New Pacific Metals (TSX:NUAG, NYSE:NEWP) Corp said it expects to advance its flagship Silver Sand project in Bolivia as a low-cost, open-pit heap leach operation following the results of latest metallurgical testing.
The heap leach process showed 80% recovery and is a superior option due to the expected lower capital intensity and operational costs compared to alternatives to produce silver doré on site, said New Pacific.
The material tested in the 2020- 2021 program was created from over 300 samples from four metallurgical holes. Three master composite samples were created with grades ranging from 90 grams per ton (g/t) to 120 g/t silver of oxide, transitional (oxide-sulphide) and sulphide (fresh) mineralization, together with six grade variability composites.
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Heap leach column testing, coarse bottle roll testing and flotation test work was carried out, and studies showed that a heap leach operation was "significantly superior to all other modeled options".
"The positive results from this metallurgical program, combined with the results from the 2019 Metallurgical Study, significantly de-risk the Silver Sand Project," said Dr Mark Cruise, the CEO of New Pacific, in a statement.
"We anticipate the project will move forward as a low-cost, open-pit heap leach operation. The Preliminary Economic Assessment (PEA) for the Silver Sand Project, including an updated Mineral Resource Estimate, is expected to be published in first half of 2022 and will incorporate results from our current 38,000-metre resource expansion drill program," Cruise added.
The company said that further work will focus on optimizing the heap leach process flowsheet and acknowledged that significant growth in the sulphide component of the resource could change the comparative modelling results and subsequent potential implications of future test work.
This could potentially lead to a Phase II processing solution in the contemplated life-of-mine operation plan, it said.
It also noted that a further 115kg of drill core coarse reject material had been delivered to SGS Lima for -2mm coarse bottle roll variability test work.
"The results will be used to refine the relationship between the oxidation state of the mineralization and the silver recovery in the transitional and sulphide components of the Mineral Resources. This data will also help refine the selection of composites for future anticipated prefeasibility-level column leach tests," it said.
New Pacific is advancing precious metal projects in Bolivia and has the flagship Silver Sand project, the Silverstrike project and the Carangas project.
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