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Adventus and Salazar report preliminary metallurgical results for El Domo VMS deposit

Published by , Assistant Editor
Global Mining Review,

Adventus Zinc Corp. (Adventus) and Salazar Resources Ltd (Salazar) (collectively the Partners) have announced the preliminary metallurgical results from composites collected from the 2018 infill drilling programme at the El Domo volcanogenic massive sulfide (VMS) deposit; which is part of the approximately 22 000 ha Curipamba project located near Las Naves, Ecuador. Results from the ongoing metallurgical testwork will be included in a Preliminary Economic Assessment (PEA), which shall also include an updated Mineral Resource estimate, in 2Q19.


Two metallurgical samples show positive results for the recovery of base and precious metals, and the production of saleable copper and zinc concentrates with results meeting or exceeding grades and recoveries derived from historical metallurgical testwork;

  • Mixed Composite Lock Cycle Test (LCT) results:
  1. In the copper concentrate, a copper grade between 22.4% and 24.7% was achieved with 79.2% to 86.3% recovery;
  2. A gold grade in the copper concentrate of 22.2 g/t to 23.6 g/t gold was achieved with 43.9% to 56.4% recovery;
  3. Gold recovery in the copper concentrate indicates a possible 24.7% increase from historically derived metallurgical recoveries;
  4. Copper recovery in the copper concentrate indicates a possible 10.8% increase from historically derived metallurgical recoveries;
  5. In the zinc concentrate, a zinc grade between 53.4% to 53.8% was achieved with 70.3% to 80.5% recovery, and;
  6. Both zinc grade and recovery in the zinc concentrate indicate a possible 11.6% and 30.5% increase respectively from historically derived metallurgical results.
  • Copper Composite LCT results:
  1. In the copper concentrate, a copper grade of 21.4% was achieved with 88.3% recovery, both of which are comparable to historically derived metallurgical results;
  2. A silver grade in the copper concentrate of 110.0 g/t was achieved with 50.2% recovery, and;
  3. Silver recovery indicates a possible 10.5% increase from historically derived metallurgical recoveries.

Christian Kargl-Simard, President and CEO of Adventus, commented: "The excellent metallurgical results from this round of testing show a substantial increase in all metal recoveries in the Mixed Composite, along with significantly improved concentrate quality. The Mixed Composite represents approximately 50% of the Mineral Resource, so this is a major milestone for the metallurgical performance of the El Domo VMS deposit that could have a materially positive impact on the future economics for the Curipamba Project. Our metallurgical team believes they can still improve on these results with follow-up work planned post our imminent PEA release."

Metallurgical testwork

For the most recent metallurgical testwork, the Partners adopted a strategy similar to the design of metallurgical composites from the historical PEA study completed for Salazar (see Salazar 22 January 2015 news release). 

Metallurgical composite samples were designed to produce commercial concentrates based on the relative abundance of base and precious metals in the feed material supplied from 2018 Phase 1 infill drilling at the El Domo VMS deposit that would be both spatially and volumetrically representative of the current open-pit constrained Mineral Resource estimate that has been classified in accordance with CIM (2016) Definition Standards – Disclosure for Mineral Projects.

The Indicated Mineral Resource totals 8.8 million t grading 1.62% copper, 2.34 g/t gold, 2.42% zinc, 48.0 g/t silver, and 0.27% lead. The Inferred Mineral Resource totals 2.6 million t grading 1.29% copper, 1.09 g/t gold, 1.51% zinc, 29.0 g/t silver, and 0.14% lead (see January 31, 2018 news release). The National Instrument (NI) 43-101 Technical Report was authored by Independent Qualified Person Dr. Lars Weiershäuser, P.Geo., of Roscoe Postle Associates Inc. (RPA), based in Toronto, Ontario, Canada, who is a Qualified Person as defined by NI 43-101.

Sample material was derived from the drill core assay coarse reject material that was vacuum sealed with a nitrogen purge after laboratory sample preparation and stored securely at Bureau Veritas (BV) facilities in Quito (Ecuador). A total of 1512 kg was shipped from storage to Base Metallurgical Laboratories Ltd. (BML), Kamloops, British Columbia, Canada, an independent laboratory, which is under contract for the metallurgical work. RPA is under contract to manage the metallurgical work and integrate its results into the upcoming PEA and Mineral Resource update.

Conventional rougher and cleaner flotation testing was completed on the composites and the selected optimum metallurgical settings for the composites were taken to LCT, which simulates the metal recovery process. Locked cycle testing indicates the expected metallurgical performance from the test materials that could result in the production of commercial concentrate material.

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