Cosmo takes Mona copper-gold target to first drilling
Cosmo Metals has contracted Durock Drilling for up to 2,200 metres of maiden reverse-circulation drilling at the Mona prospect in New South Wales. The campaign will test whether exceptional copper, gold and silver grades from historic mine dumps reflect mineralisation continuing beneath the old workings.
- Up to eight RC holes planned for approximately 2,200 metres
- Drilling to target copper-rich VMS sulphides and a possible gold-silver feeder zone
- Historic mine dump samples returned up to 4.93% copper, 11.65g/t gold and 204g/t silver
- Mona sits within the 5km Everest-Mona-Victory trend and broader 20km Bingara VMS belt
- Downhole EM is planned after the initial drilling campaign
Cosmo Metals Ltd (ASX:CMO) has moved its Mona copper-gold-silver target from geological theory to a drill rig contract, awarding Durock Drilling a program of up to eight reverse-circulation holes covering approximately 2,200 metres. It will be the first drilling campaign at the historic Mona mine, where mine dump samples have returned striking grades but have not yet demonstrated underground continuity.
Maiden drilling targets two mineralised zones
The initial holes are designed to pass through the copper-rich massive sulphide position beneath and along strike of the old workings, before testing a potential gold and silver-rich feeder zone. Cosmo says the program will use four approved drill pads, with up to two holes planned from each pad, although the final scope is capped rather than guaranteed at eight holes.
The target’s headline numbers come from grab samples rather than drilled intersections. Material interpreted to have come from the base of the historic workings included results of up to 4.93% copper, 11.65 grams per tonne gold and 204 grams per tonne silver. One sample returned 3.2% copper, 4.14% zinc and 3.18g/t gold. Those grades are potentially significant exploration signals, but they do not establish thickness, scale, continuity or an economic resource.
Geology points to a possible precious metals overprint
Cosmo’s interpretation is that the gold and silver-rich material may represent a later intrusion-related mineralising event overprinting the Mona volcanogenic massive sulphide system. The samples also carried elevated molybdenum, bismuth and tellurium, alongside cobalt depletion. The company considers the pattern consistent with remobilisation or leakage through feeder structures, but drilling will be needed to test whether that interpretation holds below surface.
Mona forms part of the 5km Everest-Mona-Victory trend at the southern end of the broader 20km Bingara VMS belt, which contains at least six recorded historic copper mines. Cosmo’s mapping, airborne magnetics, LiDAR and soil work have identified the possibility of stacked and concealed VMS horizons, giving the first Mona holes significance beyond a single old mine. A successful geological intersection could help guide exploration along the wider corridor, while an absence of continuity would limit the reach of the current model.
Site works precede drilling and downhole EM
Site preparation is now being coordinated around existing approvals and landholder engagement, ahead of rig mobilisation. Cosmo plans to follow the RC campaign with downhole electromagnetic surveying to search for lateral and down-dip extensions of any massive sulphide bodies identified. Separately, data from pXRF auger sampling at the Plunkett and Cassidy prospect within Antimony Gully is being collated for possible follow-up drilling targets.
The immediate test is straightforward but consequential: can a handful of holes convert spectacular waste-dump grades into coherent in-situ mineralisation with meaningful width and continuity? Until assays and geological intersections answer that question, Mona remains an attractive exploration target rather than a defined deposit.
Bottom Line?
The drilling contract removes a key execution hurdle, but the investment case now turns on whether historic dump grades are representative of mineralisation beneath Mona and how much of the system can be traced beyond it.
Questions in the middle?
- Will the first RC holes intersect mineralisation at grades, widths and depths comparable with the mine dump samples?
- Does the interpreted gold-silver feeder zone form a coherent system alongside the copper-rich VMS lode?
- Can downhole EM identify extensions that justify a larger drilling campaign across the Mona and wider Bingara trends?
