From Discovery to Engineering: De-Risking the Buen Retiro Heap Leach

• Fitzroy Minerals has sent a 2,900 kilogram representative sample to SGS Laboratories, marking a critical transition from exploration to engineering at the Buen Retiro Pre-Feasibility Study (PFS).
• The Company has defined 3 primary geo-metallurgical domains - Higher-Grade Oxide, Lower-Grade Oxide, and Higher-Grade Mixed Supergene Transition - to optimize leaching treatment strategies and de-risk recovery assumptions for the PFS.
• Definition drilling with 2 rigs is focused solely on material down to a maximum depth of 150 metres, targeting a maiden mineral resource estimate to support near-term heap leach production.
• Fitzroy is targeting a heap leach joint venture with Pucobre, which operates an existing solvent extraction-electrowinning (SX-EW) plant with a capacity of 800 tpm.
• Upon completion of definition drilling in May, one drill rig will be re-allocated to a minimum of 8,000 metres of Phase 3 exploration drilling to test deep sulphide targets identified by a newly completed ambient noise tomography (ANT) geophysical survey.

What Has Happened

Fitzroy Minerals Inc. [TSXV: FTZ | OTCQX: FTZFF | FSE: C3Y]  has completed 32 diamond drill holes totalling 5,143 metres in the southwest area of Buen Retiro, targeting oxide, mixed, and supergene material to a maximum depth of 150 metres. Headline intercepts of 92.5 metres at 0.53% copper from 3.5 metres and 83 metres at 0.57% copper from 95 metres support the continuity of near-surface mineralization for potential heap leach extraction. The company has also defined three geo-metallurgical domains and commenced test work on a 2,900 kilogram representative sample at SGS Laboratories, aimed at validating copper recovery across distinct material types for the pre-feasibility study.

In parallel, Fitzroy is advancing a proposed heap-leach joint venture with Pucobre, leveraging its existing SX-EW plant, with 800 tonnes per month capacity, as a potential low-capital production pathway. Definition drilling is expected to conclude in May, after which one rig will be reallocated to a minimum 8,000 metre Phase 3 program testing ANT-defined sulphide targets, while the second shifts to geotechnical and pit-constrained drilling.

Constraining Uncertainty: The Geo-Metallurgical Framework

Fitzroy has classified the Buen Retiro deposit into 3 geo-metallurgical domains, each reflecting a distinct mineralogical character and expected leaching response. Rather than applying a single blended treatment strategy across the entire oxide envelope, the framework allows for differentiated processing conditions, a step that directly validates the extraction assumptions before they are locked into the pre-feasibility study (PFS).

The Higher-Grade Oxide Domain, at or above approximately 0.5% copper, is expected to respond favourably to enhanced leaching. The Lower-Grade Oxide Domain, covering 0.1% to approximately 0.5% copper, is suited to shorter leach cycles. The Higher-Grade Mixed Supergene Transition Domain, which contains native copper, cuprite, and chalcocite, will be evaluated separately due to differing oxidation requirements and potential chloride-assisted leaching responses.

Test work currently underway at SGS Laboratories in Quilicura, Santiago, will evaluate mineralogy, alteration intensity, and host lithology against copper extraction kinetics and heap performance. The program covers variability analysis, targeted testing of hydrothermal breccia and iron-rich units, permeability and mini-column leach testing, and acid consumption behaviour.

The Pucobre Joint Venture: A Low-Capital Production Pathway

The commercial logic of Buen Retiro rests on a proposed heap leach joint venture with Pucobre. Pucobre operates the Planta Biocobre SX-EW facility, which has been in continuous operation since 1992 and carries a capacity of 800 tpm. The company previously operated the historical mine at Buen Retiro and trucked ore to the plant, providing a pre-existing operational relationship for the proposed joint venture. The company describes Pucobre as a best-in-class Chilean operator.

The PFS metallurgical program is designed to validate the performance of this operational model across all 3 defined domains. Conceptual modelling suggests that domain-specific treatment conditions may deliver meaningful improvements in overall copper recovery relative to a single blended oxide treatment strategy. If confirmed through test work, would directly strengthen the economic assumptions feeding into the Pucobre joint venture structure.

President & Chief Executive Officer of Fitzroy Minerals, Merlin Marr-Johnson, outlined the strategic value of this arrangement:

“We're looking at doing a heap leach joint venture with Pucobre, who are a proven partner, and as I've mentioned, there are various infrastructure advantages. This would give us non-operated cash flow and a very, very low capital intensity. This is a low-cost operation to bring into production; we think we can do it super quickly."

The Sulphide Upside: Geological Setting

While the shallow oxide program advances execution, Fitzroy maintains that Buen Retiro holds a separate and distinct exploration case at depth. The project sits in the Punta del Cobre district alongside Candelaria and Manto Verde, and independent geological consultant Dr. Irene del Real Contreras considers that the structural setting, the geology and the mineralization seen at Buen Retiro is analogous to those of Candelaria, with minor differences.

From Analogue to Target: The ANT Survey

The new catalyst for the sulphide exploration case is the recently completed passive seismic ambient noise tomography (ANT) geophysical survey, carried out by Fleet Space Technologies across a 5 kilometre x 5 kilometre area. Data processing and interpretation are underway. The survey is specifically designed to image sulphide mineralization at depth and generate drill-ready structural targets where a major IP anomaly has already been identified open at depth below the northern area, with the sulphide trend described as open to the northeast.

Once the initial dataset has been interpreted, a higher-resolution follow-up survey will cover a central 2 kilometre x 3 kilometre area over priority targets. One drill rig will then execute a minimum 8,000-metre Phase 3 program testing these ANT-defined targets. The first time exploration drilling at Buen Retiro will be guided by a purpose-built deep sulphide targeting framework rather than surface geology alone.

What to Watch Next

Definition drilling is anticipated to be completed in May. Fitzroy will re-allocate its 2 drill rigs: one to execute a minimum 8,000 metre Phase 3 exploration program targeting sulphide mineralization and ANT targets, and the second to carry out a 2,000 metre geotechnical drilling program before being replaced by a smaller rig for definition drilling in the bottom of the historical open pit. Remaining assays from the 32-hole southwest program, including re-assayed high-grade samples that exceeded the ALS laboratory's 1% copper exploration assay limit, are expected to be released progressively. The maiden mineral resource estimate and initial economic study remain the primary milestones linking current technical execution to the Pucobre joint venture pathway.

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