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Aftermath Silver’s Berenguela Metallurgical Test Work Achieves 99.9% Pure Battery Grade Manganese Sulphate Monohydrate

February 29, 2024

Aftermath Silver Ltd.


Aftermath Silver Ltd. is pleased to announce that the initial metallurgical work on a high manganese drill core composite sample of silver-copper-manganese mineralization from its Berenguela project in Peru, carried out at Kappes Cassiday and Associates’ (KCA) Reno facility, has successfully produced battery grade 99.98% pure manganese sulphate crystals which assayed 31.9% Mn (High purity manganese sulphate monohydrate or “HPMSM”). The test work involved only hydrometallurgical processes and no electrowinning was required for purification. The tables below contain results for the head assay grade of the composite test sample and the final MnSO4 analysis.

High Purity MnSO4.H2O Analysis

98002 <1<11<18.0< 1.0<131.4<1<1<1<1<1<1
98002 <110.531.9<136.81.3<1<1<13.6<1<1<13.3

Composite Sample of Mineralization, Average Head Assay Grade


KCA is still carrying out testwork hence it’s not possible to currently give an accurate Mn recovery, however they estimate that Mn recovery is likely greater than 90% in the flow sheet used in this testwork.

Ralph Rushton, President of Aftermath commented: “In a significant first for the Berenguela project, this bench-scale work has recovered high purity battery grade manganese sulphate with less than 150ppm impurities. A photo of the crystallised MnSO4 is included below. KCA’s on going metallurgical testwork on Berenguela will also focus on validating their  historic work which recovered silver dore, copper metal and zinc sulphide from the mineralization.

Ralph Rushton, President, CEO and Director, Aftermath Silver Ltd.

With the unprecedented projected growth in electric vehicle production, battery grade manganese sulphate is playing a significant role. Coupled with the changing battery chemistries that are now substituting manganese for cobalt, the market and pricing for battery grade manganese sulphate has increased to the point where manganese- along with silver and copper- could play a significant role in the Berenguela economics as we advance the project toward a preliminary economic assessment (PEA).

Although test work has not been completed, KCA has indicated that recovery of high percentages of copper and silver are potentially achievable using a simple flowsheet compatible with that used for the recovery of the manganese sulphate. Silver is a critical mineral in the manufacture of solar panels, and copper is a critical “green energy” metal. We now plan to perform the same test work on different composite samples from Berenguela, and to scale up the tests and advance toward the PEA. I’d like to thank KCA’s technical team for their excellent work in demonstrating that Berenguela can potentially produce a battery grade manganese sulphate product at this level, and we look forward to the results from future metallurgical test work.”

What Is Manganese Sulphate Monohydrate?

Battery grade manganese sulphate monohydrate is a pale pink inorganic chemical, with the formula MnSO4.H2O, in demand as a source of manganese for the battery manufacturing industry. Pure crystals of MnSO4.H2O contain approximately 32% manganese and one tonne of manganese metal should theoretically yield approximately 3 tonnes of MnSO4.H2O.  Most MnSO4.H2O is produced by reducing the mineralization to metal, then dissolving the metal in acid.  The process developed for Berenguela is simpler and less energy intensive – the mineralization is directly processed with acid to dissolve the manganese and other metals. The solution is purified, then the manganese sulfate is directly crystallized. China currently accounts for roughly 90% of global high purity MnSO4.H2O production so potential new sources of sulphate outside of China are becoming strategically and commercially important.

Figure 1. Battery grade crystallised MnSO4 prepared by KCA from Berenguela composite sample.

KCA’s Test Work

The current test program is building on previous metallurgical work carried out by KCA in 2010. Details of the historic test flowsheets and results are summarised in Section 13 of the Aftermath Technical Report “Berenguela Mineral Resource Estimate NI 43-101 Aftermath Silver Ltd. Province of Lampa, Department of Puno, Peru”, dated March 30, 2023, prepared by AMC Consultants available here or on Aftermath’s website at the link below:


Investors are cautioned that this is historical metallurgical work that Aftermath has not yet fully validated and it should not be relied on. However, KCA is currently duplicating much of the historic work on behalf of AAG and the results to date suggest that the historic work is repeatable and was done to a high standard.

Sixteen composite samples weighing over 6 tonnes in total were selected from Aftermath’s metallurgical drilling program and delivered to KCA’s laboratory in Reno. The composites represent the key geometallurgical domains which cover all mineralization types encountered and form the basis of the current metallurgical processing campaign. Test work is being performed individually or on blends of the samples. The objective of the current program, which complements and partly repeats the historic metallurgical test work, is to refine the flowsheet routes and to outline approximate plant costs for a planned preliminary economic analysis (“PEA”). The work includes:

  • crushing and splitting;
  • pressure filtration tests;
  • creation of a standard solution for subsequent processing steps;
  • removal of iron from primary leach solution;
  • leach tests to determine the conditions (oxidation, cyanide level & consumption, leach time) for optimum silver recovery;
  • SX/EW tests for recovery of copper from the primary leach solution;
  • sulphide precipitation and recovery of zinc;
  • characterization of purified solution to identify other trace impurities and remove them if necessary;
  • MnSO4 crystallization processes and preparation of MnSO4 to send to outside groups for evaluation.

Berenguela Resource Estimate

In March 2023, Aftermath published an updated resource estimate for Berenguela which included manganese in addition to substantial silver and copper resources across the Measured, Indicated and Inferred categories. Mineral Resources are stated at a cut‐off grade of 80 g/t silver equivalent. The relative value in the Mineral Resource by metal is as follows, Ag=26%, Mn=44%, Cu=26%, Zn=4%, however the estimate used pricing for agricultural grade MnSO4 which trades at a considerable discount to battery grade manganese sulphate. The model is depleted for historical mining activities. Please refer to Aftermath Technical Report “Berenguela Mineral Resource Estimate NI 43-101 Aftermath Silver Ltd. Province of Lampa, Department of Puno, Peru”, dated March 30, 2023, prepared by AMC Consultants available here or on Aftermath’s website at the link below:


Berenguela Ag-Cu-Mn deposit Mineral Resource as of 31 January 2023

Resource ClassificationTonnage MtGradeContained Metal
Measured and Indicated40.176786.100.670.34101.22.45589.0299.3


  • CIM Definition Standards (2014) were used for reporting the Mineral Resources.
  • The effective date of the estimate is 31 January 2023.
  • The Qualified Person is Dinara Nussipakynova, P.Geo., of AMC Mining Consultants (Canada) Ltd.
  • Mineral Resources are constrained by an optimized pit shell using the assumptions in Table 2.
  • No dilution or mining recovery applied.
  • Cut-off grade is 80g/t AgEq.
  • Bulk density used was estimated and variable. but averaged 2.30 tonnes/m3 for mineralized material and 2.25 tonnes/m3 for waste.
  • Drilling results up to 13 October 2022.
  • Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
  • The numbers may not compute exactly due to rounding.
  • Mineral Resources are depleted for historic mined out material.
  • The relative value in the Mineral Resource by metal is as follows, Ag=26% Cu=26%, Mn=44%, Zn=4%.

Source: AMC, (2023).


All sample preparation and assaying were carried out in Reno, Nevada by Kappes, Cassiday & Associates. Head sample assays were performed on ICP-OES by standard 4-acid digestion. All digestions were run in parallel with OREAS certified reference materials. Ag content in the head samples were QC’d by fire assay for verification. A suite of 28 elements were tested in the head samples and on all subsequent assays.

After dissolution of the mineralization, and following each purification step, all solutions were analyzed by ICP-OES. After all trace impurities were removed, solutions were subjected to evaporative crystallization yielding MnSO4.H2O (HPMSM) crystals. The solution which was evaporated to produce the crystals was analyzed (prior to crystallization) to confirm that there were no elements in solution which were above the allowable levels for HPMSM listed impurities.  Crystals were then dried for 48 hours to remove residual water. To verify purity, crystals were dissolved in water and re-analyzed. These analyses confirmed that the crystals were wthin spec for all listed elements.

Qualified person

Michael Parker, a fellow of the AusIMM and a non-independent director of Aftermath, is a non-independent qualified person, as defined by National Instrument 43-101. Mr. Parker has reviewed the technical content of this news release and consents to the information provided in the form and context in which it appears.

Dan Kappes, a Registered Professional Engineer (Mining Engineer #3223, Metallurgical Engineer #3223) in the State of Nevada, USA, and Founder and President of Kappes, Cassiday & Associates, is the qualified person set out in National Instrument 43-101 (NI 43-101) responsible for overseeing the design and execution of the metallurgical test program and has reviewed and approved the contents of this release.

About Aftermath Silver Ltd.

Aftermath Silver is a leading Canadian junior exploration company focused on silver and aims to deliver shareholder value through the discovery, acquisition and development of quality silver projects in stable jurisdictions. Aftermath has developed a pipeline of projects at various stages of advancement. The company’s projects have been selected based on growth and development potential.


Ralph Rushton”

Ralph Rushton
CEO and Director

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