New Pacific Metals Corp. Reports Positive Results of Silver Sand Metallurgical Testing
Assessment ("PEA") released in January 2023, with the total sodium cyanide consumption being lower than the assumptions made in the PEA. Potential for recovery enhancement up to 93.9% for the second composite sample, through gravity concentration and regrinding, to be evaluated before finalizing the PFS. The metallurgical test program covered a broad range of characteristics including mineralogy, comminution, gravity concentration, cyanide leaching (utilizing both bottle roll and lifter bottle roll methods), and silver precipitation through zinc dust (employing the Merrill-Crowe process). Tailings testing encompassed evaluations of slurry characteristics (such as thickening, filtration,
and rheology), environmental factors, and the transportable moisture limit. Two life-of-mine and fourteen variability composite samples were used in the test program. Bureau Veritas's Metallurgical Division in Richmond (British Columbia, Canada), ALS Metallurgy in Kamloops (British Columbia, Canada), ALS Metallurgy in Perth (West Australia, Australia), SGS in Burnaby (British Columbia, Canada) and Pocock Industrial in Salt Lake City (Utah, USA) completed the work. Complete details and analysis of the metallurgical test program will be incorporated into the upcoming PFS. Below is a summary of additional technical details from the test program: The Bond ball mill work index and abrasion index generally align with PEA parameters. Oxide, transitional and sulfide materials all result in satisfactory silver recoveries. Continuous thickening tests for cyanide leach tailings achieved solid loading of 0.75 tonnes per hour per square meter and thickener underflow density of 66% solids. These two parameters outperformed PEA parameters. Several pressure filtration tests were completed for cyanide leach tailings. For the 60 mm chamber depth, filtration solid throughput was 142 tonnes per hour per square meter and the filter cake moisture content was 13.4%. These results generally align with PEA parameters. The measured transportable moisture limit was 13.5% on average. Preliminary cementation tests using zinc dust (Merrill Crowe) showed successful reduction of dissolved silver without any co-precipitation of dissolved copper. The efficiency of silver reduction was 98.4% ~ 99.9%.