Highlights of Ore Sorting Test
- Sample taken from the development mineralized material stockpiled at surface which was extracted during the preparation of the 2008 bulk sample
- Results indicate that the grade of the pre-concentrate tested with the ore sorter increased 2.6x, from 2.66% Cu to 6.84% Cu, with a recovery of 95.5% Cu by utilizing an X-ray transmission (XRT) sensor at Corem’s test facility in
Québec City - Reject material contained 62.8% of the initial mass and had a copper grade of 0.19%
- In practice, a higher recovery would be expected as fine materials from the mining and crushing operations would join the ore sorter pre-concentrate
Corner Bay mineralization is amenable to sorting and would have the following cost and environmental benefits:- Decrease in transportation costs and greenhouse gas emissions (GHGs) due to a reduction of transported material from mine to mill
- Decrease energy consumption at the mill due to the higher feed grade and hardness decrease of the feed material (lower Bond Work Index of the sorter pre-concentrate product compared to the feed)
- Reduce production of fine tailings
- Increase capacity of the mill to treat additional materials
Commenting on the results of our first sorting tests,
“As the implementation of ore sorting opens up new alternatives for the mill that require additional analysis, the Company is now planning to have the preliminary economic assessment (PEA) completed by the end of the first quarter of 2022. In addition, it will incorporate an updated mineral resource for
Ore Sorting Tests
A representative bulk sample was prepared by Doré Copper by selecting rocks from the development mineralized material stockpiled at surface from the project site. The material was selected to represent different rock types: semi and massive sulphides, shear zone, diorite dyke and anorthosite. At Corem’s facility, each rock type was crushed to less than 1 ½ inches (38 millimeters or mm) and screened at ¾ inch (19 mm). The fractions between 1 ½ inches and ¾ inches of each rock type were blended in different proportion to compose a representative bulk sample prior sorting. An industrial 1 m belt width COMEX OCXR-1000 integrated X-ray and optical sorting system was used and only the dual energy X-ray transmission (DE-XRT) sensor was used for the testing.
The ore sorting process helps concentrate the metals of commercial interest, which were principally associated with high density sulphide minerals. During this process, rocks were individually scanned, and low grade (low density) waste material is selectively diverted away from downstream processing. As a first step, the XRT sensor was calibrated with 100 different rocks representing all rock types and a calibration algorithm was developed for the
The sum of the three pre-concentrates represented 37.2% of the feed mass at a grade of 6.84% Cu and resulted in a cumulative copper recovery of 95.5%. The final reject portion represented 62.8% of the initial mass at a grade of 0.19% Cu representing 4.5% of the copper fed in the sorter. Fines from the crushing operation, grading 3.26% Cu, were not included in the ore sorting test. Some fines were generated, but as the rock types were crushed separately the crushing proportions were not considered for calculations. Therefore, in an operating application where the fine material fraction would join the pre-concentrate, the final pre-concentrate grade would be lower and the recovery would be higher than indicated by this test.
Potential Benefits of Ore Sorting
Sorting of the run-of-mine (ROM) material has the potential to reduce operating costs for milling, flotation and tailings management since it corresponds to a significant rejection of low-grade material. Sorting could decrease the hardness of the ore sent to the mill, and so, non-negligeable energy savings could be foreseen. The Bond Work Index (Wi) of the ore sorter pre-concentrate was determined to be 11.0 kWh/t by
Additionally, it is anticipated that potential savings in capital costs related to the smaller milling and flotation circuit would partially offset the costs associated with the ore sorter or provide capacity to treat additional material from other deposits in the region in the Copper Rand mill.
Based on the success of this first test, an ore sorting trade-off study will be integrated into the Company's upcoming PEA.
Qualified Persons
About
About Doré
Doré
The Corporation has consolidated a large land package in the prolific Lac Doré/
For further information, please contact:
President and Chief Executive Officer | Vice President, Investor Relations |
Phone: (416) 792-2229 | Phone: (416) 219-2049 |
Email: emast@Dorécopper.com | Email: lgaborit@Dorécopper.com |
For more information, please visit: www.dorecopper.com
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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
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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, higher copper recovery would be expected as fine materials from the mining and crushing operations would join the ore sorter pre-concentrate; expectations that ore sorting could also be successful at
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Source: DORÉ COPPER MINING CORP
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