Key Highlights

  • GBM Resources Ltd (ASX:GBM) was trading at A$0.018, down 10.00%, during the 23 October 2026 trading session.
  • On 21 October 2026, the company reported rougher flotation gold recoveries of 92% to 99% from the 309 and Lone Sister deposits at Twin Hills.
  • The company said further flotation optimisation and leach testwork are required before a preferred processing flowsheet is determined.

GBM Resources Ltd (ASX:GBM) shares were trading at A$0.018, down 10.00%, during the 23 October 2026 trading session, compared with the S&P/ASX 200 (XJO), which was at 8,760.50, down 0.37% (32.70 points) at 1:16 pm AEDT. GBM is a Queensland-focused gold exploration and development company with projects in the Drummond Basin. In an announcement released on 21 October 2026, the company reported initial metallurgical testwork results from the 309 and Lone Sister deposits at its Twin Hills Gold Project, covering rougher flotation and cyanide leaching.

Latest Developments

Rougher Flotation Results

On 21 October 2026, GBM said independent metallurgical consultant Core Resources completed four preliminary rougher flotation tests on composites from the 309 and Lone Sister deposits, at grind sizes of 75 and 45 microns. Gold recoveries exceeded 90% in all tests, ranging from 91.9% to 99.0%. At the 75-micron grind, 92.0% of the gold at Lone Sister reported to 4.8% of the feed mass, grading 26.0g/t gold, while 98.9% of the gold at 309 reported to 8.7% of the feed mass, grading 18.0g/t gold. The company said the finer 45-micron grind provided no material improvement in rougher recovery.

The company noted that recoveries represent cumulative rougher flotation results and that final process recoveries will depend on subsequent cleaning and concentrate treatment.

Cyanide Leaching Results

GBM reported on 21 October 2026 that 48-hour carbon-in-leach (CIL) bottle roll tests at Lone Sister returned gold extractions of 87.3% and 88.8%, which the company said were consistent with historical testwork. At 309, current CIL extractions without gravity separation were 25.2% at 75 microns and 47.5% at 45 microns, below results in several historical programs that used gravity and CIL, where recoveries of 92.8% to 96.4% were reported. The company said significant variability in repeat gold assays suggests coarse or unevenly distributed gold may be affecting sample representivity. It also reported low arsenic content of 88ppm in the 309 composite and said the lower CIL extractions remain somewhat unexplained.

Next Phase of Testwork

The company said the next phase will focus on flotation optimisation, concentrate cleaning and upgrading, gold assay verification, assessment of gravity-recoverable gold, and cyanide leaching of flotation concentrates and whole-ore CIL options. GBM stated that it remains too early to select a preferred processing flowsheet, and that further results will be reported as the program progresses. Chief Executive Officer Daniel Hastings described the initial results as encouraging and said establishing an effective and commercially viable recovery process is an important component of progressing Twin Hills towards development.

About GBM Resources Ltd

GBM Resources Ltd is a Perth-based mineral exploration and development company focused on gold deposits in Queensland. According to the company, its portfolio is located within the Drummond Basin and holds approximately 1.84 million ounces of gold in Mineral Resources across its flagship assets, Twin Hills, Yandan and Mt Coolon. The Twin Hills Gold Project has an existing Mineral Resource of approximately 1.0 million ounces of gold across the 309 and Lone Sister deposits, according to the 21 October 2026 announcement.

Related Sector Context

GBM operates in gold exploration and development within the ASX Mining sector. Companies at the project definition stage commonly undertake metallurgical testwork to assess how much gold can be recovered and by which processing route, with Options including flotation, gravity separation and cyanide leaching. The announcement discussed conventional flotation and CIL processing, and the company said historical metallurgical work at Twin Hills has also been extensive. On 23 October 2026, the S&P/ASX 200 was at 8,760.50, down 0.37%, a smaller move than that in GBM shares.

Risks to Weigh In

  • A preferred processing flowsheet for Twin Hills has not been selected, and the company said further work is required.
  • Current CIL extractions at 309 were below historical results, and the company said the variability is not yet fully explained.
  • Rougher flotation recoveries are preliminary, with final recoveries dependent on cleaning and concentrate treatment.
  • Coarse or unevenly distributed gold at 309 may affect sample representivity, according to the company.
  • The company is an exploration and development Business and has not announced a development decision for Twin Hills.

Catalysts on Watch

  • Flotation optimisation work, including reagent selection, concentrate cleaning and upgrading.
  • Additional leach testwork at 309, including assay verification and assessment of gravity-recoverable gold.
  • Cyanide leaching of flotation concentrates and further whole-ore CIL assessment.
  • Further metallurgical results, which the company said will be reported as the program progresses.

Final Takeaways

GBM Resources shares were trading at A$0.018, down 10.00%, during the 23 October 2026 trading session, against a 0.37% decline in the S&P/ASX 200. The company's announcement of 21 October 2026 reported rougher flotation gold recoveries of 92% to 99% and mixed cyanide leaching outcomes at Twin Hills, with further testwork planned. The company has said it will report additional results as the program progresses.