Oroco Intersects 228 m of 0.49% CuEq and 212 m of 0.44% CuEq at Santo Tomás
Oroco Intersects 228 m of 0.49% CuEq and 212 m of 0.44% CuEq at Santo Tomás
VANCOUVER, BC, May 21, 2026 – Oroco Resource Corp. (TSX-V: OCO; OTCQB: ORRCF)
("Oroco" or the "Company") is pleased to report the initial 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 available for drill holes S022, S023, and S024.
Highlights:
• S022: 228.55 m at 0.38% Cu / 0.49% CuEq, including 64.86 m at 0.53% Cu / 0.69% CuEq.
• S023: 212.33 m at 0.34% Cu / 0.44% CuEq, including multiple sub-intervals of ≥0.50 Cu /
≥0.61% CuEq, plus 31.76 m at 0.50% CuEq from near-surface
• Holes S022 and S023, drilled from the same pad as Phase 1 hole S018, further confirm a
higher-grade area of South Zone mineralization
• S022 and S023 also returned elevated molybdenum grades in deeper intervals,
increasing CuEq values at depth and indicating a higher-grade core that will be tested
by four additional holes planned south and east of the S018/S022/S023 pad
• S024 intersected intermittent mineralization at the western resource margin and confirms the
current Inferred resource boundary estimated in the 2024 PEA block model
• Phase 2 program to date: 3,606 m drilled in 14 holes; 3 holes with reportable assays (this
release) and 4 holes at the assay laboratory.
"These initial Phase 2 results provide increased grade and validation of the Company’s development
plan for Santo Tomás ," said Craig Dalziel, Executive Chairman . " The program is focused on
increasing the confidence level in the South Zone resource to that required for mine planning and the
completion of a positive Pre-Feasibility Study. The elevated grades returned from holes S022 and
S023 are particularly encouraging, and the Company will continue testing this area of the South
Zone."
Phase 2 Program Overview
Phase 2 is designed primarily to convert Inferred re sources to Indicated classification in the South
Zone and to collect geotechnical, hydrogeological, and 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 Hole Locations, Objectives and Comments
Hole East
(m)
North (m) Elev.
(m)
Dip Az. Objective / Comment
S022 778,867 2,974,904 674 −65° 100° Collared from the same pad as S018 to test higher-grade South
Zone mineralization; assays received show elevated Mo grades
toward the end of the hole.
S023 778,865 2,974,903 674 −45° 140° Collared from the same pad as S018 to further test the same
elevated-grade zone reflected in S018 and S022. Elevated Mo at
depth lifting the CuEq in deeper intervals.
S024 778,912 2,975,037 676 −45° 280° Collared from the same pad as S020 to test the western edge of
the resource. Assays show intermittent mineralization consistent
with and confirming the current Inferred resource limit. Not drilled
perpendicular to the intrusive or structural controls of the Santo
Tomás deposit. Reported mineralized intervals do not reflect true
widths of the reported mineralization.
Table 2: Significant Assay Results — Phase 2 Holes S022–S024
Hole From (m) To (m) Length (m) Cu (%) Mo (%) Au (ppm) Ag
(ppm)
CuEq*
(%)
S022 4.00 29.00 25.00 0.24 0.005 0.011 1.47 0.29
S022 40.15 268.70 228.55 0.38 0.017 0.026 2.00 0.49
incl. 50.60 115.46 64.86 0.53 0.023 0.053 2.17 0.69
S022 269.70 298.00 28.30 0.21 0.003 0.005 2.16 0.25
S023 18.53 50.29 31.76 0.42 0.012 0.023 2.14 0.50
incl. 35.00 50.29 15.29 0.50 0.013 0.031 2.34 0.60
S023 60.14 272.47 212.33 0.34 0.016 0.015 1.85 0.44
incl. 66.00 86.52 20.52 0.51 0.014 0.030 2.19 0.61
incl. 164.00 185.00 21.00 0.50 0.020 0.018 2.93 0.63
incl. 207.00 222.00 15.00 0.50 0.018 0.018 2.38 0.62
S023 319.00 331.00 12.00 0.27 0.040 0.028 2.58 0.51
S024† 112.00 132.00 20.00 0.20 0.003 0.007 1.33 0.22
S024† 140.00 201.28 61.28 0.25 0.011 0.008 1.88 0.32
*CuEq (%) = [(Cu% × Cu recovery × Cu price) + (Mo% × Mo recovery × Mo price) + (Au g/t × Au recovery × Au price) + (Ag
g/t × Ag recovery × Ag price)] ÷ (Cu price × Cu recovery). Metal prices in US$/lb (Cu, Mo) and US$/oz (Au, Ag) See table 3
All intervals are drill core lengths. True widths will be conf irmed 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.
† S024 was drilled to define the extent of mineralization at the west ern resource margin and is not perpendicular to the
mineralization. Intervals for S024 do not reflect true width.
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 Asse ssment”, filed on SEDAR+ August 2024) and the
metal price deck in Table 3, reflecting 12-month trailing average prices to April 30, 2026.
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, which used different metal price assumptions and CuEq methodologies. The Company
intends to recalculate the significant-intercept database for the full drill-hole dataset using the updated
CuEq calculation and make those results available on the Company’s website 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 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 geoscient ist 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 88.5% 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 Preliminary Economic Assessment (“PEA”)
filed in August 2024.
The August 2024 MRE, prepared by SRK Consulting (U.S.), Inc., outlined an Indicated Resource of
540.6 Mt and an Inferred Resource of 530.3 Mt across the North and South Zones. The PEA, while
preliminary in nature, was prepared by Ausenco Engineering USA South Inc., and contemplates a
staged open-pit operation ramping from 60,000 t/d in Year 1 to 120,000 t/d by Year 8 within 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%.
The study, based on US$4.00 Cu/lb, is available at www.orocoresourcecorp.com and on SEDAR+ at
www.sedarplus.ca. 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:
Craig Dalziel, Executive Chairman
Oroco Resource Corp.
Tel: 604-688-6200 | [email protected] | 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 anticipated advancement of the Santo
Tomás Project toward a Pre-Feasibility Study and its anticipated release in Q2/Q3 2027; planned follow-up drill holes to test
elevated-grade zones identified in S022 and S023; the Company’ s intention to recalculate and publish its historical drill
intercept database using the updated Cu Eq methodology; and the antic ipated 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,
and commodity prices. Such information is subject to know n 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, r egulatory 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-look ing 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.