Special Report: Gateway’s aircore drilling has identified the Achilles prospect as a major new gold target after defining mineralisation over a 2.5km corridor.

Wide-space drilling has returned assays of up to 16.2 grams per tonne (g/t) gold and defined high-order oxide and primary gold anomalies, extending the existing Achilles oxide target for a further 1.4km strike length to the immediate south of the historical Rosie open pit.

Gateway Mining (ASX:GML) says the results now confirm the presence of significant gold mineralisation along multiple mineralised thrust structures that run along the margin of and internal to the western margin of the Montague Granodiorite within its Gidgee project in Western Australia.

It added that the Achilles trend includes a series of historical prospects where previous drilling had returned high-grade gold hits such as 20m at 15.6g/t gold from 25m, 17m at 14.7g/t gold from 30m and 5m at 22.2g/t gold from 37m.

“Seeing assay results as high as 16g/t for this relatively early stage of aircore drilling is always exciting, but of greater importance is the continuity and strength of the oxide and primary gold anomalism and the logical correlation of the geology and structures across the 1.4km strike extent,” managing director Peter Langworthy said.

“The position of the cross-cutting structures within the Montague Granodiorite is a highly favourable location for major gold deposits to form.

“What we are seeing in the Achilles Gold Corridor is a favourable coincidence of geological structures with high-order gold anomalism, which suggests that we could be in the early discovery stages of a major new gold system.”

He added that the correlation with high-grade historical results and the way the Achilles trend lines up with shallow oxide mineralisation defined to the north is quite remarkable and warrants further work.

“It’s still relatively early days for the Achilles Gold Corridor, but we see a big opportunity emerging there that could well end up ranking a close second in priority behind the North West Margin, where we are working to in-fill the 1.5km area between our two cornerstone deposits,” Langworthy noted.

“Once again, this reinforces the multi-pronged opportunity we have at Gidgee and the enormous potential to discover major new gold deposits.”

Gateway Mining drilling aircore gold
Achilles South aircore drilling results. Pic: Supplied

Aircore drilling

The aircore drilling program was designed to test the immediate southern extension to the Achilles target area where recent reverse circulation drilling has continued to extend near-surface mineralisation north of the historical Rosie open pit.

This program of 305 holes totalling 15,016m has succeeded in delineating several coherent oxide-zone anomalies that are interpreted to emanate from bedrock-hosted primary mineralisation at depth.

When combined with effective historical drilling, several previously recognised prospect areas – such as Airport, L.A. International and Dandelion – can now be interpreted across the Achilles corridor.

Importantly, the air-core results appear to support the theory that a splay from the Achilles shear corresponds to the historical Airport and Airport South prospects, where extensive shallow high-grade mineralisation has been identified by previous explorers.

This mineralised trend can be traced back into the main Achilles Shear structure, making it a significant target for deeper RC testing.

A new, previously unrecognised mineralised structure has also been identified within the granodiorite body, on the eastern extent of the recently completed air-core pattern, and appears to correspond to a diffuse north-northwest trending structure within the intrusion.

This structure appears to be a splay off the main Achilles Shear, and can be traced over approximately 2.5km in aeromagnetic data.

Langworthy says the area clearly warrants further work and that the company plans to carry out some initial reconnaissance RC drilling followed by infill aircore drilling to prioritise areas for RC and diamond drilling.

Follow-up RC drilling will also be designed to provide deeper bedrock context on the anomalies identified by the aircore program and to identify potential ore grade sources to the oxide-zone gold dispersion halos.


Other activity

Gateway continues to progress RC drilling testing the northwestern contact of the Montague Granodiorite, the “North West Margin” area, as well as infilling the high-grade shoots at Montague/Boulder.

This drilling has been ongoing since mid-September and is forecast to be completed in the second half of November.

While no assays have been received as yet due to the WA-wide surge in samples submitted to commercial assay laboratories, the company expects to receive the majority of results by mid-December.

Planning is underway for the re-commencement of field programs in 2021.

The company has also applied for a grant from the WA State Government Exploration Incentive Scheme for four deep diamond holes.

These will test the nature of the Montague Granodiorite intrusion and the stratigraphy and deformation of the prospective mafic volcanic host sequence on both the western and eastern contact margins.


This article was developed in collaboration with Gateway, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.