In 2018, an independent resource estimate, reported in accordance with JORC, established a partly inferred/partly indicated resource of 4.28 million tonnes at a grade of 0.45% Cu. This is a large resource at a significant grade but falls short of the tonnage required for commercial development.
Included in the 2018 JORC-compliant independent resource report were the following two statements:
(1) The deposit contains a central area, 300 meters in length, which has only been tested by two drillholes. This area is given a high probability of containing additional resources. At a finding rate of 3,505 tonnes per meter we assume a probably target of 1 to 3 million tonnes, grading 0.4 to 0.6 percent total copper.
(2) The area of M2 IP anomaly comprises 163 hectares. Deducting the drilled area, which comprises 33 hectares, the target area consists of 130 hectares. Assuming a 65% probability of success, this target would consist of 9 to 14 million tonnes grading 0.4 to 0.6 percent total copper.
As the areas referred to in (1) and (2) above have not yet been drilled, they are categorised as Exploration Targets in JORC terminology and cannot be categorised as Resources. The recent review of all available data, considering the independent report on M2, has re-emphasised the exciting potential for M2 which significantly exceed the Resource already reported.
If these independently calculated Exploration Targets prove to be correct, the Resource and the Exploration Targets together at M2 could become 14.3 - 21.3 million tonnes at 0.4 - 0.6 % copper; several times larger than the existing Resource. Such an increase would be transformative for Great Western.
Along with the potential for extension in the central portions and to the southwest, a trend of surface showings extends at least a further 1.5 km to the northeast, all within the Company’s claims. The northeastern most drillhole in the resource ended in grade, below the depth of surrounding holes – this specific zone is open in all directions.
The Little Huntoon Valley is a half graben, tilting towards the M2 escarpment to the southeast. Further potential exists in the downthrown block beneath the valley sediments. Exposed granite to the northwest features aplite dykes with pegmatitic zones.
View a map of the M2 prospect within the Black Mountain claim group
View a map of the regional setting of Great Western’s claims within an extensively-mined area
M2 occurs at and around the contact of a diorite with the overlying sedimentary sequence, and particularly limestone horizons within that sequence. The layered sequence dips gently to the east-southeast, and forms a likely half graben escarpment, with the Little Huntoon valley representing the down thrown block. Although the system has been interpreted as a skarn forming due to the intrusion of the diorite into a carbonate sequence, recent fieldwork (2024) has uncovered evidence of mineralisation occurring with a late felsic phase that apparently crosscuts the diorite. Steeply dipping aplitic dykes, which outcrop at surface to the northeast with associated copper mineralisation, and chips of similar material occur in or closely adjacent to several of the mineralised intercepts in the drillholes.
To the northeast of M2 exposures of coarse granite at Fletchers Camp bear strong resemblance to the Whiskey Flat granite outcrops north and east of West Huntoon. This granite has been found to be geochemically fertile on the basis of both whole rock and zircon geochemistry. Upper parts of the Fletchers Camp granite contain aplitic and pegmatitic zones which appear to break through the carapace into the overlying sediments in this area. These are likely the same aplites which are observed with copper mineralisation where they cross the host rock nearby.
The M2 resource is interpreted as stratabound, dipping to the southeast beneath the crest of Black Mountain, likely with the general half-graben tilt of the horst block in this area. On the southwestern side of the same massif, the Smith mine workings occur. Both are associated with felsic intrusions in sediments, again linking local mineralisation to a widespread mineralising granitoid phase.
GWM has previously investigated a target concept named ‘Sharktooth’ which is a deeply buried zone hypothesised to be a continuation of the M2 and Smith Mine mineralisation, centred beneath the Sharktooth peak in the middle of the ridge. Several deep drillholes were designed to test this target, and some did detect elevated copper values towards their deeper portions, but each was discontinued for technical reasons before reaching target depth. The Sharktooth target remains insufficiently tested.
Download The Report of Mineral Resources Modelling at M2 Project.