for 215,000 ounces and the mineralised zone is still viewed as being open down-plunge and along-strike.
A miscellaneous license also secures part of the original haul route – now an access road – between Western Queen and Dalgaranga, where the Dalgaranga mill processed the historic ore reserves from the Western Queen Central deposit.
The company’s mining leases are enclosed by three exploration licences that make up its fully contiguous Wardawarra project. The project is situated within 100km of three operating gold processing mills, with the 2.5 million-tonne per year Dalgaranga mill being the closest at only 48km by road.
Rumble believes both Western Queen and the greater surrounding Wardawarra ground have strong potential to increase the current gold inventory. More importantly, in the immediate tungsten context, the Western Queen Central deposit comes with a high-grade gold skarn in ultramafic rocks where historic production averaged 8.9g/t gold.
Tungsten-wise, skarns are often significant.
Fortunately, Rumble analysed all of its drillholes for tungsten by portable x-ray fluorescence (pXRF) as part of its 2021 Western Queen gold resource estimate. The pXRF results should be taken as qualitative only and may not reflect true tungsten grades, but they are a good guide to identifying runs with grade potential in the core.
A subsequent review of the pXRF results reveals that about 87 reverse-circulation (RC) and diamond drillholes put in by the company report tungsten metal levels above 500 parts per million tungsten. And contouring of the pXRF results unveils strong, coherent tungsten continuity over 2km within a greater than 100ppm tungsten metal contour.
The tungsten contours are perfectly coincident in strike, orientation and position with the Western Queen shear zone that hosts the gold.
Moreover, between the Western Queen Central and Western Queen South open-pits, the tenor of tungsten increases significantly, grading better than 1000ppm tungsten for an along-strike distance of about 900m.
Tungsten is classified as a “critical raw material” of high economic importance. It is among the most important metals on the critical materials list and subject to extreme supply risk.
Uses for tungsten are many and varied and include battery cathode and anode manufacture, as niobium tungsten oxide in batteries to reduce charge time and increase power density, as tungsten hexafluoride gas to optimise semiconductor production, as tungsten wire to replace diamond wire for photovoltaic cell silica wafer production and as a tungsten oxide coating to enhance hydrogen fuel cell durability.
The current 78,000-tonne annual supply of tungsten is dependent on China, which produces 81 per cent of the world’s product. But due to diminishing reserves and grades, the Chinese supply is forecast to decline.
Rumble is currently on a mission to re-assay laboratory pulps from its gold resource drilling, selected on the basis of its previous pXRF tungsten results, to determine spatial variability and tenor of its scheelite mineralisation. The company is looking at taking up to 250 pulps from selected RC and diamond holes to submit them for wet analysis.
The tungsten occurrence at Western Queen may not seem to have the tonnages we see from other Australian deposits, but some of the reported grades exceed those in other local deposits by several times. If tungsten – especially around the grades indicated – can provide a useful second credit to the company’s bow, its Western Queen project could really be ready to rumble.
Strickland Metals
Rogozna gold and base metals project – Serbia
Hit: 89.7m at 4g/t gold from 244.5m including 24.1m at 10.5g/t gold from 296.2m.
Strickland’s well-known Midas touch, which became apparent at its Yandal project in WA, seems to have rubbed off on the drill bit in the company’s first diamond hole put into the Shanac deposit at its recently-acquired, 100 per cent-owned Rogozna project in Serbia.
Management says the aim of its current program is to sniff out higher-grade gold zones at Shanac and upgrade its inferred resource of 4.6 million gold equivalent ounces. The latest hole was drilled about 200m north of the southern end of the Shanac deposit, targeting a zone of strong gold and copper mineralisation hosted by a magnetite skarn that was defined by previous drilling.
The drillhole encountered multiple, geologically-distinctive zones of gold and associated base metal mineralisation throughout its length.
It initially encountered 50.4m of a relatively shallow epithermal gold-lead-zinc-silver zone in andesites between 162.3m and 212.7m depth, including 10m going 0.4g/t gold, and 135g/t silver from 186.3m. Unsated, the hole bored on relentlessly for another 31.8m before beginning its thrust through the headline intercept in a gold-rich skarn contact zone at the base of the andesites.
The intercept proved to be the highest gold grade ever recorded from the Rogozna project before the zone ended at 334.2m. The headline discovery is the first time the high-grade, gold-only zone has been intersected at Shanac, highlighting considerable potential to fulfill the goal of the program – to identify new zones with the potential to further build the Shanac resource.
Importantly, the skarn zone had barely been tested owing to the open 60m to 80m drilling pattern employed in previous exploration. And while that intercept was exceptional, there was more drilling to come and after just another 14.8m, the hole plunged once more into a new encounter and an impressive 109.25m run in a copper-gold-magnetite skarn zone.
The zone averaged 1.3g/t gold and 0.4 per cent copper and includes multiple zones of massive chalcopyrite with grades attaining up to 11 per cent copper, before finally calling it quits at 458.25m.
The Shanac deposit is one of four skarn-hosted gold and base metals mineralised zones in Strickland’s Rogozna project, which currently contains an estimated gold equivalent endowment of 5.4 million ounces.
Strickland says its new results improve its understanding of the deposit and validates the company’s geological model for the controls on high-grade mineralisation at Shanac, which is starting to look now like a potentially big show.
As happens so often in geological exploration, even after thousands of metres of drilling and often after mines have been opened up to provide more of a 3D view of reality, we often see refreshed geological reinterpretations completely transforming both new and sometimes long-established projects.
Shanac seems to be a case-in-point.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
