The State Government has thrown its financial grunt in behind Infinity Mining’s diamond drilling program at the company’s Tambourah South lithium project, with a $149,675 Exploration Incentive Scheme (EIS) grant.
Infinity will fund the balance of the $299,350 program, which will see the drilling of two inclined NQ-diameter diamond drillholes to depths of up to 300m to evaluate the geology underlying the extensive lithium-bearing pegmatite swarm at the project.
The EIS is an initiative kicked off by the Western Australian Government in 2009 in a bid to encourage exploration in the State and to encourage private sector resource exploration for new mineral and energy discoveries.
The Tambourah South project sits some 70km south-east of Pilbara Minerals’ massive Pilgangoora lithium venture and 95km south-west of Global Lithium Resources' Marble Bar lithium project. Geologically, it lies within greenstones of the Apex basalt adjacent to the Yule granite complex and covers the highly-prospective pegmatite-favouring “Goldilocks zone” out to about 3km from the granite-greenstone contact.
Infinity Mining chief executive officer Joe Groot said: “Tambourah South has made significant progress since our EIS application was lodged, recently returning high-grade lithium oxide results from both surface sampling and RC drilling. Diamond drilling will provide vital geological information about the nature of the pegmatites in the project and test the ability of passive seismic to discriminate pegmatites at depth and the nature of the host rocks, both of which will greatly improve our on-going exploration and 3D geological modelling.”
The lithium-bearing pegmatites of the Tambourah project lie within greenstones of the Archean Western Shaw greenstone belt, adjacent to the Shaw granite batholith – a major granitoid body.
Recent drilling by the company of eight reverse-circulation (RC) reconnaissance drillholes for 834m at the McNeills and Grumpy targets in the project produced several outstanding shallow lithium-caesium-tantalum (LCT) intercepts in a big swarm of stacked pegmatites. The top lithium grades in analytical results from the RC drill chips in 1m intercepts were 0.99, 1.41, 1.45 and 2.1 per cent lithium oxide, in addition to a 2m intercept at 1.38 per cent lithium oxide.
Elemental lithium was also shown to be running at more than 1200 parts per million to a maximum of 9770ppm lithium and most of the analyses feature elevated rubidium, caesium and tantalum values.
Infinity says that while lithium results from the program vary considerably, the fertility of the overall system is reflected not just by several solid LCT drill intercepts, but also by the use of a portable spectrometer, which confirms spodumene to be the dominant lithium-bearing mineral.
Additionally, throughout almost all the drilling, rubidium and caesium analyses were commonly elevated. Rubidium was reported to a maximum of 1m at 2040ppm and caesium attained a peak grade of 1m at 136ppm.
Infinity’s exploration licence features a vast swarm of pegmatites evident at surface, almost all with a north/north-easterly strike, but clustered as a group along a north-south corridor along the western side of the licence. It seems unlikely that many have been tested in the current lithium context – if ever.
The company attributes its successful co-funding award in the competitive EIS program to its geologically-sustainable model for the potential styles of mineralisation. The model considers all previous surface geological and structural mapping and geochemistry, in addition to recent RC drilling results that highlight a favourable LCT environment.
The company has integrated that into the results of its passive seismic survey to produce a preliminary 3D block model for the project. The block model is used to identify bigger pegmatite bodies at depth, which could be roots or feeder zones to the pegmatites mapped at surface.
At this stage, two bigger possible pegmatite bodies have been identified in the block model as shallow, flat-lying, low-density zones below the mineralisation logged in the company’s recent RC drilling and surface sampling. The bodies will be targeted by the deep diamond holes.
The entire program will not only prove or disprove the validity of Infinity’s model, but if successful, it will potentially go a long way to uncovering previously unknown relationships between deep pegmatite feeder zones and their myriad of surface expressions as vein swarms.
The company also made some boardroom changes yesterday with Groot resigning as chief executive officer, but with plans to remain as a director. Harley Groot stepped down from his role as a non-executive director, but plans to remain as Infinity’s senior exploration manager.
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By Doug Bright
