Doré Copper Intersects 6.8 Meters at 3.67% Copper and 0.26 g/t Gold at Corner Bay - Continues to Expand Deposit

With the successful 2021 drilling program to date, Doré Copper is increasing the Corner Bay drilling program from 16,500 meters to 30,000 meters. The Corporation has established the assay cut-off date at around mid-July to include hole CB-21-32W2 for an updated mineral resource estimate in early Q3. The preliminary economic assessment ("PEA") to support an eventual hub-and-spoke restart of the camp using its existing 2,700 tpd mill, with Corner Bay as the main feed to the mill, is anticipated at the end of 2021.

Drilling Highlights

Main Vein below dyke

• CB-21-30: 10.45 meters of 2.23% Cu, 0.52 g/t Au and 7.7 g/t Ag, including 4.6 meters of 4.04% Cu, 1.02 g/t Au and 13.7 g/t Ag
  
  
• CB-21-32W1: 6.8 meters of 3.67% Cu, 0.26 g/t Au and 9.7 g/t Ag - 65 METRES UP-DIP FROM 5.5 meters of 3.46% Cu, 0.25 g/t Au and 8.4 g/t Ag (Hole CB-21-32)
  
  
• CB-21-34: 3.6 meters of 4.52% Cu, 0.12 g/t Au and 8.1 g/t Ag, including 1.65 meters of 9.75% Cu, 0.24 g/t Au and 14.7 g/t Ag
  

Main Vein above the dyke

• CB-21-31: 3.0 meters of 4.09% Cu, 0.37 g/t Au and 10.9 g/t Ag
  
  
• CB-21-35: 7.3 meters of 1.43% Cu, 0.17 g/t Au and 4.9 g/t Ag, including 3.1 meters of 2.03% Cu, 0.32 g/t Au and 6.6 g/t Ag
  
  
• CB-21-37: 4.55 meters of 3.02% Cu, 0.42 g/t Au, and 12.9 g/t Ag
  

"The 2021 drilling program continues to expand the size of the high-grade copper-gold Corner Bay deposit. These positive results from two different areas of the deposit will be included in the upcoming mineral resource estimate. Our confidence continues to grow in reaching our key target of 5 million tonnes of resources, which would be an increase of approximately 65% from our 2019 NI 43-101 mineral resource estimate. We are also encouraged to see good continuity and increased thicknesses at depth which lend itself to increased mining rates over time," stated Ernest Mast, President and CEO of Dor? Copper. "The furthest southern intercepts (hole CB-21-32 and 32W1) are indicating that the growth potential towards the south is open along strike and up-dip. We are now increasing our drilling program to 30,000 meters to continue delineating the mineralization along strike to the south."

Corner Bay Drilling Program

Results to date from the 2021 drilling program have successfully continued to expand the copper-gold mineralization at Corner Bay, bringing the total strike of the mineralization to over 900 metres. The intercepts of holes CB-21-30 (10.45 meters of 2.23% Cu, 0.52 g/t Au and 7.7 g/t Ag, including 4.6 meters of 4.04% Cu, 1.02 g/t Au and 13.7 g/t Ag), CB-21-32W1 (14.2 meters of 2.26% Cu, 0.18 g/t Au and 7.4 g/t Ag, including 6.8 meters of 3.67% Cu, 0.26 g/t Au and 9.7 g/t Ag), and CB-21-34 (3.6 meters of 4.52% Cu, 0.12 g/t Au and 8.1 g/t Ag, including 1.65 meters of 9.75% Cu, 0.24 g/t Au and 14.7 g/t Ag) have expanded the Main Vein (below the diorite dyke) along strike to the south by approximately 200 meters from the 2020 drilling program (see Figure 1 and Table 1). The high-grade copper intercept of 6.8 meters of 3.67% Cu in CB-21-32W1 (southernmost hole for this part of the deposit) is located 65 meters up-dip from hole CB-21-32, which intersected 5.5 meters of 3.46% Cu. Holes CB-21-32 and CB-21-32W1 are located 380 meters south along strike from the 2019 mineral resource limit. The intercept in hole CB-21-32W1 further demonstrates that the "La Chib" fault, which limited the upper part of the deposit along strike to the south, does not limit the mineralization in the deeper part of the deposit and therefore opens up this part of the deposit along strike.

With these positive results and the recent financing, Dor? Copper is increasing the 2021 drilling program at Corner Bay to 30,000 meters to test the mineralization further along strike to the south and up-dip and look at connecting the Deep Vein Main lens to the Main Vein below the dyke (step out holes from hole CB-21-34 to the north).

In the Main Vein above the dyke, assays received from six holes are expected to increase the size of the resource and improve the drill density in this area. Significant intercepts include: 4.55 meters of 3.02% Cu, 0.42 g/t Au, and 12.9 g/t Ag (CB-21-37) and 3.0 meters of 4.09% Cu, 0.37 g/t Au and 10.9 g/t Ag (CB-21-31) (see Figure 2 and Table 1).

Additional drill holes in proximity to the Main Vein have intersected significant copper mineralization and will be included in the upcoming mineral resource estimate. This includes three new parallel veins near surface (West Vein area) located 400 meters to the west of the Main Vein (refer to news release dated May 17, 2021 for assay results) (see Figure 3).

Figure 1 accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/f8889c88-2248-4428-baf1-f0a53e6c05fd

Figure 2 accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/143ddca2-2b69-44f2-9311-4524043d33dc

Figure 3 accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/d939bc82-fee4-4576-827c-af4295b76d4c

Figure 4 accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/d4758e71-9525-4969-a172-7477de18ec64

Table 1. Corner Bay Property Drill Assays Highlights from the 2021 Drill Program

1. The true width of the structures intersected is estimated at approximately 55-65% of the downhole width

Table 2. Previously Reported 2020 and 2021 Drill Assay Highlights from Main Vein below dyke (south)

1. True widths estimated to be 60%-65% of downhole lengths.
   

Corner Bay Deposit

The Corner Bay deposit contains an Indicated resource of 1.35 Mt at an average grade of 3.01% Cu and 0.29 g/t Au, containing 89.8 million pounds of copper and 13,000 ounces of gold, and an Inferred resource of 1.66 Mt at an average grade of 3.84% Cu and 0.27 g/t Au, containing 140.3 million pounds of copper and 15,000 ounces of gold, assuming a cut-off grade of 1.5% Cu and a copper price of US$3.25 per pound (Technical Report dated June 2019).

The Corner Bay deposit is hosted by the intrusive Lac Dor? Complex on the southern flank of the Chibougamau anticline. A regional north-northeastern diorite dyke also cuts the area. Several significant shear zones oriented north-south and northwest-southeast have been identified in the area. The Corner Bay area is characterized by copper porphyry style mineralization and by copper mineralization in shear zones commonly associated with dykes related to the Chibougamau Pluton.

The Main Vein is oriented N10?W dipping 75 to 85 degrees towards the west. To the north, the Main Vein is limited by one of the NW-SE structures while to the south it is open at depth across the "La Chib" fault. The mineralization varies from 15 centimeters to 8 meters thick, with an average thickness of 2.2 meters, located within a shear zone varying in width from 2 to 25 meters. The Main Vein below the dyke to the south is thicker and higher grade that the Main Vein above the dyke. The Main Vein lateral extension is now more than 900 meters and it remains open at depth down-dip and along strike (see Figure 4).

Additional drill holes in proximity to the Main Vein have intersected significant copper mineralization and will be included in the mineral resource estimate.

Drilling and Quality Control

The Company is using Miiken Drilling as the drilling contractor. Miiken is a joint venture between Chibougamau Diamond Drilling Ltd., the First Nations community of Ouje-Bougoumou and the First Nations community of Mistissini both located in the Eeyou Istchee territory.

Sample preparation and assays were done at SGS lab in Val-d'Or, Quebec. Samples were weighed, dried, crushed to 75% passing 2 mm, split 250 g, pulverized to 85% passing 75 microns. Samples were then fire assayed for Au (50 g) and sodium peroxide fusion ICP-MS finish for 34 elements.

QA/QC is done in house by Dor? Copper Geologists with oversight from the Exploration Manager. The check samples (blanks and standards - 4% of total samples with another 2% of core duplicates) that were inserted into the sample batches are verified against their certified values and are deemed a pass if they are within 3 standard deviations of the certified value. The duplicates are evaluated against each other to determine mineralization distribution (nugget). If there are large discrepancies in the check samples, then the entire batch is requested to be re-assayed.

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 provide an update on Corner Bay, its key asset for an eventual hub-and-spoke operation, at a webinar on Wednesday, July 7 at 12:00 PM EST.

To participate in the Town Hall Webinar, please register here with your full name:
https://zoom.us/webinar/register/WN_IUmKIZxoTs2vu3llhIlkqg

Corporate Update

Dor? Copper announces that all matters submitted to the shareholders for approval as set out in the Company's Notice of annual and special meeting (the "Meeting") and Information Circular which were mailed to shareholders in connection with the Meeting were approved at the Company's Meeting held in Thunder Bay, Ontario, on June 17, 2021.

The shareholders elected Mario Stifano (Executive Chair), Ernest Mast, Frank Balint, Joseph de la Plante, Sara Heston, Matthew Manson, and Brent Omland as directors of the Corporation for the forthcoming year. Shareholders also approved the Corporation's new omnibus share incentive plan and the appointment of Ernst & Young LLP, Chartered Professional Accountants, as auditor of the Corporation for the fiscal year 2021. Following the Meeting, Sara Heston was appointed Chair of the Audit Committee.

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 Dore/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 metres will be included in an updated mineral resource estimate expected for early Q3 2021. In addition, Dor? Copper is expected to have a maiden mineral resource estimate for the former producing Joe Mann mine (Au-Cu) by mid-July 2021.

For further information, please visit the Corporation's website at www.dorecopper.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 Dore/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).

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 Corner Bay drilling program increased to 30,000 meters, updating the mineral resource estimate for Corner Bay in early Q3 2021, delivering a PEA to support an eventual hub-and-spoke restart of the camp at the end of 2021, reaching a key target of 5 million tonnes of resources for Corner Bay, good continuity and increased thicknesses at depth at Corner Bay which lend itself to increased mining rates over time, Corner Bay's growth potential towards the south is open along strike and up-dip, assays received from six holes in the Main Vein above the dyke expected to increase the size of the resource at Corner Bay, implementing a hub-and-spoke development strategy by advancing the Corporation's key high-grade copper-gold brownfield projects towards a restart of operations, the Corporation's goal of achieving an annual production of 60 M lbs of copper equivalent (or 100,000 oz gold equivalent), and expecting a maiden mineral resource estimate for the former producing Joe Mann mine (Au-Cu) by mid-July 2021.

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.