Cosmo Metals Wins Approval to Drill Beneath Century-Old Copper-Gold Mine

Drilling approved at Mona — Cosmo targets high-grade copper-gold beneath a century-old mine

Cosmo Metals (ASX: CMO) has received approval from the NSW Resources Regulator for the first-ever drilling beneath the historic Mona Volcanic-hosted Massive Sulphide (VMS) mine, located within the 5km Everest-Mona-Victory VMS Trend at the Bingara Project in New South Wales. The approved program covers up to 8 drill holes for approximately 2,200m, targeting high-grade copper-gold mineralisation that early 1900s miners could not reach with the technology of their era.

What makes this approval particularly compelling is the surface sampling story that preceded it. Mine dump grab samples from Mona returned results of up to 4.93% Cu, 11.65g/t Au, and 204g/t Ag, with mapping and field investigations indicating this high-grade material originated from the base of the historic workings — material left behind, not depleted.

The surface sampling campaign that underpins this drill approval built on a body of prior work confirming high-grade copper gold silver at Bingara, with that earlier dataset shaping the structural interpretation of where mineralisation concentrates beneath the historic workings.

Mobilisation is being fast-tracked, with advanced contractor engagement already underway.

Key program statistics at a glance:

• Up to 8 drill holes, approximately 2,200m program
• Surface grab samples: up to 4.93% Cu, 11.65g/t Au, 204g/t Ag
• Located within the 5km Everest-Mona-Victory VMS Trend
• Part of the broader 20km Bingara VMS Belt, hosting at least 6 recorded historic copper VMS mines

What is VMS mineralisation — and why does it matter here?

Volcanic-hosted Massive Sulphide (VMS) deposits form on ancient seafloors when superheated, metal-rich fluids are expelled through volcanic vents and rapidly cool on contact with seawater. That rapid cooling causes metals — primarily copper, zinc, gold, and silver — to precipitate and concentrate into dense, high-grade sulphide lenses. The result is typically a compact but extremely rich ore body.

At Bingara, the style of mineralisation is consistent with what geologists call a Cyprus-style VMS deposit: modest in overall tonnage but high-grade in copper, with associated gold, silver, and zinc. Critically, this style of deposit tends to occur in clusters, forming what the industry calls a “deposit camp.” That cluster potential is why the 20km Bingara VMS Belt matters so much strategically — a successful discovery at one point along the trend raises the probability of finding additional deposits elsewhere along it.

There is a second layer of complexity at Mona that adds meaningful upside. The high-grade gold and silver samples also contained elevated molybdenum (to over 200ppm), bismuth and tellurium anomalism, and cobalt depletion. This geochemical signature indicates a secondary mineralising event, interpreted by the Cosmo project team as an intrusion-related gold (IRG) overprint. In plain terms, a later mineralising event has remineralised the feeder structures of the original VMS system, potentially upgrading the overall precious metals endowment of the target. This gives the maiden drill program two distinct ways to make a significant discovery.

What Cosmo is targeting underground at Mona

The initial drill holes at Mona are designed to test two overlapping targets. The first is the primary copper-rich VMS lode position directly beneath and along strike of the historic mine workings — the massive sulphide body that the early miners were working toward but could not fully exploit. The second is the potential gold and silver-rich feeder zone beneath that, informed by the IRG overprint signature identified in the surface sampling.

Think of it as a two-storey target. The upper zone is the copper lode; the zone below is the precious metals-enriched feeder channel that fed the system. Both represent potentially significant mineralisation, and the initial holes are designed to pass through both.

The high-grade mine dump material — which is interpreted to represent some of the last material removed from the base of the workings — reinforces the geological case. That material could not be economically processed in the early 1900s and was effectively abandoned in place, not exhausted.

The broader Everest-Mona-Victory Trend context adds further confidence. Investigation of the Sweet Nell prospect to the east of Everest indicates that prospective target horizons may be stacked in the stratigraphy, increasing the probability of concealed and stacked VMS mineralisation across the trend.

Ian Prentice, Managing Director

“This first ever drilling of an old mining field is incredibly exciting, with the aim of discovering high grade sulphide rich mineralisation below the existing workings that couldn’t be exploited by the miners in the early 1900’s.”

Key sample results from Mona mine dumps:

Note: Sample IDs for the headline grab results are not individually specified in the source announcement. Figures are as reported in the CMO ASX announcement dated 2 June 2026.

What comes next — and the scale of the broader opportunity

With regulatory approval now in hand, the forward work program is sequenced as follows:

1. Finalise documentation and complete local landholder engagement to enable preparation of the approved drill sites
2. Mobilise the drilling contractor as soon as possible, with advanced engagement already progressing in line with these activities
3. Expect to complete a downhole electromagnetic (DHEM) program following the initial drilling campaign, designed to identify lateral extensions of any identified massive sulphide bodies for subsequent drill testing
4. Collate and interpret pXRF auger soil sampling results at the Plunkett and Cassidy prospect at Antimony Gully, with the aim of defining targets for follow-up drill testing

Separately, antimony mineralisation at Bingara has been defined through surface sampling at the Antimony Gully prospects, adding a distinct critical minerals dimension to the project portfolio alongside the VMS copper-gold work.

The Mona maiden drill program is the first step in demonstrating the potential of the full 20km Bingara VMS Belt. That belt hosts at least 6 recorded historic copper VMS mines, all of which have seen little to no drilling by modern standards. The Mona prospect is the first within this belt to be drill tested beneath its historic workings.

A successful discovery here would not only validate the Mona target but could de-risk the broader Everest-Mona-Victory Trend and point toward repeated targets along the full extent of the belt. The cluster model that underpins Cyprus-style VMS systems means that each confirmed deposit increases the prospectivity of its neighbours — and at Bingara, the neighbours remain largely untested.

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