Doré Copper Announces Its Initial Mineral Resource at Joe Mann

Commenting on the result, Ernest Mast, President and CEO of Dor? Copper, stated: "This is a good start towards our exploration and re-development plan for the former Joe Mann mine as part of our hub-and-spoke operation model, which will include several mines feeding our centralized mill having a capacity of 2,700 tpd. Our plan is to continue future drilling activities from underground where there is excellent potential for the gold mineralization to continue down plunge at both the West and Main Zones. We are also confident that with additional drilling the average gold grade of the deposit will increase."

Mineral Resource Estimate

The MRE for the Joe Mann deposit was completed by SLR Consulting Ltd. ("SLR") and contains an Inferred Mineral Resource of 608,000 tonnes at an average grade of 6.78 g/t Au for 133,000 contained ounces of gold (see Table below).

Joe Mann Mineral Resource Estimate (Effective date of July 21, 2021)

Notes:

1. The stated Mineral Resources comply with the requirements of National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101") and are classified in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum's "CIM Definition Standards - For Mineral Resources and Mineral Reserves" (the "CIM Definition Standards").
2. Mineral Resources were estimated at a cut-off grade of 2.60 g/t Au, based on operating cost projections and applicable metallurgical recovery (83%). The cut-off grade was used in combination with a minimum mining width factor of 1.2 meters to define the resource. A small number of lower grade blocks within Main 01 have been included for continuity.
3. Mineral Resources were estimated using a long-term gold price of US$1,800/oz and a US$/C$ exchange rate of 0.75.
4. Bulk density of 2.84 t/m³.
5. Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability.
6. Numbers may not add/multiply due to rounding.

The Qualified Persons are not aware of any environmental, permitting, legal, title, taxation, socio-economic, marketing, political, or other relevant factors that could materially affect the MRE.

This initial MRE incorporates a total of 52 diamond drill holes totaling 17,622 meters, including 48 historic holes totaling 12,311 meters and four holes completed by Dor? Copper in late 2020 totaling 5,312 meters (see news release January 25, 2021).

Mineral Resource Estimation Methodology

The MRE is based on two veins in the West Zone and one vein in the Main Zone of the former Joe Mann mine, directly below existing mine infrastructure that last operated in 2007 (vertical depth of 870 meters for the West Zone and 1,050 meters for the Main Zone from surface), within which capped, full length composites have been estimated into sub-blocked models using a two-pass inverse distance cubed (ID3) interpolation approach. Vein orientations were confirmed through observed vein angles in drill core with consideration to overlying mined out stope orientations. A minimum thickness of 1.2 meters was applied to all veins. Grades were capped at 45 g/t Au. Inferred Mineral Resources represent areas with drill hole spacing up to 100 meters and above a cut-off grade of 2.6 g/t Au. Within Main 01, a small amount of lower grade material was included to preserve continuity.

The Mineral Resource domain dimensions approximate 200 x 400 meters for West 01, 250 x 175 meters for West 02, and 170 x 300 meters for Main 01. The West Zone is approximately 1,100 meters west of the Main Zone. All three veins remain open down plunge and along strike to the east.

Mineral Resource domains and block modelling work was performed using Leapfrog Geo and Edge software. In addition to standard historical data and database validation techniques, wireframe and block model validation procedures including wireframe to block volume confirmation, statistical comparisons with composite and nearest neighbour estimates, visual reviews in longitudinal section were also completed.

NI 43-101 Technical Report

A NI 43-101 technical report disclosing the MRE for the Joe Mann deposit will be filed on SEDAR (www.sedar.com) within 45 days.

Joe Mann Deposit

The Joe Mann mine produced a total of 1,173,238 ounces of gold, 28.7 million pounds of copper, and about 607,000 ounces of silver from 1956 to 2007 (4.75 Mt grading 8.26 g/t Au, plus 0.25% Cu and 5 g/t Ag)¹. From 2004 until its closure in 2007, the ore was processed at the Company's Copper Rand mill located 60 kilometers to the north.

Following the closure of the mine, two of three diamond drill holes completed in 2008 from the 945 meters level intersected the Main Zone. The first hole (EE-189B) intersected the Main Zone at 170 meters underneath the lowest level (1,050 meters) with 26.66 g/t Au and 0.40% Cu over 1.88 meters and 14.72 g/t Au over 1.2 meters. The second hole (EE-188) also intersected the Main Zone with 30.3 g/t Au and 1.3% Cu over 3.02 meters and the South Zone with 9.23 g/t Au over 0.91 meter. With no funds to further continue this exploration program, Gold Bullion dropped the option and the mine was allowed to flood during the spring of 2008.

Dor? Copper optioned the property in January 2020 and in late 2020 completed 8,343 meters of drilling to test the depth extension of the Main and West Zones, and other structures on the Joe Mann property. Two holes tested the Main Zone below the underground workings to test the continuity of the high-grade gold mineralization identified by two prior holes (refer to above). Hole JM-20-02A intersected the Main Zone, approximately 120 meters up-dip from these two historical intercepts, and returned 6.32 g/t Au and 0.52% Cu over 1.3 meters, including 17.7 g/t Au and 1.23% Cu over 0.45 meter; and 2.29 g/t Au over 5.95 meters, including 5.64 g/t Au over 1.7 meters. Four holes tested the downdip extension of the West Zone, which was mined from 2004 to 2007 up to a depth of 890 meters. All four holes intersected the West Zone at depths of 270 to 400 meters below the mined area. The best hole (JM-20-06W3) intersected 10.34 g/t Au and 0.27% Cu over 4.0 meters and at a further 11 meters downhole intersected 13.70 g/t Au and 0.42% Cu over 0.5 meter. These two intercepts are located 100 meters down plunge from historical high-grade intercepts of 5.0 meters of 10.3 g/t Au (hole EW78_D), 3.2 meters of 16.1 g/t Au (hole EW79_D), and 3.3 meters of 10.4 g/t Au (hole EW57_D). Refer to news release dated January 25, 2021.

Joe Mann is characterized by east-west striking shear hosted veins that extend beyond 1,000 meters vertically with mineralization identified over a 3-kilometer strike length. These shear zones form part of the Opawica-Guercheville deformation zone, a major deformation corridor cutting the mafic volcanic rocks of the Obatogamau Formation in the north part of the Caopatina Segment. The gabbro sill hosts the Main Zone and the West Zone at the mine, while the South Zone is found in the rhyolite.

In the mine area, gold mineralization is hosted in quartz-carbonate veins that vary in thickness from five centimeters to 1.5 meters, averaging 0.75 meters. The veins are intensely brecciated and often boudinaged and folded. Gold is closely linked pyrite, pyrrhotite, and chalcopyrite.

Qualified Persons

The MRE for Joe Mann was prepared by Marie-Christine Gosselin and Valerie Wilson of SLR, both "Independent Qualified Persons" as defined by NI 43-101.

Andrey Rinta, P.Geo., the Exploration Manager of the Corporation and a "Qualified Person" within the meaning of National Instrument 43-101, has reviewed and approved the technical information contained in this news release.

About Dor? Copper Mining Corp.

Dor? Copper Mining Corp. is a copper-gold explorer and developer in the Chibougamau area of Qu?bec, Canada. The Corporation is focussed on implementing its hub-and-spoke development strategy by advancing its key high-grade copper-gold brownfield projects towards a restart of operations. Our goal is to achieve an annual production of 60 M lbs of copper equivalent (or 100,000 oz gold equivalent).

The Corporation has consolidated a large land package in the prolific Lac Dor?/Chibougamau and Joe Mann mining camps that has produced 1.6 billion pounds of copper and 4.4 million ounces of gold¹. The land package includes 13 former producing mines, deposits and resource target areas within a 60-kilometre radius of the Company's 2,700 tpd mill (Copper Rand Mill).

Dor? Copper plans to deliver a PEA of its hub-and-spoke model in late 2021. Currently, the Corporation is completing a 30,000-metre drilling program at its Corner Bay (Cu-Au) project, of which approximately 19,000 meters will be included in an updated mineral resource estimate expected in Q3 2021.

For further information, please visit the Corporation's website at www.Dor?copper.com or refer to Dor? Copper's SEDAR filings at www.sedar.com or contact:

1. Sources for historic production figures: Economic Geology, v. 107, pp. 963-989 - Structural and Stratigraphic Controls on Magmatic, Volcanogenic, and Shear Zone-Hosted Mineralization in the Chapais-Chibougamau Mining Camp, Northeastern Abitibi, Canada by Fran?ois Leclerc et al. (Lac Dor?/Chibougamau mining camp) and NI 43-101 Technical Report on the Joe Mann Property dated January 11, 2016 by Geologica Groupe-Conseil Inc. for Jessie Ressources Inc. (Joe Mann mine).

Information Concerning Estimates of Mineral Reserves and Resources
The Mineral Reserve and Mineral Resource estimates in this press release have been disclosed in accordance with NI 43-101, which differs significantly from the requirements of the U.S. Securities and Exchange Commission (the "SEC"), and information with respect to mineralization and Mineral Reserves and Mineral Resources contained herein may not be comparable to similar information disclosed by U.S. companies. The requirements of NI 43-101 for identification of ''reserves'' are not the same as those of the SEC, and reserves reported by the Company in compliance with NI 43-101 may not qualify as ''reserves'' under SEC standards. Under U.S. standards, mineralization may not be classified as a ''reserve'' unless the determination has been made that the mineralization could be economically and legally produced or extracted at the time the reserve determination is made. In addition, and without limiting the generality of the foregoing, this press release uses the terms ''Measured Resources'', ''Indicated Resources'' and ''Inferred Resources''. U.S. investors are advised that, while such terms are recognized and required by Canadian securities laws, the SEC has not recognized them in the past. U.S. investors are cautioned not to assume that any part of a ''Measured Resource'' or ''Indicated Resource'' will ever be converted into a ''reserve''. U.S. investors should also understand that ''Inferred Resources'' have a great amount of uncertainty as to their existence and as to their economic and legal feasibility. It cannot be assumed that all or any part of ''Inferred Resources'' exist, are economically or legally mineable or will ever be upgraded to a higher category. Under Canadian securities laws, ''Inferred Resources'' may not form the basis of feasibility or pre-feasibility studies except in certain cases. Disclosure of ''contained ounces'' in a Mineral Resource is a permitted disclosure under Canadian securities laws, however, the SEC normally only permits issuers to report mineralization that does not constitute ''reserves'' by SEC standards as in place tonnage and grade, without reference to unit measures. Accordingly, information concerning mineral deposits set forth in this press release may not be comparable with information made public by companies that report in accordance with U.S. standards.

The SEC has adopted amendments to its disclosure rules to modernize the mineral property disclosure requirements under the U.S. Securities Exchange Act of 1934, as amended (the "Exchange Act"). These amendments became effective February 25, 2019 (the "SEC Modernization Rules") with compliance required for the first fiscal year beginning on or after January 1, 2021. Under the SEC Modernization Rules, the historical property disclosure requirements for mining registrants included in Industry Guide 7 under the U.S. Securities Act of 1933, as amended, will be rescinded and replaced with disclosure requirements in subpart 1300 of SEC Regulation S-K. As a result of the adoption of the SEC Modernization Rules, the SEC now recognizes estimates of "Measured Mineral Resources", "Indicated Mineral Resources" and "Inferred Mineral Resources." In addition, the SEC has amended its definitions of "Proven Mineral Reserves" and "Probable Mineral Reserves" to be "substantially similar" to the corresponding standards under NI 43-101. While the SEC will now recognize "Measured Mineral Resources", "Indicated Mineral Resources" and "Inferred Mineral Resources", U.S. investors should not assume that any part or all of the mineralization in these categories will ever be converted into a higher category of Mineral Resources or into Mineral Reserves. Mineralization described using these terms has a greater amount of uncertainty as to its existence and feasibility than mineralization that has been characterized as reserves. Accordingly, U.S. investors are cautioned not to assume that any Measured Mineral Resources, Indicated Mineral Resources, or Inferred Mineral Resources that the Company reports are or will be economically or legally mineable. Further, "Inferred Mineral Resources" have a greater amount of uncertainty as to their existence and as to whether they can be mined legally or economically. Therefore, U.S. investors are also cautioned not to assume that all or any part of the "Inferred Mineral Resources" exist. There is no assurance that any Mineral Reserves or Mineral Resources that the Company may report as "Proven Mineral Reserves", "Probable Mineral Reserves", "Measured Mineral Resources", "Indicated Mineral Resources" and "Inferred Mineral Resources" under NI 43-101 would be the same had the Company prepared the reserve or resource estimates under the standards adopted under the SEC Modernization Rules.

Mineral Resources are not Mineral Reserves, and do not have demonstrated economic viability, but do have reasonable prospects for economic extraction. Measured and Indicated Mineral Resources are sufficiently well defined to allow geological and grade continuity to be reasonably assumed and permit the application of technical and economic parameters in assessing the economic viability of the Mineral Resource. Inferred Mineral Resources are estimated on limited information not sufficient to verify geological and grade continuity or to allow technical and economic parameters to be applied. Inferred Mineral Resources are too speculative geologically to have economic considerations applied to them to enable them to be categorized as Mineral Reserves. There is no certainty that Mineral Resources of any classification can be upgraded to Mineral Reserves through continued exploration.

Cautionary Note Regarding Forward-Looking Statements
This news release includes certain "forward-looking statements" under applicable Canadian securities legislation. Forward-looking statements include predictions, projections and forecasts and are often, but not always, identified by the use of words such as "seek", "anticipate", "believe", "plan", "estimate", "forecast", "expect", "potential", "project", "target", "schedule", "budget" and "intend" and statements that an event or result "may", "will", "should", "could" or "might" occur or be achieved and other similar expressions and includes the negatives thereof. Specific forward-looking statements in this press release include, but are not limited to, the Corporation's plans to integrate the former Joe Mann mine into its hub-and-spoke operation model, anticipating the completion of a preliminary economic assessment ("PEA") at the end of 2021 with Corner Bay as the main feed to the Copper Rand mill, continuing future drilling activities at Joe Mann from underground, the excellent potential for the high-grade gold mineralization at Joe Mann to continue down plunge at both the West and Main Zones, the confidence that with additional drilling the average gold grade of the deposit will increase, implementing a hub-and-spoke development strategy by advancing the Corporation's key high-grade copper-gold brownfield projects towards a restart of operations, and the Corporation's goal of achieving an annual production of 60 M lbs of copper equivalent (or 100,000 oz gold equivalent).

All statements other than statements of historical fact included in this release, including, without limitation, statements regarding the timing and ability of the Corporation to receive necessary regulatory approvals, and the plans, operations and prospects of the Corporation and its properties are forward-looking statements. Forward-looking statements are necessarily based upon a number of estimates and assumptions that, while considered reasonable, are subject to known and unknown risks, uncertainties and other factors which may cause actual results and future events to differ materially from those expressed or implied by such forward-looking statements. Such factors include, but are not limited to, actual exploration results, changes in project parameters as plans continue to be refined, future metal prices, availability of capital and financing on acceptable terms, general economic, market or business conditions, uninsured risks, regulatory changes, delays or inability to receive required regulatory approvals, health emergencies, pandemics and other exploration or other risks detailed herein and from time to time in the filings made by the Corporation with securities regulators. Although the Corporation has attempted to identify important factors that could cause actual actions, events or results to differ from those described in forward-looking statements, there may be other factors that cause such actions, events or results to differ materially from those anticipated. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements. The Corporation disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

Neither 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.