Sirios Announces Significant Increase in Cheechoo Open-Pit Gold Resources and Introduces Underground Resources
TSX-V: SOI July 10, 2025
Sirios Announces Significant Increase in Cheechoo Open-Pit
Gold Resources and Introduces Underground Resources
Montréal, Québec – Sirios Resources Inc. (TSX-V: SOI; OTCQB: SIREF) (“Sirios”) is pleased to report
an updated Mineral Resource Estimate (“ MRE”) for its 100% -owned Cheechoo Gold Project (the
“Project”), located in Eeyou Istchee James Bay , Québec, less than 15 km from Dhilmar Ltd. ’s
Éléonore gold mine.
Highlights of the 2025 MRE include:
• 1.3 million ounces at 1.12 g/t Au (Indicated Resources);
• 1.7 million ounces at 1.23 g/t Au (Inferred Resources);
o including 446,000 ounces in underground resources at 3.09 g/t Au
• Significant gold grade increase over the 2022 MRE:
o 19% increase of the open-pit indicated grade (from 0.94 g/t Au to 1.12 g/t Au);
o 38% increase of the open-pit inferred grade (from 0.73 g/t Au to 1.01 g/t Au);
• Low strip ratio of 2.9:1;
• Conceptual Exploration Target of 31 to 40 million tonnes of mineralization grading
between 1.27 to 1.45 g/t Au.
Dominique Doucet, President and CEO of Sirios Resources, commented: “The substantial increase
in gold resources at Cheechoo reflects the dedicated efforts of our team since the last mineral
resource estimate. The total resources now position the project as a highly compelling opportunity
for mining development —just a few k ilometers from a producing gold mine. Furthermore, we are
especially enthusiastic about the growth potential represented by our consultants’ conceptual
Exploration Target, which includes targets for underground resources —an exciting prospect given
that drilling to date has largely focused on near-surface zones. With this new MRE in hand, Sirios is
now outlining a strategy to fast-track additional resource growth and advance the project toward the
development stage. ”
Webinar
Sirios will host a webinar today to present the updated MRE and outline the next steps in advancing
the Project. A Q&A session will follow the presentation.
• French: July 10, 1:00 p.m. (EDT)
• English: July 10, 2:00 p.m. (EDT)
Cheechoo Project Mineral Resource Estimate
The updated Mineral Resource Estimate is based on 345 drill holes, totalling 82,717 meters, including
8,660 meters since 2022. This MRE introduces a new underground component and is based on a new
geological model that has revealed previously underestimated, higher -grade zones within the
deposit. An interactive 3D viewer of the new model is now available at sirios.com/en/cheechoo.
Table 1: Indicated and Inferred Mineral Resources Estimate (MRE)
Pit
constrained
0.3 g/t Au Cut-off grade Tonnes (t) Au (g/t) Au (koz)
Indicated 34,993,000 1.12 1,262
Inferred 38,222,000 1.01 1,242
Stope
constrained
1.5 g/t Au Cut-off grade Tonnes (t) Au (g/t) Au (koz)
Inferred 4,493,000 3.09 446
TOTAL
0.3 & 1.5 g/t Au Cut-off grade Tonnes (t) Au (g/t) Au (koz)
Total Indicated 34,993,000 1.12 1,262
Total Inferred 42,715,000 1.23 1,688
1. The independent qualified person for the MRE, as defined by National Instrument (“NI”) 43 -101
guidelines, is Pierre Luc Richard, P .Geo., of PLR Resources Inc. with contributions from Alexandre
Burelle, P .Eng., of Evomine for cut -off values, open pit optimi zation solids and underground
optimization solids, and Christian Laroche, P .Eng., from Synectiq, for metallurgical parameters. The
effective date of the MRE is July 01, 2025.
2. These Mineral Resources are not mineral reserves as they have no demonstrated economic viability.
No economic evaluation of these Mineral Resource has been produced. The quantity and grade of
reported Inferred Resources in this MRE are uncertain in nature and there has been insufficient drilling
to define these Inferred Resources as Indicated. However, it is reasonably expected that the majority
of Inferred Mineral Resources could be upgraded to Indicated category with continued drilling.
3. The Qualified Persons are not aware of any known environmental, permitting, legal, title -related,
taxation, socio -political, marketing or other relevant issues that could materially affect the Mineral
Resource Estimate.
4. Calculations used metric units (metres (m), tonnes (t), and g/t). Metal contents in the above table are
presented in troy ounces (metric tonne x grade / 31.103475). Values were rounded, and any
discrepancies in total amounts are due to rounding errors.
5. The Cheechoo Mineral Resource estimate follows the November 29, 2019, CIM Estimation of Mineral
Resources and Mineral Reserves Best Practice Guidelines.
Figure 1: 2025 MRE Pit Shell and Block Model
Conceptual Exploration Target
A significant Exploration Target—with both open -pit and underground potential —was identified by
our consultant PLR Resources during the preparation of the MRE.
Highlights of the Exploration Target:
• Estimated total of 31 to 40 million tonnes of mineralization grading between 1.27 to 1.45 g/t
Au, including:
o Open-pit component:
25 to 32 million tonnes of mineralization grading between 0.90 to 1.05 g/t Au;
o Underground component:
6 to 8 million tonnes of mineralization grading between 2.80 to 3.05 g/t Au.
This conceptual Exploration Target is integrated into the litho-structural model used for the MRE, with
the aim of facilitating future targeting and drill hole planning. PLR Resources proposed a 20,000 m
drill hole program to provide infill drilling aiming at converting part of the Exploration Target into
Inferred Resources, test structural features and potentially increase the size of the Exploration Target.
Disclosure warnings in respect to an exploration target review
• An Exploration Target is not a National Instrument 43-101 compliant resource or reserve.
• The Exploration Target is confirmed only as a target for further exploration.
• Potential quantity and grades are conceptual in nature only.
• There has not been sufficient drilling to define any mineral resource on this Exploration Target; drilling
intercepts crosscut the Exploration Target but drill spacing is too scarce to classify these blocks as
Inferred Mineral Resources.
• There is no certainty that further drilling will result in the target being delineated as a mineral resource.
• The assessment of the target for further exploration was completed by PLR Resources, a consultant
independent of the company. The estimation of the potential quantity and grade of the exploration
target was based on the same drill hole database used for th e Mineral Resource Estimate. With the
available drilling information, PLR developed conceptual gold mineralization volumes, constrained by
interpreted lithological and structural models. The original core samples were composited, and the
composited gold assays were capped (similarly to the Mineral Resource Estimate) after evaluating the
statistical distributions on probability plots. The gold values were interpolated into a three-dimensional
block model using Ordinary Kriging. To estimate a tonnage, PLR use d the same specific gravity values
used for the Mineral Resource Estimate.
• An open-pit scenario limited by the Project’s boundary as well as DSO stopes were run to constrain the
Exploration Target.
Parameters and criteria used for the Mineral Resource Estimate (MRE)
Table 2: General pit and stope parameters used for the Mineral Resource Estimate
PARAMETER UNIT OPEN PIT UNDERGROUND
Revenue
Gold price USD/oz 2,500 2,500
Exchange rate CAD/USD 1.35 1.35
Operating costs
Mining cost CAD/t mined 4 75
Incremental bench cost CAD/t mined/10m bench 0.05 N/A
Processing cost CAD/t milled 17.5 17.5
General and administration cost CAD/t milled 5.5 5.5
Mineralized material based costs CAD/t milled 23 98
Mining
Selective mining unit m 5 x 5 x 5 N/A
Minimum mining width m N/A 2.5
Stope height m N/A 25
Minimum slope angle – overburden deg 25 N/A
Minimum slope angle – rock deg 50 N/A
Cut-off grade
Cut-off grade applied g/t milled 0.25 1.5
• Resources are presented as undiluted and in situ for the open-pit scenario and include internal dilution
for the underground scenario and are considered to have reasonable prospects for economic
extraction. The constraining pit shell was developed using overall pit slopes of 50 degrees in bedrock
and 25 degrees in overburden. The pit optimization to develop the mineral resource -constraining pit
shells was done using the pseudoflow algorithm in Deswik software. The stope optimization to develop
the underground mineral resource was done using Deswik.SO software.
• The MRE wireframe was prepared using Leapfrog Edge v.2024.1.3 and is based on 345 drill holes,
totalling 82,717 meters drilled and 56,337 assays. The cut-off date for the drill hole database was May
13, 2025.
• Composites of 1.5 metres were created inside the mineralization domains. High -grade capping was
done on the composited assay data. Based on individual statistical study for each zone, composites
were capped at 25.0 g/t Au for the HG zones, 2.0 g/t Au for t he corridors and 1.0 g/t for the tonalite
intrusion. A three-pass capping strategy defined by capping values decreasing as interpolation search
distances increase was used in the grade estimation for the HG zones.
• Pit constrained Mineral Resources for the base case are reported at a cut-off grade of 0.3 g/t Au; DSO-
constrained Mineral Resources for the base case are reported at a cut -off grade of 1.5 g/t Au and
include internal dilution (must-take). The cut-off grades will be re-evaluated in light of future prevailing
market conditions and costs.
• Specific gravity values were estimated using data available in the drill hole database. Density values
between 2.64 and 2.76 were applied to the host rocks.
• Grade model resource estimation was calculated from drill hole data using an Ordinary Kriging
interpolation method in a sub-blocked model using blocks measuring 5 m x 5 m x 5 m in size and sub-
blocks down to 0.625m x 0.625m x 0.625m. Both ordinary kriging (OK) and inverse square distance
(ID2) interpolation methods were tested, resulting in no material difference in the Mineral Resource
Estimates.
• The Indicated and Inferred Mineral Resource categories are constrained to areas where drill spacing
is less than 50m and 100 metres respectively and show reasonable geological and grade continuity.
Cautionary Statement Regarding Mineral Resources
The mineral resources disclosed in this press release conform to NI43-101 standards and guidelines and were
prepared by independent qualified persons. The above-mentioned mineral resources are not mineral reserves
as they do not have demonstrated economic viability. The quantity and grade of the reported Inferred Mineral
Resources are conceptual in nature and are estimated based on limited geological evidence and sampling.
Geological evidence is sufficient to imply but not verify geological grade and/or quality of continuity. An Inferred
Mineral Resource has a lower level of confidence relative to a Measured or Indicated Mineral Resource and
constitutes an insufficient level of confidence to allow conversion to a Mineral Reserve. It is reasonably
expected, but not guaranteed, that the majority of Inferred Mineral Resources could be upgraded to Measured
or Indicated Mineral Resources with additional drilling. The National Instrument 43 -101 Technical Report,
including the mineral resources for the Cheechoo Project contained in this news release, will be delivered and
filed on SEDAR by Sirios Resources Inc. within 45 days of the date of this news release.
Qualified persons
The Mineral Resource Estimate and other scientific and technical information in this news release
has been prepared and approved by independent qualified persons for purposes of NI 43-101: Pierre
Luc Richard, P .Geo., of PLR Resources Inc. with contributions from Alexandre Burelle, P .Eng., of
Evomine for cut-off values, open pit optimization solids and underground optimization solids, and
Christian Laroche, P .Eng., from Synectiq, for metallurgical parameters.
About the Cheechoo Gold Project
The Cheechoo Gold Project is a flagship asset of Sirios Resources Inc., located in the Eeyou Istchee
James Bay territory of Québec, less than 15 km from the Éléonore gold mine. The project is 100%
owned by Sirios and is recognized for its significant expansion and development potential, targeting
both large -scale open -pit and higher -grade underground mining scenarios. Learn more at
sirios.com/en/cheechoo.
About the Éléonore Gold Mine
The Éléonore Mine is an underground gold operation located in the Eeyou Istchee James Bay region
of Québec, directly adjacent to Sirios' Cheechoo Property. Commercial production at Éléonore
began in April 2015. In 2024, Dhilmar Ltd. acquired the mine from Newmont Corporation in a $795
million USD transaction and is now the current operator.
About PLR Resources
PLR Resources specializes in mineral resource estimates and project evaluations and offers a wide
variety of services, from grassroots exploration planning to feasibility studies and mining operation
optimization, serving clients that include juniors, major operators as well as financial experts seeking
reliable and realistic advice.
For more information, please contact:
Dominique Doucet, P .Eng., CEO
450-482-0603
www.sirios.com
Cautionary note regarding forward-looking statements
This news release contains “forward -looking information” within the meaning of applicable
Canadian securities legislation based on expectations. estimates and projections as at the date of
this news release. Forward -looking information involves risks, unce rtainties and other factors that
could cause actual events, results. Performance, prospects and opportunities to differ materially
from those expressed or implied by such forward -looking information. Factors that could cause
actual results to differ materially from such forward-looking information include, but are not limited
to, capital and operating costs varying significantly from estimates; the preliminary nature of
metallurgical test results; delays in obtaining or failures to obtain required governmen tal,
environmental or other project approvals; uncertainties relating to the availability and costs of
financing needed in the future; changes in equity markets; inflation; fluctuations in commodity
prices; delays in the development of projects; the other risks involved in the mineral exploration and
development industry; and those risks set out in the Company’s public documents filed on SEDAR at
www.sedar.com. Although the Company believes that the assumptions and factors used in preparing
the forward-looking information in this news release are reasonable, undue reliance should not be
placed on such information, which only applies as of the date of this news release, and no assurance
can be given that such events will occur in the disclosed time frames or at all. The Company
disclaims any intention or obligation to update or revise any forward-looking information, whether as
a result of new information, future events or otherwise, other than as required by law.
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 release.
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