VANCOUVER, Canada, June 18, 2026 – Oroco Resource Corp. (TSX-V: OCO; OTCQB: ORRCF) ("Oroco" or the "Company") is pleased to report 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.
"Our Phase 2 drilling continues to confirm a compelling copper resource at Santo Tomas with low capital intensity requirements. The results clearly support a near or at surface, low strip resource as defined in the August 2024 Technical Report. The program is focused on increasing resource certainty in the South Zone to support the mine plan and a Pre-Feasibility Study, and that is what is being delivered," stated Oroco President, Ian Graham. "The elevated grades in the area of the S018 drill pad further confirm early access development in the southwest part of the South Zone and, most notably, S031 has provided evidence of mineralization that extends beyond the inferred resource of the existing block model."
Highlights
- 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 (see May 21, 2026 news release) 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 Program Overview
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 Q2/Q3 2027.
Table 1: Phase 2 Drill Holes S025, S026, S028 and S029
| Hole |
East
(m) |
North
(m) |
Elev.
(m) |
Dip
(deg.) |
Az.
(deg.) |
Objective / Comment |
| 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 (May 21, 2026 news release), it may have drilled above the main mineralized horizon. 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) |
Table 2: Significant Assay Results**
| Hole |
From
(m) |
To
(m) |
Length
(m) |
Cu% |
Mo% |
Au ppm |
Ag ppm |
Cu Eq% |
| S025 |
37 |
121.94 |
84.94 |
0.29 |
0.005 |
0.014 |
1.65 |
0.33 |
| 131 |
221 |
90 |
0.41 |
0.022 |
0.01 |
2.38 |
0.53 |
| S026 |
42 |
90.6 |
48.6 |
0.56 |
0.015 |
0.017 |
3.12 |
0.67 |
| 93 |
152 |
59 |
0.2 |
0.026 |
0.008 |
1.44 |
0.33 |
| 280 |
303.45 |
23.45 |
0.16 |
0.013 |
0.011 |
1.56 |
0.24 |
| S028 |
44 |
88.52 |
44.52 |
0.38 |
0.013 |
0.01 |
1.83 |
0.46 |
| S029 |
27 |
85.76 |
58.76 |
0.35 |
0.009 |
0.018 |
2.22 |
0.43 |
| 87.32 |
103.33 |
16.01 |
0.29 |
0.007 |
0.007 |
1.71 |
0.35 |
* CuEq (%) = [(Cu% × Cu recovery (variable) × Cu price) + (Mo% × Mo recovery (variable) × Mo price) + (Au g/t × Au recovery (variable) × Au price) + (Ag g/t × Ag recovery (variable) × Ag price)] ÷ (Cu price × Cu recovery (variable)). Metal prices in US$/lb (Cu, Mo) and US$/oz (Au, Ag) See table 3. 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.
Copper Equivalent (CuEq) Reporting
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) |
US$5.00/lb |
US$25.75/lb |
US$4,070/oz |
US$56.50/oz |
| Actual trailing average |
US$5.05/lb |
US$25.74/lb |
US$4,070.20/oz |
US$56.40 |
Quality Assurance / Quality Control
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. Total copper, molybdenum, and silver are determined by ALS method ME-ICP61 (four-acid ICP-AES); over-limit results use ore-grade assay methods. Gold is determined by ALS method Au-AA23 (30 g fire assay with AAS finish).
Qualified Person
Andrew Ware, RM-SME, a Qualified Person as defined in NI 43-101 — Standards of Disclosure for Mineral Projects, and a senior consulting geoscientist to the Company, has reviewed and approved the technical disclosures in this news release. The Company adheres to CIM Best Practices Guidelines in conducting, documenting, and reporting exploration activities.
About Santo Tomás
Santo Tomás is an advanced-stage porphyry copper project in Choix, Sinaloa, Mexico. Oroco holds a net 87.0% interest in the 1,173-hectare Core Concessions and an 80% interest in surrounding concessions at Santo Tomás. The Project was tested by historical drilling from 1968 to 1994 and by Oroco's Phase 1 program, which totaled 48,481 metres in 76 diamond drill holes and supported the revised Mineral Resource Estimate (“MRE”) and updated PEA.
The August 2024 MRE, prepared by SRK Consulting (U.S.), Inc., outlined an Indicated Resource of 540.6 Mt at 0.33% Cu, 0.008% Mo, 0.028ppm Au and 2.1 ppm Ag and an Inferred Resource of 530.3 Mt at 0.31% Cu, 0.007% Mo, 0.023ppm Au and 1.9ppm Ag. The updated PEA, prepared by Ausenco Engineering USA South Inc., contemplates a staged open-pit operation ramping from 60,000 t/d in Year 1 to 120,000 t/d by Year 8 over a 22.6-year life of mine, generating an after-tax NPV₈% of US$1.48 billion and an after-tax IRR of 22.2%. Both studies are available at www.orocoresourcecorp.com and on SEDAR+ at www.sedarplus.ca. The PEA is preliminary in nature; see "Cautionary Note" below.
About Oroco Resource Corp.
Oroco Resource Corp. is a Vancouver-based mineral exploration and development company advancing the Santo Tomás copper project in Sinaloa, Mexico.
For further information:
Ian Graham, President
Oroco Resource Corp.
Tel: 604-688-6200 | info@orocoresourcecorp.com | www.orocoresourcecorp.com
Cautionary Note Regarding Forward-Looking Information
This news release contains forward-looking information within the meaning of applicable Canadian securities legislation, including statements regarding: the Phase 2 drilling program and its objectives; the consistency of drilling results with the 2024 Technical Report block model; the anticipated advancement of the Santo Tomás Project toward a Pre-Feasibility Study and its targeted release in Q2/Q3 2027; planned and ongoing drilling, access and pad development; pending assays and the anticipated release of additional drilling data; the Company’s intention to update VRIFY with additional drill results; and the anticipated conversion of Inferred resources to the Indicated category. Forward-looking information is based on management’s current expectations and assumptions, including assumptions regarding continued access to the project, contractor availability, assay laboratory turnaround times, geological continuity and commodity prices. Such information is subject to known and unknown risks, uncertainties, and other factors that may cause actual results to differ materially from those expressed or implied, including drilling results, geological and resource estimation uncertainty, commodity price fluctuations, regulatory and permitting risks, and general economic conditions. A Preliminary Economic Assessment is preliminary in nature, includes Inferred Mineral Resources considered too speculative geologically to be categorized as Mineral Reserves, and there is no certainty that results of the PEA will be realized. Readers are cautioned not to place undue reliance on forward-looking information. The Company does not undertake to update forward-looking information, except as required by applicable securities law.
Neither the TSX Venture Exchange nor its Regulation Services Provider accepts responsibility for the adequacy or accuracy of this news release.
