lithium
Feature image credit: Wikimedia

ASX-listed lithium hopeful AVZ Minerals is blazing the trail for future lithium development in the DRC, with its first mover advantage in the highly-prospective Manono region in the south of the country.

This region was previously unexplored for this prized battery ingredient.

The company’s Manono project, said to be potentially one of the largest lithium-rich lithium, tin, caesium, tantalum pegmatite deposits in the world, has garnered attention in recent months with a series of wide, high grade lithium intercepts says MD Nigel Ferguson.

This article first appeared in Mining Review Africa Issue 8 2018

AVZ Minerals has had quite a dramatic rise to fame following its acquisition of the Manono lithium project in December 2016, which coincided with the global boom in demand for lithium, driven mainly by the opening up of a new market – its use in the manufacture of the batteries needed to store energy for the burgeoning electric vehicle sector.

AUTHOR: Mining Review Africa's senior deputy editor, Chantelle Kotze

In the short period from acquisition till now, AVZ Minerals has completed a review of historical data, geological mapping and a short seven hole drilling programme as part of the due diligence programme.

The company has also completed 75% of its initial 20 000 m drilling programme being led by DRC-based drilling contractor Equity Drilling and has undertaken initial characterisation and preliminary metallurgical test work.

More recently, the company has proved up a JORC-compliant total measured, indicated and inferred resource of 259.9 Mt grading 1.63% Li2O (spodumene) containing 4.25 Mt of lithium oxide (Li2O), 219Kt of tin as cassiterite grading 844 ppm Sn and 11.2Kt of Tantalum grading 43 ppm Ta2O5 tantalum (estimated on an approximate 50% of the Roche Dure pegmatite) at the beginning of August, and is underway with a scoping study, which is being led by Perth-based independent engineering group CPC Engineering.

Manono makes a name for itself

The Manono project, which is located about 500 km north of Lubumbashi, comprises one main exploration permit covering 242.25 km2, surrounding the world-class historic Manono tin mine.

The Manono pegmatite deposit, which has a strike length of at least 13 km, was historically mined for its tin content between 1919 and 1980.

Having initially considered the Manono project about five years ago as a potential tin play, it was only in November 2016 that AVZ Minerals considered the project as a potential lithium source.

It was then that it acquired the project with a view to exploit the NE and SW strike extensions of the historic pegmatite for its lithium content – where AVZ Minerals had already confirmed two large areas containing pegmatites based on available historical data – the two largest pegmatites in the two areas being Carriere de L’Est in the NE (Manono sector) and Roche Dure in the SW (Kitotolo sector).

Moreover, the company also holds a 60% stake in seven exploration licences covering a total of approximately 1 172 km2 within the immediate region surrounding the historic Manono tin mine.

These licences were of interest to AVZ Minerals because they are known to host lithium bearing pegmatites which are prospective for both lithium and rare earth elements.

Ferguson, a geologist with over 30 years of experience, has led the exploration activities at Manono to date, with the help of former executive chairman and leading DRC geologist and explorer Klaus Eckhof, who has since resigned from his role to pursue other exploration opportunities in the DRC.

In January 2017, AVZ Minerals commenced mapping and trench and channel sampling which was followed by an initial drill programme during March and June 2017, to evaluate the potential of the Manono and Kitotolo pegmatites to contain economically significant lithium mineralisation.

During this programme six drill holes were completed in the Kitotolo sector and one in the Manono sector.

This is currently being followed up by an initial 20 000 m phase of a proposed 40 000 m drill programme which started in February 2018 to test, define and report initial mineral resources at the Kitotolo and Manono sectors of the Manono lithium project.

“Five drill rigs are currently working on site, and have drilled about 16 000 m by July, says Ferguson, who anticipates the completion of about 26 000 to 27 000 m of drilling by the end of the initial drill programme in September.

In June, AVZ Minerals began its scoping study for the Manono lithium project to prepare initial capital and operating cost estimates based on a typical hard rock spodumene concentrate process flowsheet with a 2 Mtpa, 4 Mtpa and 10 Mtpa processing scenario.

As part of the study a high-level review of options to upgrade the spodumene concentrate will be undertaken, with the aim to minimise transportation costs, while a second high-level review will investigate opportunities to produce a cassiterite concentrate as a secondary product stream to offset mining and transport costs.

The estimate will capture the process plant, process and non-process infrastructure.

Having reviewed the preliminary characterisation test-work results, AVZ Minerals is modelling a process plant with the following processing stages:

  • Three stage crushing circuit;
  • Screening circuit;
  • Reflux classification for mica removal;
  • Dense media separation;
  • Desliming;
  • Grinding and flotation; and
  • Concentrate handling.

The scoping study estimate will also model water supply, power generation, process plant offices, workshop, and associated infrastructure, within the process plant, accommodation camp, communication systems and sewage/waste disposal.

In terms of metallurgical test work, AVZ Minerals has undertaken characterisation test work on two samples of coarse assay sample reject material from two drill from the Roche Dure pegmatite, where most of the drilling has been concentrated.

Ferguson says the metallurgical test results were encouraging with several potential processing routes available to produce a spodumene concentrate product of +6% lithium at recoveries of 73% using dense media separation (DMS) to 94% using flotation.

The preliminary test work also indicated that a +6% spodumene concentrate could be produced at 3.35 mm crush size, with a high overall recovery using standard flotation or several variations of a combined DMS and flotation process, he notes.

Having released a maiden resource estimate for Manono AVZ Minerals is on track for the completion of its scoping study and drilling programme in August and September respectively and will thereafter commence geotechnical and metallurgical drilling and undertake further work on infrastructure and routes for delivery of product by year end, in a bid to bring the Manono project to feasibility study stage by late 2018 for completion by mid-2019.

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