QMines (ASX: QML) has begun the first diamond drilling beneath the flooded historic Mt Chalmers open pit in central Queensland.

The copper-gold developer is using a purpose-built floating platform to reach mineralisation locked beneath the pit lake for decades.

Main image: Drilling preparations at the flooded Mt Chalmers open pit

QMines said the program would test extensions to the deposit, which remained open along strike and at depth.

It also aimed to lift confidence in an existing Inferred Resource and convert it into ore reserves to support a feasibility study.

Much of that material was drilled decades ago using percussion methods that do not meet the quality standards required under the current JORC Code.

Floating Drilling

The pontoon drilling forms part of a 10,000-metre campaign supporting the Mt Chalmers definitive feasibility study, with first core already recovered.

After drilling beneath the pit near Rockhampton, the rig would move to the Woods Shaft deposit for a major resource-growth program.

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QMines executive chairman Andrew Sparke said the program had the potential to create value in two ways.

“Firstly, we’re drilling beneath the existing pit where the deposit remains open at depth, providing an opportunity to grow the Mineral Resource. Secondly, we’re upgrading confidence in existing mineralisation beneath the pit, creating the opportunity to convert additional resources into Ore Reserves that can support the Definitive Feasibility Study and potential for a larger or longer mine plan.

“This mineralisation has effectively been out of reach due to the flooded historic pits. The floating drilling platform now gives us access to an area that has never been systematically tested using modern diamond drilling techniques.

“I’d also like to congratulate United Drilling Services on an outstanding job. Mobilising and operating a diamond drill rig from a floating platform is no easy task and their team has executed the project safely and professionally. First core has already been recovered and we’re looking forward to seeing what lies beneath the historic mine workings.

“Importantly, this is only the beginning. The Company is already making plans to mobilise another drilling rig to Woods Shaft where we’ll be targeting additional resource growth as part of our broader 10,000 metre drilling campaign. We believe the coming months will deliver a strong pipeline of news flow and several exciting catalysts for our shareholders.”

Mt Chalmers holds an ore reserve of 9.6 million tonnes and a mineral resource of 11.3 million tonnes at 0.75 per cent copper.

The historic mine produced 1.2 million tonnes at 2.0 per cent copper, 3.6 grams a tonne gold and 19 grams silver between 1898 and 1982.