Excellent concentrate grades and recoveries with low impurity

Dore Copper reports excellent concentrate grades and recoveries with low impurity element concentrations from flotation tests at its Corner Bay project

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Toronto, Ontario October 30, 2023 – Doré Copper Mining Corp. (the “Company” or “Doré Copper“) (TSXV: DCMC; OTCQX: DRCMF; FRA: DCM) is pleased to announce positive flotation test results at its flagship Corner Bay high-grade copper-gold project located approximately 55 kilometers by road from the Corporation’s Copper Rand mill, near Chibougamau, Québec. This metallurgical test program is part of the work that is designed to support completion of a feasibility study for the implementation of a hub-and spoke operation model.

Key Highlights from “Lock Cycle” Flotation Tests

  • Excellent copper recoveries of 98.2% and 96.8% from a representative composite sample
  • High-quality copper concentrate grades results of 27.0% and 29.6% 

The results are an improvement over the figures included in the May 2022 preliminary economic assessment (“PEA”), where the flotation recoveries for copper were 96.7% and the copper concentrate grade was 23.7%. All metallurgical tests completed to date support the effectiveness of utilizing ore sorting technology to improve the mill feed grade and reduce the mill feed tonnage resulting in a high-quality salable copper concentrate.

Ernest Mast, President & CEO, stated, “These flotation test results validate the favorable mineralogy of the Corner Bay deposit for high performance ore sorting technology and conventional flotation to produce a high-quality copper concentrate containing low levels of deleterious metals. These figures demonstrate the robust nature of the processing plant flowsheet that will be used in the feasibility study.” 

Metallurgical Test Work Program Summary

Base Metallurgical Laboratories in Kamloops, British Columbia was commissioned to complete Corner Bay metallurgical development and locked cycle flotation testing in support of the feasibility study.

A total of 34 diamond drill holes were used to create a spatially diverse composite sample (the “CBSP” composite) that intersected copper mineralized zones within the Corner Bay Mineral Resource estimate.  The core material selected represented different rock types: semi and massive sulphides, quartz veins, diorite dyke, and fresh and altered anorthosite. The drill core was sampled by cutting a quarter split NQ core.  

The CBSP composite was firstly compiled into a 202 kilogram sample with a grade of 2.20% Cu. The CBSP composite was then processed through the Steinert ore sorter and mixed with 26% of the unsorted underflow by-passed mineralized material to represent an overall sorted pre-concentrate mineralized material product. The CBSP composite resulted in a 123 kilogram sample with a grade of 3.31% Cu.

The composite sample was evaluated through lock cycle tests to determine the flotation metallurgical performance.  The sample was prepared to a nominal grind size of 140 microns K80 in the rougher testing and then processed through a regrind size of approximately 37 microns K80 in the cleaner tests. 

The sample responded consistently throughout the test work with excellent performance to conventional flotation processing methods and reagents. Two locked cycle tests were completed with varying retention times to determine the concentrate grade versus recovery. The tests resulted in concentrate grades of 27.0% Cu and 29.6% Cu and recoveries 98.2% and 96.8%, respectively (see Table 1).  

Minimal amounts of deleterious elements (e.g. arsenic, antimony, bismuth, cadmium etc.) were present in the concentrate, indicative of the “clean” nature of the concentrate (see Table 2). These results showed the highly commercial quality of the concentrate in terms of salability and payment terms of smelters. 

Table 1. Metallurgical Test Work Results

Composite / TestLock cycle test feedConcentrate Recovery
CBSP (sorted mineralized material)Cu %Au g/tAg g/tCu %Au g/tAg g/tCu %Au %Ag %
Lock Cycle Test 13.310.30927.01.826898.272.186.4
Lock Cycle Test 23.280.551029.63.247296.862.676.9

Table 2. Impurity Element Content of Copper Concentrate

Composite / TestImpurity Elements (ppm)1
CBSP (sorted mineralized material)Arsenic (As)Antimony (Sb)Bismuth (Bi)Cadmium (Cd)Lead (Pb)Mercury (Hg)Zinc (Zn)
Lock Cycle Test 12234101021735
Lock Cycle Test 2103310881777
1. All analyses in parts per million (ppm).

Technical Disclosure

All metallurgical test work referenced in this news release was completed by Base Metallurgical Laboratories Ltd. (“BML”), based in Kamloops British Columbia, Canada.

Commercial certified standard material and blanks were inserted by BML into the sample chain accounting for 10% of the samples as part of the quality assurance and quality control (QA/QC) program. 

Qualified Person

Ernest Mast, P.Eng., President and CEO of the Corporation, and a “Qualified Person” within the meaning of National Instrument 43-101 – Standards of Disclosure for Mineral Projects, has reviewed and approved the scientific and technical information contained in this news release.

About Doré Copper Mining Corp. 

Doré Copper Mining Corp. aims to be the next copper producer in Québec 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 Copper Rand mill1. The Company has delivered its PEA in May 2022 and is proceeding with a feasibility study. 

The Company has consolidated a large land package in the prolific Lac Doré/Chibougamau and Joe Mann mining camps that has historically 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 Copper Rand Mill. 

For further information, please contact:

Ernest Mast 
President and Chief Executive Officer
Phone: (416) 792-2229

Laurie Gaborit
VP Investor Relations
Phone: (416) 219-2049

For more information, please visit: www.dorecopper.com 

Facebook: Doré Copper Mining
LinkedIn: Doré Copper Mining Corp.
Twitter: @DoreCopper
Instagram: @DoreCopperMining

  1. Technical report titled “Preliminary Economic Assessment for the Chibougamau Hub-and-Spoke Complex, Québec, Canada” dated June 15, 2022, in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects. The Technical Report was prepared by BBA Inc. with several consulting firms contributing to sections of the study, including SLR Consulting (Canada) Ltd., SRK Consulting (Canada) Inc. and WSP Inc. 
  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 François 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). Doré Ramp November 1992 Summary, internal Westminer Report. 

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. All statements other than statements of historical fact included in this news release, including, without limitation, statements with respect to the timing and ability of the Company to receive necessary regulatory approvals, the Company’s ability to meet its production target, the commencement, timing and completion of a feasibility study, and the plans, operations and prospects of the Company 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 Company with securities regulators. Although the Company 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 Company 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.