Tawana Resources NL announced that larger scale metallurgical test work has delivered exceptional results which will allow for a simple, low-capital, low-risk startup operation and a short construction period for the planned commissioning at the Bald Hill Lithium and Tantalum Mine in October 2017.

 

Refer to the attached Joint Announcement in relation to metallurgical results at the Bald Hill Mine.

 

Highlights

 

&bull Larger scale metallurgical test work completed.

 

&bull Two key findings of Bald Hill mineralisation are:

 

        &bull The ability to produce grades well in excess of 6% Li2O at good mass yields and acceptably low iron content.

 

        &bull The ability to reject 60-70% of the feed mass after a first pass Dense Media Separation (&ldquo DMS&rdquo ), thus reducing processing costs appreciably.

 

&bull After removal of -1mm fines and mica, 78% of feed to the plant, containing 83% of the lithium, is available for low-cost gravity DMS processing.

 

&bull Recovery to immediately marketable concentrates from the DMS is 76.4% with an additional 21.8% reporting to secondary concentrates for future processing. This equates to about 129,000tpa of high grade coarse concentrate grading +6.4% Li2O at 1mtpa of feed.

 

&bull In addition, a total of 285,000t of fines and secondary concentrates, per million tonnes of feed, would be stockpiled for stage 2 processing or initially treated through the tantalum circuit.

 

&bull The benefits of the selected process route, for the stage one DMS circuit, are:

 

        - Low capital cost

 

        - Short time to commissioning, low risk

 

        - Very low processing cost

 

        - Production of a coarse high grade premium concentrate

 

&bull A circuit to treat the fines and secondary concentrates will be constructed after production commences and will be funded out of cash flow. This is expected to add ~45,000t of concentrate at limited incremental cost.

&bull The plan is to operate the existing tantalum plant concurrently with the DMS spodumene circuit adding significant by-product credits. This plant would be fed from fines from the DMS circuit and additional high grade tantalum mineralisation mined whilst mining lithium mineralisation.

 

&bull The DMS Feasibility study is well advanced with plant and infrastructure costings for the DMS circuit expected at the end of March.

 

&bull A 5 tonne sample is currently being processed to provide concentrate parcels for potential off-take partners.

 

&bull A number of off-take partners have visited the Project in the past few weeks and the company is currently advancing negotiations for offtake.

 

Study/Implementation progress

 

The processing content of the feasibility study was awarded to Primero Group, who are experienced lithium processing plant engineers and constructors. Primero have now finalised the plant flow sheet and developed a detailed 3-D model of the plant and site infrastructure. Plant and infrastructure costing is well advanced and will be available by the end of March.

 

Progress on 5-tonne sample

 

The companies have been approached by several potential off-take partners, all of whom have requested 40-80 kg parcels of typical concentrate to be produced at Bald Hill. It was decided to produce approximately 600-800kg of concentrate to satisfy these requirements, which in turn, required 4-5 tonnes of pegmatite to be processed. This material was obtained from existing pits.

 

This sample was crushed to 20mm and delivered to Nagrom Laboratory at the end of February. The sample will be further crushed to 10mm and processed according to the proposed plant flow sheet, and is expected to be completed before the end of March. The sample has a head grade of 2.14% Li2O.

 

Details on Metallurgical Results Following on from the excellent results obtained from the variability test work (refer ASX announcement on 13 February and SGX announcement on 12 February 2017), larger scale tests were done on a 160kg composite of core used in the variability tests.

 

The sample was crushed to 10mm and screened at 1mm. The -1mm fines have been retained for later testing. The +1mm fraction was further screened at 5.6 mm to assist the DMS gravity processing. The -5.6+1mm fraction was processed in a reflux classifier to remove mica, and then both -10+5.6mm and -5.6+1mm fractions were processed in a 100mm DMS cyclone.

 

These results demonstrated that the amount of fines produced was limited to 17% by coarse crushing at 10mm and that over 80% of the contained lithium was available for processing via the cheaper gravity DMS route.

 

These results highlighted two key characteristics of the Bald Hill mineralisation:

 

        &bull The ability to produce grades well in excess of 6% Li2O at good mass yields with acceptably low iron content.

 

        &bull The ability to reject 60-70% of the feed mass after a first pass DMS, thus reducing processing costs appreciably.

 

The product grade obtained in the coarser fraction using a density of 2.9 was over 7% Li2O and, whereas this is an excellent result, it is generally way above market requirements. Hence a lower medium density of 2.8 was adopted to increase the mass yield. This resulted in a mass yield of 17% at a grade of 6.3% Li2O at SG 2.8.

 

The middlings fraction, or 2.8 floats, still had a grade of 2.56% Li2O and a further test was done by re-crushing this to 3.35 mm to determine additional DMS recovery. This test resulted in a further mass yield of 4% at a grade of 6.14% Li2O to the sinks.

 

Tawana Resources is an JSE and ASX listed iron, gold and manganese exploration company with operations in Liberia and South Africa.