Marimaca Copper Corp. announced an updated Mineral Resource Estimate ("MRE") for the Marimaca Oxide Deposit located in the Antofagasta region of northern Chile. The 2023 MRE incorporates 28,374m of new drilling data completed since the 2022 MRE released in October 2022. The MOD database now consists of 139,164m of drilling completed since discovery in 2016. New drilling data captured following the 2022 MRE was largely targeted at conversion of Inferred Resources to the Measured and Indicated categories. The 2023 MRE was prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") Definition Standards and National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101"). The 2023 MRE was completed by independent consultants NCL Ingeniería y Construcción SpA ("NCL") and verified by Luis Oviedo of NCL, a qualified person and independent of Marimaca (within the meaning of such terms under NI 43-101). The 2023 MRE incorporates 139,164m of drilling across 554 drill holes completed between 2016 and 2022 and is reported with an effective date of May 17, 2023. The Whittle Optimisations were run using the same operating cost parameters as the 2022 MRE and a USD 4.00/lb copper price assumption. Marimaca has completed 5 phases of extensive metallurgical test work at Marimaca. A 6th phase of metallurgical testing is
underway which is expected to define the optimized process design flowsheet ahead of the planned DFS. Results from Phase 5 were announced on June 15, 2022 following a rigorous program including full-scale column testing, mini-column testing, container-leach testing, sulfation tests, acid sensitivity testing, Iso-pH testing, and head characterization for heap leach and run-of-mine ("ROM") samples. In-line with results from Phases 1-4, Phase 5 recoveries in the column and bottle roll tests generally exceeded the solubility ratio (CuS/CuT) and leaching potential of the samples, indicating a potentially larger proportion of total copper will be recovered in industrial-scale operations. The leaching potential of copper ores is defined as acid soluble copper (CuS) plus cyanide soluble copper (CuCN) divided by total copper (CuT). The acid solubility ratio (CuS/CuT) for copper oxides such as atacamite, brochantite and chrysocolla, which dissolve quickly when exposed to acid, is a good predictor of leachability. However, where the mineralization has several copper bearing minerals with different dissolution characteristics under these leaching conditions (such as Marimaca's black oxide (wad) component), the copper acid solubility ratio may materially underestimate the acid leaching potential for heap leach operations, especially where soluble copper sulphides such as chalcocite, covellite and bornite are present. structures and splays. Higher grade green oxide mineralization (brochantite, atacamite, chrysocolla) dominates the core of the deposit and is located near-surface. High grade zones of oxides, mixed and enriched mineralization extend at depth beneath the green oxide zones. The MOD is exposed at surface which is expected to drive a low strip ratio during the mine's potential
operational phase. Exploration for sulphide mineralization down-dip of the MOD to the east is ongoing and results will be released when available. The MOD oxide potential remains open to the east and southeast and further exploration may be planned in due course. Satellite oxide discoveries made in 2021 (Mercedes, Cindy, Roble) have not received sufficient drilling to be included in the 2023 MRE. Grade estimates were completed using ordinary kriging with nominal block size measuring 5m by 5m by 5m. Resources have been classified by their proximity to sample locations and number of drill holes and samples within different search ellipsoids, and are reported according to the CIM Definition Standards for Mineral Resources and Mineral Reserves and NI 43-101. The technical and economical parameters used for the 2023 MRE are identical to the 2022 MRE and were informed by the 2020
Preliminary Economic Assessment ("PEA") assumptions. Although the PEA no longer reflects the current economic potential of the project and should be seen as historical in nature and should not be relied upon, the 2020 PEA cost assumptions are still considered to be the most relevant cost assumptions for the 2023 MRE at this stage.