Dakota Minerals - Encouraging Metallurgical Results from Lynas Find Li Project

Dakota Minerals - Encouraging Metallurgical Results from Lynas Find Li Project

Dakota has positive results from its metallurgical testing on diamond drill core from the Lynas Find lithium project in the Pilbara. Spodumene-bearing pegmatite zones in 2 holes were sampled for “sighter” metallurgical tests and analysis showed high grades and good repeatability with nearby RC twin holes. The core was then subjected to comminution & beneficiation tests, where Heavy Liquid Separation work produced a high grade spodumene product grading 6.56% Li2O, equating to 90.6% Li2O recovery.


 

Highlights

Highly encouraging results from initial metallurgical testwork on Lynas Find diamond core with good Diamond v RC grade correlation:

  • High grade (6.56% Li2O) spodumene mineral concentrate produced using Heavy Liquid Separation (HLS), achieving 90.6% Li2O recovery from diamond core material
  • Diamond holes twinning existing RC holes yielded high grade intercepts of 16.6m @ 2.47% Li2O from 8.4m, and 24.9m @ 2.16% Li2O from 17.1m depth.

Maiden resource at Lynas Find imminent.

Dakota Minerals Limited (“Dakota”, “DKO”, or “Company”) is pleased to provide an update on its metallurgical test work programme, carried out on diamond drill core from the Lynas Find lithium project.

The programme represents the next stage of Dakota’s strategy to advance the Lynas Find project in the Pilbara region of Western Australia, which is progressing in tandem with its European lithium strategy.

Spodumene-bearing pegmatite zones in two diamond drill holes from the Lynas Find Central pegmatite were sampled and sent to SGS Metallurgy in Perth for “sighter” metallurgical test work to progress knowledge of the ore. Analysis of the drill core showed high grades and good repeatability with nearby RC twin holes. The core was then subjected to comminution and beneficiation testwork, in order to trial optimal ore processing techniques. During the beneficiation testwork, Heavy Liquid Separation (HLS) tests were shown to work very well with the Lynas Find ore, producing a high grade spodumene product grading 6.56% Li2O, equating to 90.6% Li2O recovery. These results indicate that dense media separation (DMS) would be a viable processing route for the Lynas Find spodumene ore.

Dakota Minerals CEO David Frances commented: “This result further demonstrates the credentials of Lynas Find as a quality lithium deposit, with high grades from surface and high recoveries.” We are very pleased to have advanced Lynas Find from just an exploration target earlier this year, to a deposit we have growing confidence in ahead of the imminent release of our maiden resource, after which we look forward to exploring routes to maximise shareholder value from the deposit,” Mr Frances said.

Lynas Find Lithium Project: Diamond Drilling Programme Details

Two vertical diamond holes, 16DD01 and 16DD02, were drilled at Lynas Find Central in June 2016 (Figure 3). These were designed to twin RC holes 16LC012 and 16LC007 respectively. Pegmatite was intersected from 0.5 to 51.90m in 16DD01, and 16.77 to 44.00m in 16DD02. Spodumene mineralisation, visually estimated to be up to 60% of the core in some zones, was present in both pegmatite intercepts (Figure 1). The core was cut and sampled at SGS Metallurgy in Perth. Half-core was cut and sampled for metallurgical test-work, to determine optimal processing routes for the spodumene. Quarter-core was sampled and analysed for a multi-element suite by fusion/XRF, and for Li2O by fusion/ICP. The results of these are shown in Table 1 and Figure 2.

Lynas Find Lithium Project: Metallurgical Test Work Details

A master composite was formed using the half-core sampled from the two diamond holes at Lynas Find, which was then crushed to <35mm, blended and rotary split. 60kg of material was used to conduct a JK SMC test, Bond abrasion index test, Bond rod mill grindability at <12.5mm, and Bond rod mill grindability at <3.35mm. The remainder of the material was crushed to <3.35mm and rotary split. Two splits were used to determine head assay by fusion/XRF and fusion/ICP. A split was then deslimed and screened into two main fractions (-3.35mm +1mm, -1mm +0.045mm), and HLS was conducted on each fraction at 2.6, 2.7, 2.8, 2.9, 2.96 and 3.1 SG, with the remainder of the split material used for flotation test work, ongoing at the time of this release.

Comminution Testwork

Comminution testwork, including JK SMC, Bond abrasion index (AI), Bond rod mill grindability (BRWI) and Bond ball mill grindability (BBWI) was conducted on representative sub-samples of the coarsely crushed master composite. Comminution results are summarised in Table 2:

Beneficiation Testwork

The master composite sample was control crushed to <3.35mm, blended with a rotary sample divider and split into representative sub-samples for testwork. Duplicate splits were prepared using a tungsten carbide pulverising bowl and submitted for chemical analysis. Summarised head assay results are given in Table 3:

A representative sub-sample of the master composite was de-slimed by wet screening at 0.045mm. The wet screen oversize was dried and fractionated into two size ranges, -3.35mm + 1.00mm and -1.00 +0.045mm. The wet screen undersize was dried and combined with any further -0.045mm material generated by dry screening. A representative sub-sample from each of the three size fractions was prepared using a tungsten carbide pulverising bowl and submitted for chemical analysis. Summarised size fraction assay results are given in Table 4

Heavy liquid separation (HLS) was conducted over a range of densities on each of the fractions. The HLS results are shown in Table 5. For the 2.80 SG sink product, the -3.35mm +1mm fraction showed a recovery of 93.9%, producing a spodumene concentrate grading 6.55% Li2O. The -1mm +0.045mm fraction yielded an 81.8% recovery to produce a spodumene concentrate of 6.62% Li2O. This gives an overall weighted recovery of 90.6% from all fractions in the 2.80 SG sink product, producing a combined concentrate of 6.56% Li2O.

Summary

The HLS results indicate that a high grade Li2O concentrate (6.56% Li2O) was achieved, into a low mass (32.7%) concentrate stream, representing an overall combined recovery of 90.6%. The results indicate that dense media separation (DMS) would be a viable processing route for the Lynas Find spodumene ore.

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