Results from a diamond drilling program by Alliance Resources (ASX: AGS) at the Yeltana graphite prospect in South Australia indicate the company could be on the verge of owning the nation’s largest graphite discovery by mineral content.
The program this week returned significant graphite-bearing intervals showing “excellent correlation with a highly-conductive source” beneath existing holes at the prospect, which sits within the Wilcherry project joint venture between Alliance (75.01% and manager) and Tyranna Resources (24.99%).
Intersections averaging greater than 5% total graphitic carbon (TGC) were encountered with best results including 17.2 metres at 5.05% TGC from 234.; 17.1m at 8.54% TGC from 148m; and 21.05m at 9.28% TGC from 171.75m.
The results were combined with geophysical data and used to form the basis of an estimated exploration target at Yeltana of between 24.5 million tonnes and 59 million tonnes, with grades from 5.5% to 10.2% TGC.
The largest in Australia?
According to Alliance, the size of the exploration target is “nationally significant” as the estimated tonnage and grade ranges indicate it could well be one of the largest of its kind in Australia by mineral content.
But the estimation is early stage, and confirmation will rely on results of additional work at the prospect.
“Further work is needed to advance [our] understanding of the mineralisation, including graphite flake size distribution to better assess the economic potential of the prospect before further drilling [can be planned],” the company said.
“This will initially consist of preliminary metallurgical testwork and if warranted, development of a systematic exploration drilling and metallurgical testing program to define an appropriate sized mineral resource for exploitation.”
Assessment of Yeltana’s economic potential will take place in parallel with the development of Alliance’s nearby Weednanna gold deposit, where it debuted a maiden mineral resource last month.
A “strong and dominant anomaly”
The Yeltana prospect was identified in early 2017 by a helicopter-borne electromagnetic survey and more accurately defined midyear by a high powered, moving-loop EM survey which identified a single strong bedrock anomaly modelled as approximately 600 metres by 1200 metres in size, starting from 50m below surface.
In November, a reverse circulation drill hole confirmed the anomaly to be associated with a broad zone of graphite mineralisation, returning 39m at 8.0% TGC from 116m.
Earlier this year, two diamond holes were drilled at Yeltana to confirm the initial RC intersection.
Alliance also aimed to complete downhole EM surveys to better model the size and geometry of the graphite conductor, and provide empirical data to support the exploration target estimation.
Data from both holes highlighted a “very strong and dominant inhole anomaly”, with the source predominantly below the holes and related to well-developed graphite and sulphides.
A high demand mineral
Graphite is in increasing demand to support battery technologies relating to emerging electric vehicle and green energy markets.
Flake size distribution is a key consideration for mining companies – larger flakes mean higher purity and higher market prices.
Graphite purity is particularly important for high-value end uses such as lithium-ion batteries and is a key determinant in saleability of product.
It is also a key factor in the cost of production – project operating costs can dramatically increase when further processing is required to make graphite product market-ready.
At midday, shares in Alliance Resources were trading 9.09% higher at $0.12.