Mr. Adrian Lamoureux reports
92 RESOURCES CORP. SUCCESSFULLY COMPLETES DENSE MEDIA SEPARATION MINI-PILOT PLANT AND PRODUCES ~40 KG OF 6.11% LI2O SPODUMENE CONCENTRATE FROM HIDDEN LAKE
92 Resources Corp. has provided an update on the metallurgical program for the company's wholly owned Hidden Lake lithium project, Northwest Territories. The property is situated within the central parts of the Yellowknife lithium pegmatite belt, along Highway 4, approximately 40 kilometres east of Yellowknife.
The company is pleased to report that the recently announced (see news release dated Dec. 5, 2017) dense media separation (DMS) mini-pilot plant has been completed, with highly encouraging results. A total of about 400 kilograms of composited, whole-rock pegmatite material from Hidden Lake (pegmatites HL1, HL3, HL4 and D12) were processed during the pilot, producing over 40 kg of high-grade spodumene (1) concentrate averaging 6.11 per cent
lithium oxide (Li2O).
The DMS mini-pilot performed in line with expectations as indicated from the recent heavy liquid separation (HLS) testwork, whereby high-grade concentrate with low lithium loss to the tailings fraction was demonstrated. The testwork continues to support that a final overall concentrate grade of 6.0 per cent to 6.5 per cent Li2O at high recovery (80 to 85 per cent) is achievable using low-cost and conventional processing techniques.
A comparison chart of the HLS versus DMS results is found in the associated table.
LITHIUM HLS AND DMS GRADE (PER CENT LI2O) AND RECOVERIES PER FRACTION
Fraction Heavy liquid separation (HLS) Dense media separation (DMS)
Composite feed head grade 1.34% 1.36%
Concentrate grade 6.29% 6.11%
Concentrate recovery 56% 49%
Middling plus undersize (minus
0.85 millimetre) recovery 37% 43%
Loss to tailings 7% 8%
The assays for tantalum from the various DMS product streams are pending. However, once received, the deportment of the tantalum will be better understood and an approach for recovery further evaluated.
As a sufficient amount of the middling fraction is now available, batch flotation and locked cycle testwork on the combined DMS middlings and undersize fraction (minus 0.85 millimetre) will be completed shortly. This will provide for a complete and demonstrated base flowsheet with overall grade and recovery for the project. The flotation locked cycle testing will provide for more reliable data, as it effectively mimics, on a smaller scale, the recirculating streams of a flotation pilot plant operation.
The company currently has two applicable flowsheet approaches for the recovery of lithium-bearing minerals at Hidden Lake. The first involves a flotation-only circuit, where bench-scale testwork has demonstrated high-grade spodumene (1) concentrate (greater than 6 per cent Li2O), at high overall recovery (plus or minus 80 to 85 per cent), is achievable. The second involves a combination of flotation and DMS, with work to date strongly indicating a similar grade and recovery profile as that of flotation only approach.
Although high-grade concentrates at high recovery may be achievable and cost-effective using only flotation, a combination of dense media separation (DMS) and flotation is often the preferred approach for spodumene recovery from pegmatite for a variety of reasons -- typically more cost-effective to operate, easier to control, have a shorter operational start-up period as well as having overall less risk.
Target flowsheet and DMS mini-pilot plant
The base flowsheet being developed for the project comprises a crushing and classification circuit with the minus 0.85 mm fraction set aside, and the plus 0.85 mm fraction processed by DMS. This produces three streams -- concentrate, tailings and a middlings. The middlings are then combined with the minus 0.85 mm fraction, set aside earlier and processed by flotation, producing a second concentrate and tailings. The flotation concentrate is combined with the DMS concentrate to produce the final concentrate and overall recovery. This flowsheet is graphically presented on the company's website.
Whole-rock channel samples, collected from the recently completed 2017 summer field program, were used as feed material for DMS pilot plant. The work is being completed as part of the phase 2 beneficiation program, whereas phase 1 targeted the characterization of the material. The highly encouraging results of the phase 2 work to date are a direct result of the coarse-grained nature of the spodumene and its favourable liberation characteristics as indicated from the phase 1 work.
All testwork is being completed by SGS at its facility in Lakefield, Ont., and is being monitored by Dahrouge Geological Consulting Ltd.
(1) Montebrasite, a common lithium phosphate mineral, forms a minor component of the spodumene concentrate. Lithium from both spodumene and montebrasite has been demonstrated extractable at high recoveries.
National Instrument 43-101 disclosure
Darren L. Smith, MSc, PGeol, of Dahrouge Geological Consulting Ltd., a qualified person as defined by National Instrument 43-101, supervised the preparation of the technical information in this news release.
About 92 Resources Corp.
92 Resources is a modern energy solution company, focused on acquiring and advancing strategic and prospective modern energy-related projects. The company currently holds three principal assets in Canada: the Hidden Lake lithium property, in the Northwest Territories, the Corvette lithium property, in Quebec, and the Golden frac sand property, in British Columbia.
The Hidden Lake lithium property is strategically located within the heart of the Yellowknife pegmatite district with 2016 exploration results returning 1.90 per cent Li2O over nine m and grab samples up to 3.3 per cent Li2O.
The Corvette property consists of 76 claims, totalling 3,891 hectares, situated within the Guyer greenstone belt, which is also a favourable geological environment for gold occurrences.
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