Oroco Drills 234.6 metres of 0.52% CuEq at Santo Tomás
Updated copper-equivalent grades are not directly comparable with the 2024 resource summary or drill-result releases issued before 2024.
Sentiment and the balance of points
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Rhea-AI Summary
Oroco Resource (ORRCF) reported a 234.6-metre copper-equivalent intercept in the fifth batch of Phase 2 drilling results at Santo Tomás in Mexico. Hole S045 returned 0.43% copper and 0.52% copper equivalent, a recovery- and price-adjusted measure of combined metal grades, from 174.1 metres. The batch covers ten holes. S049 returned 86.1 metres at 0.60% copper equivalent; S053 returned 84.2 metres at 0.58%.
Phase 2 has completed 50 holes totaling 15,263.2 metres, with three rigs operating. South Zone resource drilling is complete; Pillar Zone and geotechnical drilling continue. S051 returned 102.3 metres at 0.46% copper near the western margin. S056 intersected mineralization shallower than modelled. No processing route is planned for S050's carbonate-hosted mineralization. Some assays remain pending, and resource additions require further modelling. All intervals are downhole lengths; true widths remain unconfirmed.
Positive
- Minor pointS045 returned 234.6 m at 0.43% Cu and 0.52% CuEq from 174.1 m.
- Minor pointS046 returned 128.0 m at 0.36% Cu and 0.48% CuEq from surface.
- Minor pointS046 intersected below-pit mineralization: 26.0 m at 0.43% CuEq and 14.1 m at 0.30% CuEq.
- Minor pointS049 returned 86.1 m at 0.51% Cu and 0.60% CuEq from 85.5 m.
- Minor pointS053 returned 84.2 m at 0.50% Cu and 0.58% CuEq from 159.6 m.
7 minor points
- Minor pointS051 returned 102.3 m at 0.46% Cu from 35.0 m, near the base of overburden.
- Minor pointS056 returned 95.4 m at 0.29% Cu and 0.38% CuEq from 40.6 m, shallower than modelled.
- Minor pointS050 returned 6.0 m with 4.18% Zn, 1.71% Pb, 75 g/t Ag, 0.35 g/t Au and 0.48% Cu.
- Minor pointSouth Zone resource drilling is complete; Phase 2 has completed 50 holes totaling 15,263.2 m.
- Minor pointPillar Zone drilling continues, and geotechnical drilling has commenced to support mine-planning work.
- Minor point. Forward-looking: it has not happened yet and may not happen.Phase 2 aims to evaluate potential resource-category upgrades and collect data for pre-feasibility-level mine planning.
- Minor point. Forward-looking: it has not happened yet and may not happen.Oroco is designing follow-up 3D DCIP geophysics at Vainilla after completing a 707 line-kilometre magnetic survey.
Negative
- Minor point. Forward-looking: it has not happened yet and may not happen.Potential below-pit resource additions require updated modelling, pit optimization, stripping constraints and reasonable prospects of eventual economic extraction.
- Minor point. Forward-looking: it has not happened yet and may not happen.Potential western pit extension and lower stripping requirements remain subject to updated resource modelling and mine planning.
- Minor pointS050 carbonate-hosted mineralization has no planned processing route; its suggested non-sulphide component requires mineralogical confirmation.
- Minor pointS047 confirmed weakening mineralization toward the east; further drilling is warranted north and east.
- Minor pointS050 and S055 returned sporadic lower-grade copper assays in the northeastern low-grade and waste area.
3 minor points
- Minor pointS052, S052A and S054 assays remain pending re-assay and review; some western-margin assays also remain pending.
- Minor pointS066 visually identified copper mineralization has assays pending; visual observations do not establish grade or economic viability.
- Minor pointUpdated CuEq grades are not directly comparable with the 2024 resource summary or pre-2024 drill-result releases.
News Explained
These reported copper-equivalent grades use variable-recovery curves and a price deck based on trailing average prices through
AI-generated analysis. How Rhea-AI works. Not financial advice.
Vancouver, British Columbia--(Newsfile Corp. - October 8, 2026) - Oroco Resource Corp. (TSXV: OCO) (OTCQB: ORRCF) ("Oroco" or the "Company") is pleased to report the fifth batch of assay results from its Phase 2 resource drilling program in the South Zone of the Santo Tomás copper project in Choix, Sinaloa, Mexico. The assayed results cover ten drill holes, including S045 that delivered a 234.6-metre interval of
Phase 2 has now completed 50 holes in the South and Pillar Zones, with 15,263.2 m drilled and three rigs operating at Santo Tomás. South Zone resource drilling is now complete, while Pillar Zone and geotechnical work continue. The Company has previously reported Phase 2 results through hole S044. Drill-hole locations are shown in Figure 1.
Highlights
- S045: 234.6 m at
0.43% Cu (0.52% CuEq) from 174.1 m, a broad central South Zone intercept. - S046: 128.0 m at
0.36% Cu (0.48% CuEq) from surface, with additional mineralization below the 2024 Preliminary Economic Analysis ("PEA") pit. - S049: 86.1 m at
0.51% Cu (0.60% CuEq) from 85.5 m, reinforcing the southern higher-grade zone. - S050: 6.0 m of carbonate-hosted mineralization at
4.18% Zn,1.71% Pb, 75 g/t Ag, 0.35 g/t Au and0.48% Cu from 36.0 m. - S051: 102.3 m at
0.46% Cu from 35.0 m, beginning near the base of overburden on the western margin. - S053: 84.2 m at
0.50% Cu (0.58% CuEq) from 159.6 m, confirming higher-grade mineralization in the south. - S056: 95.4 m at
0.29% Cu (0.38% CuEq) from 40.6 m, shallower than modelled at the northwestern pit margin.
All intervals are downhole lengths; true widths remain to be confirmed. See Table 2 and the accompanying technical notes. No processing route is currently planned for the S050 carbonate-hosted mineralization.
"These results continue to strengthen our optimism for an expanded resource model at Santo Tomás together with increased certainty as to the grade continuity and overall project viability," stated Oroco's CEO, Charles Cryer. "With South Zone resource drilling now complete, we look forward to seeing how these very positive overall results influence the valuation presented in the project's next economic assessment."
Southern Quarter of the South Pit
Drill holes S046, S048, S049 and S053 were among the final holes in the southern quarter of the South Pit. Their results support the current PEA block model and the area of higher grades centred around S018 (Phase 1); assays for S054 remain pending. S046 also returned 26.0 m at
Western Edge of the South Pit
Drilling along the underexplored western extents of the block model and PEA pit design continued with S051 and S056. S051 results, in conjunction with Cu-Ox outcropping mineralization to the west of the hole, suggest the pit limit may extend in that direction. The higher-grade interval begins essentially at the base of overburden. This interval correlates well with historical drill hole STD-37 to the east. S056, a Pillar Zone hole north of previously reported S033 and S034, was drilled towards the ESE. Its mineralization reinforces the interpretation that the main mineralized horizon flattens to the west. This geometry may allow a shallower pit locally and lower stripping requirements, subject to updated resource modelling and mine planning. Visual observations in other western-margin holes are consistent with this interpretation, but assays remain pending for some of those holes.
North-Central Area of the South Pit and Eastern South Pit Limits
Drill hole S045 was collared in the central portion of the South Pit as an infill hole and supported the grades presented in the block model in that area. Hole S047 represents the eastern-most hole in the central portion of the south pit and confirmed the up-dip extension of weakening mineralization towards the east. It highlighted that historical drill hole STE-57 may have stopped short of the mineralized zone at depth. Further drilling is warranted to the north and east. A planned geotechnical hole will cover the area to the south.
Northeastern Low-Grade and Waste Area of the South Pit
Drill holes S050 and S055 were collared in the northeastern quadrant of the South Pit. Both returned sporadic lower-grade copper assays, consistent with the block model. S050 also intersected carbonate-hosted zinc-lead-silver mineralization immediately above the andesite contact: 6.0 m from 36.0 m returned
Table 1. Drill-hole locations and purpose.
| Hole | East | North | Elev. | Dip | Az. | Objective / Comment |
| (m) | (m) | (m) | (deg.) | (deg.) | ||
| S045 | 779,023 | 2,975,149 | 777.8 | -55° | 100° | Infill drill hole in the central portion of the South Pit. Results largely support the PEA Block Model ("BM") |
| S046 | 778,950 | 2,974,703 | 716.6 | -80° | 110° | A -80O hole off the most southwestern pad in the South Zone. Supports BM, with two additional mineralized intervals between 351.0 m and 401.1 m downhole below the PEA pit |
| S047 | 779,301 | 2,974,985 | 850.7 | -50° | 90° | Easterly hole in the southern half of the South Zone. Added certainty to mineralization extending in that direction. Additional holes warranted in the area |
| S048 | 778,950 | 2,974,700 | 716.8 | -55° | 235° | Drilled SW off the same pad as S046. Confirmed BM limits and current pit design, notwithstanding the deeper S046 intercepts |
| S049 | 779,053 | 2,974,761 | 744.0 | -80° | 110° | Collared SW of S018. Confirms higher grade zone recorded in S018 and supports similar results in adjacent holes |
| S050 | 778,993 | 2,975,634 | 696.4 | -45° | 110° | Collared in a zone of lower grade / waste in the PEA BM. Largely confirms BM though intersected 2 m higher-grade intercept of replacement style mineralization above the limestone-andesite contact. A high-grade interval of Cu |
| S051 | 778,789 | 2,975,504 | 645.2 | -50° | 255° | Drilled westwards south of holes S029, S030 and S031. As with those holes, the drill intersected near surface mineralization near the edge of the BM |
| S053 | 779,054 | 2,974,760 | 744.0 | -55° | 120° | Infill drill-hole off same pad as S049 and S054. Confirmed BM and PEA Pit Limits |
| S055 | 778,996 | 2,975,735 | 711.3 | -65° | 110° | Collared north of S050 in the low grade / waste zone. A lower tenor zone of replacement mineralization was observed as in Hole S050 |
| S056 | 778,710 | 2,975,860 | 620.9 | -60° | 110° | Pillar Zone hole on northwestern edge of South Pit. Mineralization closer to surface than modelled in BM |
Assays for S052, S052A and S054 remain in QA/QC for re-assay and review.
Table 2: Significant Copper Assay Intercepts**
| Hole | From (m) | To (m) | Interval (m) | CuT % | CuSol % | Mo % | Au ppm | Ag ppm | CuEq* % |
| S045 | 174.1 | 408.7 | 234.6 | 0.43 | - | 0.008 | 0.033 | 2.39 | 0.52 |
| 411.3 | 434.5 | 23.2 | 0.25 | - | 0.003 | 0.022 | 1.16 | 0.28 | |
| S046 | 0 | 128 | 128 | 0.36 | - | 0.019 | 0.016 | 2.60 | 0.48 |
| 351 | 377 | 26 | 0.31 | - | 0.020 | 0.015 | 2.35 | 0.43 | |
| 387 | 401.1 | 14.1 | 0.23 | - | 0.006 | 0.017 | 2.48 | 0.30 | |
| S047 | 41 | 59 | 18 | 0.19 | - | 0.006 | 0.012 | 1.51 | 0.23 |
| 151 | 162 | 11 | 0.19 | - | 0.003 | 0.022 | 2.56 | 0.25 | |
| 253.3 | 312 | 58.7 | 0.24 | - | 0.007 | 0.022 | 1.13 | 0.29 | |
| S048 | 21 | 91 | 70 | 0.33 | - | 0.021 | 0.012 | 2.17 | 0.45 |
| 106 | 138.8 | 32.8 | 0.35 | - | 0.015 | 0.010 | 2.01 | 0.44 | |
| 140.6 | 179.1 | 38.5 | 0.22 | - | 0.013 | 0.008 | 1.07 | 0.29 | |
| S049 | 13.7 | 24 | 10.3 | 0.24 | - | 0.003 | 0.010 | 1.38 | 0.26 |
| 30.8 | 82.7 | 51.9 | 0.20 | - | 0.005 | 0.013 | 1.23 | 0.24 | |
| 85.5 | 171.6 | 86.1 | 0.51 | - | 0.007 | 0.029 | 2.81 | 0.60 | |
| 172.3 | 304 | 131.7 | 0.37 | - | 0.015 | 0.013 | 1.79 | 0.46 | |
| 335 | 352.8 | 17.8 | 0.26 | - | 0.005 | 0.009 | 1.81 | 0.31 | |
| 354.5 | 369 | 14.5 | 0.29 | - | 0.011 | 0.022 | 1.99 | 0.38 | |
| S051 | 35 | 137.3 | 102.3 | 0.46 | 0.04 | 0.001 | 0.081 | 3.32 | - |
| S053 | 15.2 | 158.6 | 143.4 | 0.31 | - | 0.008 | 0.015 | 1.80 | 0.36 |
| 159.6 | 243.8 | 84.2 | 0.50 | - | 0.006 | 0.021 | 2.97 | 0.58 | |
| 248.1 | 291.9 | 43.8 | 0.29 | - | 0.013 | 0.014 | 2.07 | 0.37 | |
| 294.3 | 421 | 126.7 | 0.30 | - | 0.016 | 0.014 | 2.67 | 0.41 | |
| S056 | 40.6 | 136 | 95.4 | 0.29 | - | 0.013 | 0.021 | 2.17 | 0.38 |
* 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 are stated in US$/lb for Cu and Mo and US$/oz for Au and Ag; see Table 3. Metal recoveries are grade-based for each assay within the reported intervals and vary accordingly. Across these intervals, Cu recovery ranges from
** Significant intervals are at least 10 m long and comprise samples that grade at least
CuT is total copper, determined by ALS method ME-ICP61 using a four-acid digest.
CuSol is soluble copper, determined by ALS method Cu-AA05 using a sulphuric-acid leach on intervals exhibiting oxidation. Soluble-copper assays are included for S051 in this release and have been reported for relevant holes previously.
All intervals are downhole core lengths. True widths will be confirmed when the Phase 2 results are incorporated into updated geological and resource models. Where drill holes are oriented approximately perpendicular to the interpreted attitude of the mineralization, the reported core intervals are expected to approximate true thickness.
Figure 1: Phase 2 drill holes S045 to S056 in relation to prior drilling and completed Phase 2 holes awaiting assays. Results for S052, S052A and S054 remain pending.
To view an enhanced version of this graphic, please visit:
https://images.newsfilecorp.com/files/12130/318054_1359666bf49c09df_001full.jpg
Phase 2 Program and Project Context Update
Phase 2 is designed primarily to provide the drilling density and technical data needed to evaluate the potential conversion of Inferred Mineral Resources to the Indicated category in the South Zone. The program is also collecting geotechnical, hydrogeological and metallurgical data to support pre-feasibility study ("PFS")-level mine planning.
The South Zone resource-drilling component is complete, with drilling continuing in the Pillar Zone between the North and South Zones. Geotechnical drilling has commenced. Where feasible, the geotechnical holes will serve as resource infill drilling. Drill holes S067 (423 m) and S068 (438 m) were recently completed, while GT003 is in progress at 80 m in the South Zone. To date, 12,830.1 m of core has been sampled during Phase 2, through hole S063, representing 8,512 samples: 7,063 core samples and 1,449 QA/QC samples.
Additional Updates
Mexico permitting momentum: ProMinería, citing figures supplied by Mexico's Ministry of Economy to BNamericas, reported that approximately
Vainilla geophysics program in preparation: Following completion of a 707 line-kilometre drone magnetic survey over ~3,114 hectares, the Company is designing a follow-up 3D DCIP geophysics program over priority areas at the Vainilla property, which is located approximately 17 km south of the Santo Tomás South Zone.
Copper Equivalent (CuEq) Reporting
CuEq grades in this release are calculated using the variable metal-recovery curves in 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+ in August 2024, and the metal-price deck in Table 3, which reflects 12-month trailing average prices to April 30, 2026. This price deck differs from the one used in the PEA.
The CuEq grades in this release are therefore not directly comparable with CuEq grades reported in the Company's 2024 Indicated and Inferred Mineral Resource summary or in drill-result news releases issued before 2024, which used different metal-price assumptions and/or CuEq methodologies. The Company has recalculated the significant-intercept database for the full drill-hole dataset using the updated CuEq methodology. Historical drilling results and results for holes S022 through S044 have been updated in the VRIFY drill-hole viewer and are available through VRIFY and the Company's website. CuEq values are not calculated for intervals with soluble-copper assays (please refer to News Release of August 6, 2026 and this release).
Table 3: Metal Prices Used for Phase 2 CuEq Calculations
| Metal | Cu | Mo | Au | Ag |
| Price (rounded) | US | US | US | US |
| Actual trailing average | US | US | US | US |
Quality Assurance / Quality Control
Both the historical drilling data used in the current exploration program and Mineral Resource Estimate and the Phase 2 drilling data reported in this news release were subject to the data-verification procedures described in the Company’s current technical report. Drill-collar locations are verified by differential GPS and checked against LiDAR data. Geological logging, core sampling, sample preparation, analysis, and chain of custody are governed by QA/QC protocols that include certified reference materials, blanks and duplicates. Samples are prepared by ALS Chemex in Hermosillo, Mexico, and pulps are sent to ALS Canada Ltd. in Vancouver for analysis. Total copper, molybdenum, and silver are determined by ALS method ME-ICP61 (four-acid ICP-AES). Over-limit copper (>10,000ppm) is re-assayed using Cu-OG62, soluble copper is determined by Cu-AA05, and gold is determined by Au-AA23 (30 g fire assay with an AAS finish). Over limit Ag (>100 ppm), Zn (>10,000 ppm) and Pb (>10,000 ppm) are determined by ALS using analytical techniques Ag-OG62, Zn-OG62 and Pb-OG62 respectively.
Qualified Person
Andrew Ware, RM-SME, a Qualified Person as defined by National Instrument 43-101 - Standards of Disclosure for Mineral Projects and a senior consulting geoscientist to the Company, has reviewed and approved the scientific and technical information in this news release. The Company follows CIM Best Practices Guidelines in conducting, documenting and reporting its exploration activities.
About Santo Tomás
Santo Tomás is an advanced-stage porphyry copper project in Choix, Sinaloa, Mexico. Oroco holds a net
Santo Tomás is included among the strategic investment projects under Plan México and has been recognized as the primary mining development within the Topolobampo Economic Hub, with federal and state support for permitting. Santo Tomás is the only mining project included in Plan México.
The August 2024 MRE, prepared by SRK Consulting (U.S.), Inc., outlined an Indicated Resource of 540.6 Mt at
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:
Charles Cryer, CEO
Oroco Resource Corp.
Tel: 604-688-6200 | info@orocoresourcecorp.com | www.orocoresourcecorp.com
Cautionary Note Regarding Mineral Resource Disclosure and Forward-Looking Information
This news release includes disclosure of the PEA and Mineral Resources. The PEA is preliminary in nature, includes Inferred Mineral Resources considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as Mineral Reserves, and there is no certainty that the PEA will be realized. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
The geological interpretations and potential resource or mine-planning opportunities discussed in this release are preliminary. Visual observations are not a substitute for laboratory assays and do not establish grade, continuity, Mineral Resources or economic viability. These drilling results do not establish a resource addition, category conversion, processing route for the S050 carbonate-hosted mineralization, reduction in strip ratio or improvement in project economics. Information in this release concerning Plan México, SEMARNAT permitting statistics and other companies' projects is derived from public sources and has not been independently verified by the Company; permitting outcomes for other projects are not necessarily indicative of permitting outcomes for Santo Tomás.
This release contains "forward-looking information" within the meaning of applicable Canadian securities laws, including statements and interpretations concerning: the objectives, continuation and completion of the Phase 2 drilling program; the updated Mineral Resource Estimate targeted for Q1 2027 and advancement of pre-feasibility study ("PFS") work; the potential conversion of Inferred Mineral Resources to the Indicated category; mineralization below or beyond the current PEA pit limits, along the western margin and in the Pillar Zone, and the potential for additional Mineral Resources; possible changes to pit geometry and stripping requirements; the expectation that certain downhole intervals may approximate true thickness; further evaluation of the S050 carbonate-hosted mineralization; further drilling to the north and east of S047 and planned geotechnical drilling; the use of geotechnical holes as resource infill; the collection and use of geotechnical, hydrogeological and metallurgical data in PFS-level mine planning; the potential effect of metal prices on project economics in the PFS; and the Mexican permitting environment and the project's status under Plan México. Such information is based on management's expectations and assumptions regarding assay and technical-data accuracy; geological continuity and model reliability; the representativeness of metallurgical; sufficient funding and continued project access; the availability and performance of personnel, contractors, drill rigs, laboratories and other services; the absence of material operational, regulatory, security, environmental or community disruption; prevailing and long-term commodity prices, metallurgical recoveries, capital and operating costs and other economic assumptions to be used in the PFS; and the receipt of required permits and approvals on acceptable terms.
Forward-looking information is subject to risks and uncertainties that may cause actual results to differ materially, including that assays, QA/QC review, future drilling, modelling or technical studies may not confirm current interpretations, grades, widths, continuity, potential resource additions or resource-category conversion; that pit limits may contract as well as expand; that metallurgical and geotechnical data may not be representative of the broader deposit or support anticipated mine-planning outcomes; delays or changes in funding, drilling, assay delivery, modelling, geophysical programs, permitting or PFS schedules; changes in metal prices, recoveries, costs or other assumptions including that higher metal prices may be offset by cost escalation and may not result in improved PFS economics; and access, title, regulatory, environmental, community, social, security and political risks, together with the general risks of mineral exploration and development. Permitting outcomes for other projects, and the project's inclusion in government initiatives, do not assure receipt of permits or a development decision for Santo Tomás. The Company believes the assumptions are reasonable as of the date of this release, but there can be no assurance that the forward-looking information will prove accurate. Readers are cautioned not to place undue reliance on it. Except as required by applicable securities laws, the Company undertakes no obligation to update or revise forward-looking information.
Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news release.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/318054
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
What did Oroco's S045 drill hole return at Santo Tomás?
S045 returned 234.6 metres at 0.43% copper and 0.52% copper equivalent, beginning at 174.1 metres downhole. It was an infill hole in the central South Pit and supported the grades in the block model. The interval is a downhole length, with true width still to be confirmed.
Is Oroco's South Zone resource drilling at Santo Tomás complete?
South Zone resource drilling is complete, while Pillar Zone and geotechnical work continue. Phase 2 has completed 50 holes totaling 15,263.2 metres, with three rigs operating at Santo Tomás.
How does Oroco calculate copper-equivalent grades for the Santo Tomás drilling results?
Oroco calculates copper-equivalent grades using variable metal-recovery curves from its August 2024 technical report and updated metal prices reflecting 12-month trailing averages to April 30, 2026. Rounded calculation prices are US$5.00/lb copper, US$25.75/lb molybdenum, US$4,070/oz gold and US$56.50/oz silver. Copper-equivalent grades are not reported for intervals containing both sulphide and non-sulphide copper.
What counts as a significant copper intercept in Oroco's Santo Tomás drilling results?
Significant intervals are at least 10 metres long and comprise samples grading at least 0.15% copper, but may include individual intervals of up to 4 metres grading at least 0.05% copper. Lower-grade intervals may also be reported to show continuity; those are not themselves presented as significant intercepts.
