Announcement • Jun 18
Oroco Resource Corp. Reports Phase 2 Drilling Results At Santo Tomás Copper Project
Oroco Resource Corp. reported the second set of assay results from its Phase 2 resource drilling program focused on the South Zone at its Santo Tomás copper project, Choix, Sinaloa, Mexico. Results are reported for drill holes S025, S026, S028 and S029 and are consistent with the 2024 Technical Report block model in the areas tested. Hole S025, a near-vertical hole collared on the same pad as S024, returned intervals consistent with the August 2024 Preliminary Economic Assessment block model (the “PEA Block Model”) and suggests stronger and thicker mineralization than was intersected in S024, including 84.94m at 0.29% Cu /0.33% CuEq and 90m at 0.41% Cu /0.53% CuEq. Hole S026 was drilled SSW from the same pad as S018 and returned 48.6m at 0.56% Cu /0.67% CuEq, 59m at 0.2% Cu /0.33% CuEq and 23.45m at 0.16% Cu /0.24% CuEq. The higher-grade material was intersected in the shallower parts of the hole. Hole S028 was drilled WSW from the same pad as S026 and tested the western limits of South Zone mineralization against the PEA Block Model, returning 44.52m at 0.38% Cu /0.46% CuEQ. Hole S029 is located 700m NNW of holes S026 and S028. The hole was drilled for infill purposes and intersected mineralization from the shallow alluvium-bedrock contact, including 58.76m at 0.35% Cu /0.43% CuEq and 16.01 m at 0.29% Cu /0.35% CuEq, reflecting very near surface mineralization and reducing strip in this area compared to the block model. Hole S031, which was drilled to the west off the same pad as hole 29, extended visual mineralization beyond the inferred resource in the PEA Block Model (assays pending). The Company is awaiting soluble copper assays for Hole S027 intercepts that returned oxide copper mineralization, and will be reported once these are received and pass QA/QC review. Soluble copper assays for oxide copper intercepts in additional holes, including drill holes S030 and S032, may also affect the sequencing of the periodic release of drilling data. The Company has mobilized a third rig to the project site. Twenty-two (22) drill holes totaling 6,709 m of the Phase 2 program have been completed, and access and pad development for the ongoing program are being accelerated. Phase 2 is designed primarily to convert Inferred resources to the Indicated resource classification in the South Zone and to collect geotechnical, hydrogeological, and additional metallurgical data required for Pre-Feasibility Study (“PFS”) level mine-planning. Drilling is also planned in the pillar area between the North and South Zones and along the southeastern edge of the North Zone pit shell. The PFS is targeted for release in Second Quarter/Third Quarter 2027. Table 1: Phase 2 Drill Holes S025, S026, S028 and S029. S025 778,914 2,975,038 677 -85 280 Same pad as S024. Infill drilling for block model support. Higher molybdenum grades in the deeper interval. Results consistent with PEA Block Model. S026 778,867 2,974,901 674 -60 190 Drilled southwards off same pad as S018. Tested western limits of the current PEA pit shell. Notably higher Au grades near the top of the hole. Ended in lower grade mineralization, but above the 0.15% Cu cut off. S028 778,867 2,974,901 674 -55 245 Drilled southwestwards off the same pad as S018. As with S024, it may have drilled above the main mineralized ho rizon. Ended with elevated Cu and Mo values suggesting deeper westward mineralization. S029 778,626 2,975,562 589 -55 95 Infill hole testing western limits: largely consistent with the PEA Block Model. S031, drilled to the west from same pad, intersected visual mineralization outside of the current PEA Block Model (assays pending). Metal recoveries are grade based by individual assay in the reported intervals and vary accordingly. In these intervals Cu recovery ranges from 82-89%, Mo 58-60%, Au 30-85% and Ag 35-67%. Au and Ag recoveries are dependent on Cu and Sulphur grades. Significant Intervals comprise intervals = 10m of = 0.15% Cu, but may include assay intervals of = 4m of = 0.05% Cu. This continues the practice of significant interval reporting applied during Phase 1, including News Releases and the August 2024 PEA. All intervals are down hole drill core lengths. True widths will be confirmed when Phase 2 results are incorporated into the updated geological and resource models. Where holes are drilled approximately perpendicular to the interpreted structural attitude of the mineralization, core intervals are expected to approximate true thickness. CuEq grades in this release are calculated using the variable metal recovery curves from Chapter 13 of the Company’s August 2024 Technical Report (“Santo Tomás Copper Project, Sinaloa, Mexico — Technical Report on a Preliminary Economic Assessment” (the “PEA”), filed on SEDAR+ August 2024) and the metal price deck in Table 3, reflecting 12-month trailing average prices to April 30, 2026. This price deck differs from that used in the PEA. Copper equivalent grades in this release are not directly comparable to CuEq grades reported in the Company’s 2024 Indicated and Inferred Resource Summary Table or in earlier drill-result news releases prior to 2024, which used different metal price assumptions and CuEq methodologies. The Company has recalculated the significant-intercept database for the full drill-hole dataset using the updated CuEq calculation: the historical drilling results and the results for holes S022 to S024 have been updated in the VRIFY drill-hole viewer and are available at VRIFY and via the Company’s website. Results from this news release will be reflected in VRIFY in due course. Table 3: Metal Prices Used for Phase 2 CuEq Calculations. Metal Cu Mo Au Ag. Price (rounded) USD 5.00/lb USD 25.75/lb USD 4,070/oz USD 56.50/oz. Actual trailing average USD 5.05/lb USD 25.74/lb USD 4,070.20/oz USD 56.40. Historical drilling data used in the current exploration program and resource estimate were subject to the data verification procedures described in the Company’s current Technical Report. Drill collar locations are verified by differential GPS with checks against LiDAR data. Geological logging, core sampling, sample preparation, analysis, and chain of custody are governed by QA/QC protocols that include the insertion of certified reference standards, blanks, and duplicates. Samples are submitted to ALS Chemex (Hermosillo, Mexico) for sample preparation; pulps are sent to ALS Canada Ltd. (Vancouver) for analysis.