Oroco Continues South Zone Success
September 10th, 2026 NEWS RELEASE
OROCO CONTINUES SOUTH ZONE SUCCESS
VANCOUVER, BC, September 10 th, 2026 – Oroco Resource Corp. (TSX-V: OCO; OTCQB: ORRCF)
("Oroco" or the "Company") is pleased to report the fourth batch of assay results from its Phase 2 resource
drilling program in the South Zone of the Santo Tomá s copper project in Choix, Sinaloa, Mexico. The
results cover ten drill holes, S035 through S044.
Drill-hole locations are shown on Figure 1, and collar de tails are provided in Table 1. Drill holes S061 (at
256 m), S063 (at 225 m) and S064 (at 10 m) are currently in progress in the Pillar Zone between the North
and South Zones: 42 holes of the Phase 2 program ha ve been completed including 12,649.3 m drilled. To
date, 11,431 m of core has been sampled during Ph ase 2, representing 7,543 samples of which 6,255 are
core samples and 1,288 are QA/QC samples: this count includes some samples from drill holes S057 and
S058. The Company has previously reported Phase 2 drilling for holes S022 through S034. Oroco currently
has three drill rigs operating at Santo Tomás.
Highlights
Notable Results
S035: 57.4 m grading 0.72% CuEq from 108 m.
S038 and S041 ended in mineralization approximately 200 m and 90 m, respectively, below the
current PEA pit limits.
S039: 103 m grading 0.58% CuEq from 98 m.
S040: 154 m grading 0.51% CuEq from 131 m, followed by 14 m grading 0.83% CuEq from
287 m.
S042: 369.3 m from surface grading 0.45% CuEq.
All intervals are downhole lengths. See Table 2 and the accompanying technical notes.
“These overall results provide furth er confidence in the South Zone model while also identifying
mineralization beyond the current PEA pit limits,” said Charles Cryer, CEO. “The long S042 intercept and
the extensions in S038 and S041 improve our geological understandi ng as South Zone resource drilling
nears completion and the drill rigs migrate into th e Pillar Zone. The drilling has also strengthened the
historical dataset used for future resource estimation, an important aspect of the current program.”
Southern end of the South Pit
Drill holes S037, S038 and S041 through S044 were completed in the southern quarter of the South Pit and
indicate locally higher aggregate grades than those represented in the current South Zone Inferred Mineral
Resource model. Holes S038 and S041 ended in mineralization approximately 200 m and 90 m,
respectively, below the current PEA pit limits. Any potential addition to Mineral Resources would be
subject to updated geological a nd resource modelling, pit optimization, stripping constraints and the
requirement for reasonable prospects of eventual economic extraction.
North-Central Area of the South Pit and Eastern Pit Limits
Holes S035, S036, S039 and S040 comprise infill, metallurgical and twin drilling in the north-central and
eastern portions of the South Pit. The assay results ge nerally correspond with the copper grades predicted
by the August 2024 PEA block model. The twin dr illing also provides additional multi-element data
because historical (pre-Oroco) programs did not cons istently assay all samples for molybdenum, gold and
silver, strengthening the dataset available for future geological and resource modelling.
Phase 2 Program Overview
Phase 2 is designed primarily to provide the drilling de nsity and technical data needed to evaluate the
potential conversion of Inferred Minera l 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 we ll advanced, and drilling has commenced in the Pillar
Zone between the North and South Zones.
Table 1: Phase 2 Drill Holes S035 to S044
Hole East
(m)
North
(m)
Elev.
(m)
Dip
(deg.)
Az.
(deg.)
Objective / Comment
S035 778,838 2,975,787 651 -65° 100° Northern half, central South Pit. Confirmed
mineralization tenor relative to historical hole
STD-35.
S036 779,088 2,974,949 802 -90° 0° Twin of historical hole STD-50. Copper grades
correlate well; core will also support
metallurgical test work.
S037 779,260 2,974,443 763 -55° 100° Southern end of the South Pit. Grades conform
with the block model and current pit limit.
S038 779,257 2,974,444 763 -65° 280° Drilled w estward from the same pad as S037.
The hole ended in mineralization approximately
200 m vertically below the current PEA pit
limit, indicating potential for mineralization
beyond the current pit shell.
S039 779,199 2,975,319 759 -55° 100° Eas t-central area of the current South Pit. Assays
correspond well with the copper grades
estimated in the block model.
S040 779,069 2,975,263 761 -55° 100° Similar objective to S039. Assays correspond
well with the copper grades estimated in the
block model.
S041 779,179 2,974,813 813 -45° 155° Tests the highe r-grade zone identified in Phase 1
hole S018 to the west. S041 ended in
mineralization approximately 90 m vertically
below the current PEA pit limit.
S042 778,951 2,974,702 717 -45° 120° Infill hole within the highe r-grade S018 area of
the South Zone; returned 369.3 m grading
0.45% CuEq.
S043 778,950 2,974,701 717 -50° 170° Defines the southern limit of mineralization
south of the S018 zone.
S044 778,950 2,974,703 717 -55° 290° Drilled fro m the same pad as S043; helps define
the western limit of mineralization in the
southwest quadrant of the current pit.
Geometallurgical Core Characterization
Oroco is utilizing Geopyörä drill-core testing technology to deve lop more comprehensive and spatially
representative geotechnical and comminution data across the Santo Tomás deposit. Testing of both
historical Phase 1 drill core and core from the current Phase 2 program will provide systematic
measurements of rock hardness, breakage characteris tics and grindability, allowing these properties to be
incorporated spatially into the PFS block model.
This work will improve predictive mill throughput estimates and the understanding of energy consumption
variability over the life of mine and inform an updated PFS mine schedule base d on an updated Mineral
Resource Estimate. The data will allow prioritization of mill feed by rock type and grade to maximize
payable metal production at the lowest cost as early as possible in the mining operations. The results will
reduce initial capital risk by better sizing process plant elements, in addition to reducing uncertainties
associated with life-of-mine metal production and financial performance.
Concurrent and historical point load testing correlates well to date with the Geopyörä data and supports the
thesis that South Zone mill feed will require reduced comminution energy relative to the estimate presented
in the August 2024 PEA.
Table 2: Significant Assay Results for Sulphide Intercepts**
Hole From
(m)
To
(m)
Interval
(m)
CuT
%
Mo
%
Au
ppm
Ag
ppm
CuEq
%*
S035 74.8 100 25.2 0.34 0.002 0.090 2.19 0.45
108 165.4 57.4 0.55 0.002 0.120 2.80 0.72
S036
92 109.4 17.4 0.32 0.011 0.010 2.22 0.40
113 299 186 0.32 0.006 0.022 1.70 0.37
307 389.3 82.3 0.30 0.007 0.018 1.75 0.37
435 451 16 0.16 0.011 0.005 1.74 0.23
S037
0 12 12 0.09 0.005 0.006 3.07 0.16
18 185 167 0.28 0.015 0.010 1.90 0.36
195.8 247.6 51.8 0.28 0.009 0.018 2.47 0.36
S038
0 33 33 0.09 0.011 0.009 2.52 0.19
70 91.8 21.8 0.34 0.008 0.012 1.24 0.39
101.4 128.2 26.8 0.37 0.011 0.011 2.62 0.45
135 190.9 55.9 0.39 0.014 0.021 1.99 0.49
198 274 76 0.27 0.039 0.014 2.09 0.47
314 329 15 0.08 0.022 0.012 0.89 0.20
337 359 22 0.08 0.012 0.007 2.50 0.18
370 399.2 29.2 0.13 0.018 0.008 1.90 0.24
S039
25 38.8 13.8 0.17 0.004 0.020 1.60 0.20
55 66 11 0.13 0.003 0.018 1.98 0.17
80 90 10 0.14 0.003 0.009 2.96 0.19
Hole From
(m)
To
(m)
Interval
(m)
CuT
%
Mo
%
Au
ppm
Ag
ppm
CuEq
%*
98 201 103 0.47 0.006 0.045 3.36 0.58
S040
131 285 154 0.42 0.011 0.024 2.66 0.51
287 301 14 0.65 0.000 0.132 3.29 0.83
307 319 12 0.30 0.003 0.036 2.08 0.36
S041 73.5 285.2 211.7 0.25 0.008 0.014 2.33 0.32
289.3 539 249.7 0.30 0.010 0.010 1.66 0.36
S042 0 369.3 369.3 0.34 0.018 0.015 2.42 0.45
370.3 393.1 22.8 0.13 0.014 0.008 1.10 0.20
S043
0 94.6 94.6 0.30 0.016 0.019 1.54 0.40
232.6 279 46.4 0.07 0.025 0.009 0.97 0.21
295 313 18 0.05 0.019 0.010 0.56 0.18
S044 0 213 213 0.26 0.017 0.010 1.66 0.36
219 229 10 0.10 0.026 0.009 0.45 0.22
* 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 82% to 89%, Mo from 50% to 60%, Au
from 30% to 85% and Ag from 35% to 67%. Au and Ag recoveries depend on copper and sulphur grades. Copper-equivalent grades
are not reported for intervals containing both sulphide and non-sul phide copper. The CuEq presented in Figure 1 is calculated
using the method described above.
** Significant intervals are at least 10 m l ong and comprise samples that grade at le ast 0.15% Cu, but may include individual
intervals of up to 4 m grading at least 0.05% Cu. Where a hole contains multiple assay intervals in reasonable downhole proximity,
lower-grade intervals are also reported to show continuity with significant intercepts and are not themselves held out as significant.
This is consistent with the significant-interval reporting conv ention used for Phase 1 news re leases and the August 2024 PEA.
Copper-equivalent grades are not reported for intervals with copper oxide assays.
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: there
are no soluble copper assays included for assays reported in this news release, but has 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 attit ude of the mineralization, the reported core intervals are expected to
approximate true thickness.
Copper Equivalent (CuEq) Reporting
CuEq grades in this release are calculated using the va riable metal-recovery curves in Chapter 13 of the
Company’s August 2024 technical report, “Santo To más 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 tr ailing 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 fo r 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).
Figure 1: Phase 2 Drill Holes S035 to S044 located in relation to prior drilling and completed Phase
2 holes awaiting assay results.
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/oz
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 anal ysis. Total copper, molybdenum a nd silver are determined by ALS
method ME-ICP61 (four-acid ICP-AES). Over-limit coppe r 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).
Qualified Person
Andrew Ware, RM-SME, a Qualifie d Person as defined by National In strument 43-101 – Standards of
Disclosure for Mineral Projects and a senior consulti ng 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, Si naloa, Mexico. Oroco holds a net
88.5% interest in the 1,173-hectare Core Concessions and an 80% interest in the surrounding concessions.
Historical drilling between 1968 and 1994, together with Oroco’s Ph ase 1 program of 48,481 m in 76
diamond drill holes, 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, 0.028 ppm Au and 2.1 ppm Ag and an Inferred Resource of 530.3 Mt at
0.31% Cu, 0.007% Mo, 0.023 ppm Au and 1.9 ppm 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:
Charles Cryer, CEO
Oroco Resource Corp.
Tel: 604-688-6200 | [email protected] | www.orocoresourcecorp.com
Cautionary Note Regarding Mineral Resource Disclosure and Forward-Looking Information
This news release includes disclosure of a Preliminary Economic Assessment (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.
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
potential conversion of Inferred Mineral Resources to the Indicated category; mineralization beyond the current PEA pit
limits and the potential for additional Mineral Resources; the expectation that certain downhole intervals may approximate
true thickness; the use of Phase 2 results in updated geological, resource and PFS-level mine-planning work; the development
and expected benefits of the Geometallurgical model, incl uding its anticipated use in optimizing mine scheduling, process
design, energy requirements and plant throughput; drilling in the Pillar Zone; and future VRIFY updates. Such information
is based on management’s expectations and assumptions regarding assay and technical-data accuracy; geological continuity
and model reliability; the representativeness of geotechnical and comminution test work; continued project access; the
availability and performance of personnel, contractors, drill ri gs, laboratories and other services; the absence of material
operational, regulatory, security, environmental or community disruption; and prevailing commodity prices, metallurgical
recoveries, costs and other economic assumptions.
Forward-looking information is subject to risks and uncertainties that may cause actual results to differ materially, including
that future drilling, modelling or technical studies may not confirm current interpretations, grades, widths, continuity,
potential resource additions or resource- category conversion; that geotechnical and comminution test work may not be
representative of the broader deposit; delays or changes in drilling, assay delivery, modelling, permitting or study schedules;
changes in metal prices, recoveries, costs or other assumpti ons; and access, title, regulator y, environmental, community,
social, security and political risks, together with the genera l risks of mineral exploration and development. 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 accepts responsibility for the adequacy or accuracy
of this news release.