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Sovereign Metals: Testwork Validates Malingunde Flowsheet and Identifies Potential for Additional Plant Feed

Sovereign Metals Limited (“the Company” or “Sovereign”) is pleased to provide an update on the progress of the Pre-feasibility Study (“PFS”) for the low cost Malingunde Saprolite-Hosted Graphite Project (“Malingunde Project” or “the Project”).

The Company has undertaken a substantial metallurgical test-work program for the front end of the proposed graphite processing plant at Malingunde, which validates the use of a high-energy scrubber with media addition (as opposed to a primary crusher and mill) to disaggregate the soft saprolite material, followed with a conventional downstream flotation circuit.

Further, the test-work has identified the ability to process the more competent saprock (beneath the very soft saprolite) with the addition of a small recycle pebble crusher to the circuit. This should enable the Company to access substantial additional mineralised material previously not considered in the 2017 Scoping Study production target.

HIGHLIGHTS:

-          All weathered material types (saprolite & saprock) show good amenability to the modified flowsheet.

-          The ability to process oversize scrubber product through a small pebble crusher enables the potential for saprock material to be included as additional plant feed.

-          At a proposed feed blend of 85% saprolite and 15% saprock, only a minimal portion of the total feed material will require additional comminution through the recycle pebble crusher.

-          Concentrates produced from a range of composites and drill core intervals give a weighted average recovery of ~89%, TGC grades ranging between 96% and 98% and flake size distributions averaging ~60% >150µm (all weighted on weathering types within the geology model).

-          The updated Malingunde JORC Mineral Resource is expected to be delivered in early June.

Sovereign’s Managing Director Dr Julian Stephens commented, “These metallurgical results confirm that Malingunde saprolite ores can be processed using a simple comminution circuit. Additionally, the ability to blend and process the more competent saprock with the simple addition of a small pebble crusher is a fantastic outcome, enabling the Company to access additional material previously not considered as part of the Malingunde Scoping Study production target.”

ENQUIRIES   Dr Julian Stephens – Managing Director

+618 9322 6322  Dominic Allen – Business Development Manager

SCRUBBER TESTWORK

The very soft nature of the Malingunde saprolite-hosted material indicated that it would be amenable to low cost scrubbing as opposed to more traditional crushing and milling required for hard rock deposits. As part of the Malingunde PFS, a scrubber test-work program was designed to validate the front-end process flowsheet.  The test-work was undertaken by ALS Global in their Perth laboratory. 

Four weathering types (mottled saprolite, upper saprolite, lower saprolite and saprock) and a blended master composite were tested. Optimal results were achieved with the addition of a small amount of media to achieve a scrubber power input of 2.5kWh/t.  Key results include;

-          93% of master composite reduced to the required rougher flotation size of -2mm in a single pass

-          68% of saprock composite reduced to the required rougher flotation size of -2mm in a single pass

To ensure a robust circuit capable of handling a range of materials, including the more competent saprock, the proposed plant circuit will include a recycle pebble crusher for the coarse scrubber product. Material between 2mm and 10mm is recycled directly back through the scrubber, whilst +10mm oversize is processed through the pebble crusher. This will ensure all scrubber feed material reports to the flotation circuit.

At the proposed feed blend of 85% saprolite and 15% saprock, a relatively minor portion of the total feed material is recycled back through the scrubber, with only a small part of this processed through the recycle pebble crusher.

Figure 1: Images of +300µm fraction of scrubber product from Master Composite (top L) and Saprock (top R) showing well liberated graphite flakes amongst quartz-dominant gangue. +500µm super-jumbo flake final concentrate (bottom L) and +150µm medium flake final concentrate (bottom R).

FLOTATION TESTWORK

The PFS flotation test-work program is being undertaken by SGS Canada, with the program split into three components; an optimisation program, a variability program and a set of larger scale batch tests to generate concentrates for potential customers and further downstream test-work. The optimisation program using a master scrubber composite has been completed, with variability and large-scale batch tests ongoing and planning to be completed in the coming weeks.

The optimisation program focused on float densities, polishing and attritioning mill types and media, polishing times and overall flotation residence times.

The flotation results to-date on a range of test samples have confirmed the very robust metallurgical characteristics of the Malingunde saprolitic material (saprolite and saprock), with very good amenability to produce high grade, coarse flake graphite products with minimal effort.  Final concentrates average approximately 60% weight in the +150µm fractions with graphitic carbon content in the 96% to 98% range (all weighted on weathering types within the geology model).

PFS UPDATE

The PFS program is on schedule for completion in July with the pit optimisations completed and the mine design and final scheduling in progress. A request for budget quotation was sent out to a number of mining contractors, with the information provided used to generate mining costs. An owner-operator mining option will also be analysed as part of the PFS.

The plant design using the optimised results from the metallurgical test-work program has been completed and the equipment is currently being costed.  Layouts are in progress and the non-process infrastructure is being finalised. 

The tailings storage facility (TSF) design is in progress with sequential lifts being planned based on the availability of waste rock from the mine.  Alternative options for future TSF lifts to reduce life-of-mine costs are being investigated including cycloning of tailings for wall building and in-pit disposal of tailings when pits have been depleted.

Baseline studies for the environmental and social impact assessment (ESIA) will be completed in the coming months, with the major focus having been upon social activities including stakeholder engagement and resettlement action plan. The ESIA Scoping Study report has been updated with the results from the stakeholder engagement and has been submitted to the Malawian regulators. The ESIA program is scheduled for completion by the end of 2018.

Competent Person Statements

The information in this report that relates to Metallurgical Testwork Results is based on information compiled by Mr Kelvin Fiedler who is a Member of the The Australasian Institute of Mining and Metallurgy. Mr Fiedler is a consultant of Mineral Processing Consultants Pty Ltd.  Mineral Processing Consultants Pty Ltd is engaged as a consultant by Sovereign Metals Limited. Mr Fiedler has sufficient experience, which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking, to qualify as a Competent Person as defined in the 2012 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves'. Mr Fiedler consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.

Forward Looking Statement

This release may include forward-looking statements, which may be identified by words such as "expects", "anticipates", "believes", "projects", "plans", and similar expressions. These forward-looking statements are based on Sovereign’s expectations and beliefs concerning future events. Forward looking statements are necessarily subject to risks, uncertainties and other factors, many of which are outside the control of Sovereign, which could cause actual results to differ materially from such statements. There can be no assurance that forward-looking statements will prove to be correct.  Sovereign makes no undertaking to subsequently update or revise the forward-looking statements made in this release, to reflect the circumstances or events after the date of that release.

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