Emerging explorer FireFly Metals (ASX: FFM) has confirmed a 42% upgrade to the mineral resource estimate (MRE) at its Green Bay copper-gold project in Canada.

The total measured and indicated resource now sits at 59 million tonnes grading 2% copper-equivalent for 1.2Mt of contained metal across two deposits at Little Deer (9.1Mt at 2.0% CuEq) and the underground Ming mine (containing 49.9Mt at 2.0% CuEq).

Copper is the dominant contained metal – totalling 1Mt – and has increased by 39% on the original MRE, alongside 550,000 ounces of gold (up 48%) and 5.4Moz of silver as co-products (up 57%).

Low-cost strategy

The MRE upgrade was driven by a low-cost, rapid resource growth strategy implemented by FireFly after it acquired Green Bay in October 2023.

Over 1,400 metres of underground development has since been established at Ming, allowing for drill rig positioning to effectively test down-plunge extensions of the high-grade volcanogenic massive sulphide (VMS) mineralisation and broad footwall copper stringer zone (FWZ).

Up to four rigs have completed approximately 40,000m of diamond drilling to date over a 2-kilometre strike length, with the VMS and FWZ remaining open and indicating probable extensions to the mineralisation.

The total discovery cost per estimated tonne of copper-equivalent metal added to the resource is reported to be an industry-low $79/t.

Genuine scale

Managing director Steve Parsons said the resource upgrade confirmed Green Bay’s global status as a fast-growing, high-grade copper project with genuine scale.

“To achieve such immense growth in a short time and at such little cost highlights the top-shelf quality of this project, as well as the skill of our team and commitment to multi-rig drilling programs,” he said.

“These same factors will drive the next round of resource growth, enabling us to capitalise on the open nature of the mineralisation and the potential for new discoveries.”

FireFly has planned a total 130,000m campaign to extend the resource and convert inferred areas to indicated for inclusion in future mining studies, with resource updates in the new year expected to include high-grade copper- and gold-rich massive sulphide lenses and potential resource extensions.