Doré Copper Announces Significant Mineral Resource Increase for Corner Bay - Preliminary Economic Assessment Underway

TORONTO, Oct. 06, 2021 - Doré Copper Mining Corp. (the "Corporation" or "Dor? Copper") (TSXV: DCMC; OTCQX: DRCMF; FRA: DCM) is pleased to announce an updated and significantly expanded Mineral Resource Estimate ("MRE") for its flagship Corner Bay high-grade copper-gold project located approximately 55 kilometers by road from the Corporation's Copper Rand mill, near Chibougamau, Quebec.

This significant increase in the size of the MRE at Corner Bay represents an important step-change for the economic potential of an underground mining operation. This MRE will form the basis of the mine plan to be outlined in a preliminary economic assessment ("PEA") anticipated to be completed by January 2022.

Join us at our webinar on Wednesday, October 6 at 12:00 PM EST: https://us06web.zoom.us/s/84095898479?pwd=eGVPTytxUXl4a2ZwYlBQNi9IQzhFUT09

Highlights of the Corner Bay Updated MRE

• Corner Bay deposit contains an Indicated Resource of 2.66 Mt @ 2.68% Cu and 0.26 g/t Au and an Inferred Resource of 4.54 Mt @ 3.20% Cu and 0.27 g/t Au
• Contains 157 million pounds of copper in the Indicated category and 320 million pounds of copper in the Inferred category
• Corner Bay doubles in size from prior 2019 estimate:
  • An increase of 140% in total tonnage and 107% in contained copper metal in all resource categories
• Discovery cost of $0.02 per pound¹ since acquisition in 2017
• Excellent continuity of mineralization
• Infrastructure in place:
  • Ramp access to a vertical depth of 115 meters and two kilometers of development on three levels
  • Within trucking distance of the Corporation's 2,700 tpd mill
• Significant exploration potential exists to further increase the MRE:
  • Ongoing drilling program successfully connecting the Main Vein and Lower Deep Vein (both below dyke)
  • Deposit open down plunge below vertical depth of 1,100 meters
  • Subparallel zones untested
• PEA anticipated in January 2022

"When we acquired Corner Bay in 2017, we saw the opportunity to significantly grow the deposit and generate value. Our recent drilling success has increased the mineral resource tonnage by 360% since acquisition and 140% from the 2019 MRE, at a very low discovery cost of $0.02 per pound and with still significant exploration potential on the property. Corner Bay is now one of the few undeveloped high-grade copper deposits (+3% Cu) in the world today," said Ernest Mast, President and CEO of Dor? Copper.

"Our next priority is the completion of the PEA study for the re-development plan of a hub-and-spoke operation model with Corner Bay as the main feed to our centralized mill, supplemented by the Devlin and Joe Mann deposits. With the significant copper grade and size of this mineral resource, the existing mine, mill and tailings infrastructure, we anticipate demonstrating very attractive economics for our hub-and spoke operation. The plan is to continue exploration drilling from surface at Corner Bay and commence infill drilling in 2022 for a feasibility study anticipated in early 2023."

Dor? Copper has awarded BBA Inc. (Mont-Saint-Hilaire, Qu?bec) the contract to lead the PEA, which will include Corner Bay as the main feed to the Copper Rand mill along with Devlin and the former Joe Mann mine as secondary feed sources to its hub-and-spoke operation model.

The PEA will be using the MRE issued today for Corner Bay and the July 28, 2021 MRE for Joe Mann (Technical Report filed on September 10, 2021). Dor? Copper is currently finalizing a MRE update for the Devlin copper deposit, located 10 kilometers to the west of Corner Bay on the same property. A NI 43-101 technical report supporting the MREs for the Corner Bay and Devlin deposits will be filed on SEDAR (www.sedar.com) within 45 days.

Mineral Resource Estimate for Corner Bay

The MRE for the Corner Bay deposit (shown in Table 1 and Figure 1) was completed by SLR Consulting (Canada) Ltd. ("SLR"), an independent global mining advisory and consulting firm, using available drill hole data as of September 28, 2021. This MRE is based on a database containing a total of 324 diamond drill holes totaling 140,105 meters, of which 48 holes totaling 46,633 meters were completed by Dor? Copper from 2017 to 2021 (as of the cut-off date).

The Corner Bay deposit also has local significant silver and molybdenum concentrations which will be evaluated in the feasibility study. The deposit remains open down plunge and there are several parallel veins to the east and west that remain to be tested.

Table 1. Corner Bay Mineral Resource Estimate (Effective date of October 1, 2021)

Classification	Vein	Tonnage (Mt)	Cu Grade (%)	Au Grade (g/t)	Cu Contained (M lbs)	Au Contained (k oz)
Indicated	Main Vein 1	1.77	2.56	0.27	100	15
	Main Vein 2	0.50	2.87	0.27	32	4
	Main Below Dike	0.38	2.96	0.21	25	3
	Total	2.66	2.68	0.26	157	22
Inferred	Main Vein 1	0.35	2.77	0.32	22	4
	Main Vein 2	-	-	-	-	-
	Main Below Dike	3.39	3.09	0.25	231	27
	Lower Deep	0.42	5.43	0.44	51	6
	West Veins	0.26	1.68	0.16	9..6	1.4
	East Vein	0.11	2.91	0.21	7	1
	Total	4.54	3.20	0.27	320	39

Notes:

1. The stated Mineral Resources comply with the disclosure 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 are estimated at a cut-off grade of 1.3% Cu.
3. Mineral Resources are estimated using a long-term copper price of US$3.75 per pound, metallurgical copper recovery of 95%, and a US$/C$ exchange rate of 0.75.
4. A minimum mining width of two meters was used.
5. Bulk density for Main Vein 1 and Main Vein 2 above dyke is 3.1 g/cm³, East Vein is 2.90 g/cm³, Main Vein below dyke and Lower Deep Vein is 3.0 g/cm³, and West Veins WV and WV2 is 2.85 g/cm³ and WV3 is 2.92 g/cm³.
6. Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability.
7. Numbers may not add due to rounding.
   

Figure 1. Corner Bay Isometric View Showing the Mineral Resources and Potential for Expansion
https://www.globenewswire.com/NewsRoom/AttachmentNg/96967cc1-981f-405d-b2c0-df7372fb1160

Figure 2. Corner Bay Cross Section Showing the Mineralized Structures
https://www.globenewswire.com/NewsRoom/AttachmentNg/f8a8e712-7ec0-45e2-9f2f-fb489f3548e3

Mineral Resource Estimation Methodology

The Corner Bay MRE is based on eight veins, three of which are above the principal dyke, two are below and three are located on the west side of the deposit. For this estimation, the assays from the mineralized zones were uncapped for copper, capped at 6.0 g/t for gold and two meter composites were used, except for the Main Vein below dyke which used full length composites. The domains were estimated into sub-blocked models using a three-pass inverse distance squared (ID2) or cubed (ID3) interpolation approach. A minimum thickness of 2 meters was applied to all veins. Indicated Mineral Resources represent areas with drill hole spacing up to approximately 60 meters and Inferred Mineral Resources between 60 meters and 100 meters, with a copper cut-off grade of 1.3%.

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, and visual reviews in longitudinal section were performed.

Corner Bay Deposit

The Corner Bay deposit was discovered in 1982. The property was acquired by Ressources MSV Inc. in 1995 and subsequently merged with Campbell Resources Inc. ("Campbell"). Several exploration drilling programs were carried out up to 2008. An initial NI 43-101 MRE was prepared in 2006. In 2008, Campbell initiated an underground bulk sampling program by driving a ramp down to 115 meters below surface and establishing three levels (55, 75 and 105 meters). The bulk development sample totaling approximately 36,000 tonnes averaging 2.48% Cu and 0.44 g/t Au was processed at the Copper Rand mill with recoveries of 94.4% for copper and 81.5% for gold.

Dor? Copper, while operating as a private company, completed a drilling program of 14,047 meters in 14 holes (including wedges) in 2017-18 and reported a NI 43-101 MRE in 2019. Subsequent drilling programs by the Corporation in 2020 and 2021 have successfully expanded the deposit along strike and down plunge.

The Corner Bay property is located on the southern flank of the Lac Dore Complex. An anorthositic sequence hosts the copper mineralized shear, striking approximately north-south and dipping 70? west, which extends from surface down to 1,300 meters vertically (open) and over one kilometer along strike. The deposit is bisected by the regional Gabbro Isle dyke, a large north-south striking diorite dyke dipping sub-vertically.

The deposit consists of four main mineralized veins (subparallel Main Vein 1 and Main Vein 2 above the dyke, Main Vein below the dyke, and Lower Deep Vein) that make up the bulk of the deposit, and four other parallel smaller veins (West Veins and East Vein) (Figures 1 and 2). The Main Vein below the dyke is the continuation of the mineralization above in Main Vein 1 and 2, but as the name implies, it is located below the Gabbro Isle dyke and dips 80? towards the west. The Lower Deep Vein is a deeper lens in the same shear, with the same general orientation as the other veins, dipping 65? west. The current drilling program is successfully demonstrating continuity between the Main Vein below the dyke and the Lower Deep Vein (assays are pending). This part of the deposit has limited strike extension and remains open down plunge. Identified and drilled in 2020 and 2021, the West Veins are three parallel veins located 60 meters to 100 meters below surface and located approximately 400 meters west of the Main Vein 1 and 2. They are sub-vertical and range in thickness from 0.5 meter to 3.0 meters. The mineralized structure hosting these veins extends for hundreds of meters along strike and still remains sparsely drilled. A new parallel vein (East Vein) was identified 200 meters to the east of the Main Vein above the dyke. Both the West and East Veins are open along strike and at depth.

In general, the mineralization ranges in thickness from 0.4 meter to over 20 meters (all eight veins have been modelled with a two meter minimum true thickness). Mineralization consists mostly of pyrite and chalcopyrite with sporadic pyrrhotite.

Qualified Persons

The MRE for Corner Bay was prepared by Luke Evans, M.Sc., P.Eng., ing. and Marie-Christine Gosselin, B.Sc., P.Geo, of SLR, both "Independent Qualified Persons" as defined by NI 43-101. 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 MREs.

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.

Town Hall Webinar

Ernest Mast, President and CEO of Dor? Copper will discuss the MRE update for Corner Bay, the Corporation's key asset for an eventual hub-and-spoke operation, at a webinar on Wednesday, October 6 at 12:00 PM EST.

To participate in the Town Hall Webinar, please register here with your full name: https://us06web.zoom.us/s/84095898479?pwd=eGVPTytxUXl4a2ZwYlBQNi9IQzhFUT09

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 gold². 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 January 2022. The Corporation is completing its 2021 drilling program of 50,000 meters on its properties in the Lac Dor? and Chibougamau area of Qu?bec.

For further information, please contact:

Ernest Mast	Laurie Gaborit
President and Chief Executive Officer	Vice President, Investor Relations
Phone: (416) 792-2229	Phone: (416) 219-2049
Email: emast@Dor?copper.com	Email: lgaborit@Dor?copper.com

For more information, please visit: www.dorecopper.com
Facebook: Dor? Copper Mining
LinkedIn: Dor? Copper Mining Corp.
Twitter: @DoreCopper
Instagram: @DoreCopperMining

1. Non-audited estimation using exploration expenditures from October 2017 up to June 30, 2021 divided by the increase in the total pounds of copper in mineral resources. Exploration expenditures include drillings costs, assays costs, geophysics, geochemistry, and a portion of indirect costs such as consultants, maintenance, travel and operations support. This is considered a non-IFRS financial measure.

2. 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 significant increase in the size of the MRE at Corner Bay representing an important step-change for the economic potential of an underground mining operation, PEA to be completed by January 2022, significant exploration potential to further increase the MRE, demonstrating very attractive economics for our hub-and spoke operation, plan to continue exploration drilling from surface at Corner Bay and commence infill drilling in 2022, feasibility study anticipated in early 2023, 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.