Celsius Resources Ltd (ASX:CLA, AIM:CLA) has delivered an updated JORC-compliant Mineral Resource Estimate (MRE) for its Maalinao-Caigutan-Biyog (MCB) Copper-Gold Project in the Philippines, marking a step-change in confidence as the project advances towards a revised Feasibility Study and front-end engineering design (FEED) in December.
The global resource now stands at 343 million tonnes at 0.46% copper and 0.12 g/t gold, representing 1.6 million tonnes of contained copper and 1.4 million ounces of contained gold at a 0.2% copper cut-off grade.
Celsius holds a 40% working interest in the project via its affiliate Makilala Mining Co. Inc. and has conditionally agreed to transfer a 60% interest to Sodor Inc., subject to outstanding conditions.
Location of MCB Exploration Tenement area and associated drilling related to the reported MRE.
Confidence boosted with larger Measured category and stronger high-grade core
A key outcome of the updated estimate is a substantial lift in the Measured category, which now sits at 49 million tonnes at 0.60% copper and 0.19 g/t gold. Drilling completed in 2022 and 2025 — primarily for metallurgical sampling and geotechnical work — has confirmed mineralisation continuity and tightened resource boundaries.
Section 1 with the interpreted host rock geology relative to the defined copper mineralised domains. Drill holes completed after the 2022 Mineral Resource Estimate on this cross section are identified (holes MCB-042, MCB-043, MTPH-001, and MCB-UG-002). View looking Northeast.
The refined model also defines a high-grade core of 99 million tonnes at 0.79% copper and 0.24 g/t gold (0.5% copper cut-off) within the Measured and Indicated categories, further underpinning the project’s economic potential.
Overall, the 2025 update adds 5 million tonnes containing 14,000 tonnes of copper to the previous 2022 resource.
MCB Project drill hole locations and interpreted surface geological plan view diagram
Makilala technical director Peter Hume said that while the drilling program focused on feeding the updated Feasibility Study and FEED work, the company was “pleasantly surprised” with the high-grade results returned.
“These results, along with the recently announced recoveries, will further underpin the MCB Project’s economic viability and will be the basis of the JORC mining reserve which is part of the updated Feasibility Study and FEED work program,” Hume said.
Section 2 with the interpreted host rock geology relative to the defined copper mineralised domains. Drill hole completed after the 2022 Mineral Resource Estimate on this cross section is identified (MCB-UG-001). View looking Northeast.
Resource refinements support upcoming reserve and feasibility work
Celsius said additional drilling has sharpened the definition of the mineralised system, improving confidence in key domains and enabling more robust grade distribution at higher cut-off grades. The company also updated its weathering model, which removes the Inferred category from shallow weathered zones and retains this material for future evaluation.
The 2025 MRE will underpin the project’s maiden JORC mining reserve, which is scheduled for delivery as part of the Feasibility Study update due by year-end.
A long-life copper-gold opportunity in the Philippines
MCB is located in the Cordillera Administrative Region, around 320 kilometres north of Manila, and remains Celsius’ flagship asset. A 2021 study outlined the potential for a long-life underground operation producing copper-gold concentrate over a 25-year mine life, supported by a 2.28-million-tonne-per-annum processing plant.
Location of the MCB Project in the province of Kalinga, Northern Luzon, Philippines.
That study returned a post-tax net present value (NPV8) of US$464 million, an internal rate of return (IRR) of 31%, and a payback period of 2.7 years, based on a copper price of US$4.00/lb and gold at US$1,695/oz. Average C1 cash costs were estimated at US$0.73/lb, net of gold credits.
Ongoing studies are now updating those metrics, with the company incorporating its refined resource model, improved metallurgical recovery data — averaging 95% for copper and 77% for gold — and enhanced understanding of ore types across the deposit.
With FEED work nearing completion and the JORC reserve in sight, Celsius says the updated MRE provides a stronger technical foundation for the next phase of development at MCB.