CSE-listed exploration and development stage miner Tantalex Lithium Resources reports that heavy liquid separation (HLS) metallurgical test work on a 331 kg composite bulk sample from the K-dump at its Manono reclamation project, in Congo-Brazzaville, reveals more than 6% lithium oxide spodumene concentrates.

These occur at high lithium recoveries exceeding 60% and have an iron content of about 1.3% iron oxide without conducting any magnetic separation on the concentrate produced.

Mineralogical analysis of the sample indicates that nearly all the lithium is contained in spodumene; while cassiterite is the only tin-bearing mineral, and in the case of tantalum the overwhelming majority occurs as tantalite with low concentrations of tapiolite.

Although HLS results are only an indication of a dense media separation (DMS) circuit’s performance in operation, Tantalex reports that the results indicate that DMS will be applicable to the project’s flowsheet as a primary driver for lithium recovery in the coarse fraction.

Additional conventional technologies will be tested to establish the best beneficiation method of the less-than-0.5-mm fraction.

COO Hannes Miller says the results from this initial test work are encouraging because of the fact that it is dump material. “The asset has very little mining cost associated with it and producing a marketable product with a robust well-known process is strongly preferred to a flotation-only operation.”

He adds that DMS is a less complicated process to operate, more cost effective, and may be commissioned over a significantly shorter timeframe.

The 331 kg composite bulk sample on which the tests were conducted is a sub-sample of a 2 t sample taken from drill holes MDC047, MDC056 and MDC 064 at the K-dump.

A primary reason for the strong HLS results is the coarse-grained nature of the spodumene at K-dump which enables for strong liberation of the spodumene with no crushing required as the in-situ material is 99% less than 5 mm.

As a result, Tantalex can process ore using the most conventional mineral processing technique in the industry without any additional crushing/grinding required. The cut density can also be lowered from 2.95 t/m³ that was used in the test work to improve recoveries while maintaining SC6 grade.

Further, the HLS testwork indicates that there is potential to opt for a phased approach in constructing the plant by firstly beneficiating the coarse fraction in a robust cost-effective way while expanding the process facility at a later stage to recover the fine valuable material.

The metallurgical test programme was completed by CoreMet Mineral Processing in South Africa and included head characterisation and HLS test work to develop appropriate beneficiation methods.

Going forward, Phase II test work will include a DMS, gravity, upstream classification, and flotation test run using the remaining bulk sample.