Doré Copper Reports High-Grade Gold Mineralization at Gwillim

Drilling Highlights

KOD-21-02

• 3.33 g/t Au over 13.3 meters, including 26.8 g/t Au over 1.0 metre and 23.2 g/t Au over 0.5 meter
• 3.39 g/t Au over 3.0 meters
• 10.14 g/t Au over 4.0 meters
  

KOD-21-03

• 3.03 g/t Au over 4.0 meters
• 4.64 g/t Au over 6.0 meters, including 11.69 g/t Au over 2.0 meters

Ernest Mast, President and CEO of Dor? Copper, commented, "Today's results on the Gwillim's KOD zone demonstrate good continuity of the mineralization and have extended its depth to 400 meters vertical. We are in the process of compiling and re-evaluating all the historical data for the Gwillim mine and the KOD zone. Once completed, we and our JV partner Argonaut Gold Inc. will plan a drilling program to test the strike and depth extension of both deposits. On our main deliverable for the year, we expect to have the results of the preliminary economic assessment (PEA) for our hub-and-spoke operation model by mid-Q2 2022."

Gwillim Drilling Program

Dor? Copper drilled two holes in September 2021 to test the KOD zone, located 300 meters south of the mined Gwillim Main zone (Figure 1 and Table 1). Hole KOD-21-02 intersected three mineralized zones, including a 13.3 meter zone grading 3.33 g/t starting at a vertical depth of approximately 25 meters and an intercept of 4.0 meters at 10.14 g/t Au, which is interpreted as the KOD zone. Hole KOD-21-03, drilled 100 meters north-northwest of KOD-21-02, intersected two mineralized zones and demonstrated the continuity of the KOD zone at depth (Figure 2). The second mineralized zone, 6.0 meters at 4.64 g/t Au extended the KOD zone vertically by approximately 50 meters from prior historical intercepts (historical drill holes locations are approximate and will be georeferenced in the coming months) and is the deepest intersection to date at a vertical depth of 400 meters.

Gwillim Property

The Gwillim property totals 486 ha. The western part of the property (385 ha) is under a 50/50 joint venture between Dore Copper and Argonaut Gold Inc. (through its wholly owned subsidiary Prodigy Gold Inc.) with Dore Copper being the operator. The eastern part of the property (102 ha) is 100% owned by Dore Copper.

Located on the joint venture land, the Gwillim mine operated between 1974 and 1976 and again from 1980 to 1984. In total 254,066 short tons were mined at a grade of 4.79 g/t Au¹. Most of the production came from the Main zone, which extended along strike for 122 meters with an average width of 2.6 meters and up to a depth of 114 metres.

In 1987, two high-grade intercepts of 7.0 meters at 33 g/t Au and 7.9 meters at 17.9 g/t Au were drilled by Greenstone Resources Ltd. at moderate depths of 200 to 300 meters at the KOD zone (300 meters south of the mined Gwillim Main zone)². A further 25 holes were drilled from the surface before a ramp was developed and the zone was further explored from underground in 1988 but not mined (some development through ore). In 1989, three more surface holes were drilled to depths of 400 meters with one hole confirming the extension of the high-grade mineralization beyond 300 meters vertical depth. An internal report from 1989 outlined a small historical resource (not NI 43-101 compliant) for the KOD Zone. No other significant exploration activities are reported after this work.

Gwillim is hosted within the Roy group in the Bruneau Formation, in pillowed basalts and gabbroic sill. Mineralization is hosted predominantly within east-west, steeply dipping structures containing quartz-carbonate veins with limited amounts of massive sulphides. At KOD, there are two parallel east-west vein zones, approximately 50 meters apart, with the mineralization predominantly occurring in the northernmost vein. The thickness of the mineralization varies between 0.3 and 5.0 meters. The KOD zone is open along strike and downdip to the east under the Gwillim lake.

References:
¹ Structural and Stratigraphic Control on Magmatic, Volcanogenic, and Shear Zone-Hosted Mineralization in the Chapais-Chibougamau Mining Camp, Northeastern Abitibi, Canada - Leclerc et al., 1992 Society of economic geologist inc. V 107, pp. 963-989.
²Diamond Drilling Report on the Gwillim Lake KOD Zone, Greenstone Resources (internal report) - Robert McIntosh, Project Geologist, Flanagan McAdam and Company, December 1989.

Table 1. Gwillim Assays Highlights from the 2021 Drill Program

1. The true width of the structures intersected is estimated at approximately 55-60% of the downhole width.
   

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 was done at SGS Canada Inc. in Val-d'Or, Qu?bec, fire assay and ICP analysis was done at SGS Canada Inc. in Burnaby, B.C. Samples were weighed, dried, crushed to 75% passing 2 mm, split to 250 g, and 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.

Figure 1. Surface plan of a portion of the Gwillim Property showing the location of the 2021 drill holes.
https://www.globenewswire.com/NewsRoom/AttachmentNg/3ccbfb99-565e-41b7-8a6f-47949565b469

Figure 2. Cross-section of the KOD zone showing holes KOD-21-02 and 03.
https://www.globenewswire.com/NewsRoom/AttachmentNg/c906d708-c634-408d-a409-284209c36268

Qualified Person

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. aims to be the next copper producer in Qu?bec with an initial production target of +50 Mlbs of copper equivalent annually by implementing a hub-and spoke operation model with multiple high-grade copper-gold assets feeding its centralized 2,700 tonnes per day mill. The Corporation is expected to deliver a PEA by mid-Q2 2022 and then initiate a feasibility study and permit applications.

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 gold ³. The land package includes 13 former producing mines, deposits and resource target areas within a 60-kilometre radius of the Corporation's Copper Rand Mill.

For further information, please contact:

Visit: www.dorecopper.com
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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 and its JV partner Argonaut Gold Inc. planning a drilling program to test the strike and depth extension of both deposits; aiming to be the next copper producer in Qu?bec with an initial production target of +50 Mlbs of copper equivalent annually; PEA by mid-Q2 2022; implementing a hub-and spoke operation model; and initiating a feasibility study and permit applications after the PEA.

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