Doré Copper boosts grade, recovery at Corner Bay by ore sorting

Doré Copper Mining (TSXV: DCMC; OTC: DRCMF; FSX: DCM) has tested sorting ore for its Corner Bay project, and both grade and […]
The Copper Rand mill will anchor an eventual hub-and-spoke mining strategy that includes the Copper Bay deposit. Doré Copper Mining photo






Doré Copper Mining (TSXV: DCMC; OTC: DRCMF; FSX: DCM) has tested sorting ore for its Corner Bay project, and both grade and recovery got significant boosts. The Corner Bay copper-gold deposit is about 55 km by road from the company’s Copper Rand mill near Chibougamau, Que.  

The copper grade of ore for the mill feed rose 77% to 3.93% from 2.20% copper. The potential copper recovery rate was 93.6% in tests. The reject material after sorting contained 48% of the initial mass and had a copper grade of 0.30%. 

Gold, silver, and molybdenum grades also received a boost. The gold grade went up to 0.29 g/t from 0.17 g/t; the silver grade went to 13.82 g/t from 7.91 g/t; and the moly grade rose to 0.064% from 0.037%. 

Doré says sorting also reduced the arsenic content of the two pre-concentrates to only 12 ppm, which leads to a very clean final concentrate level. 

Tests were conducted at the Steinert ore sorting facility in Kentucky. 

The minimal amount of fines generated during the tests was not considered in the calculations. In practice, the fines from mining and crushing will join the pre-concentrate in the ore sorting circuit and would have an additional positive effect on recovery. 

The company released a preliminary economic assessment for Corner Bay in May 2022. Using a copper price of US$3.75/lb. and a gold price of US$1,820/oz., the project is expected to have an all-in sustaining cost of US$2.24/lb. copper-equivalent. The mine would have a life of 10.5 years with average annual copper-equivalent production of 53 million lb. in concentrate. Costs were estimated at $204.4 million for capex and $180.6 million for opex. 

Measured and indicated resources for the Corner Bay, Devlin, and Joe Mann deposits total 3.5 million tonnes grading 2.55% copper and 0.25 g/t gold. There are 194.0 million lb. of copper and 27,000 oz. of gold to be recovered. The inferred resource for the three deposits is 6.9 million tonnes grading 3.04% copper and 0.83 g/t gold. 

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