AVZ Minerals
Sediments being exposed as water levels drop at Roche Dure

ASX-listed AVZ Minerals is making headway with its definitive feasibility study fieldwork programme at the Roche Dure pit within the greater Manono lithium project in the Democratic Republic of Congo.

Democratic Republic of Congo – The DFS field programme is gaining momentum with accelerated dewatering; engagement of geotechnical and hydrogeological consultants and studies now planned and commissioned.

The pit floor drilling programme at Roche Dure is also being considered and tendered to several local DRC-based drilling companies.

Tenders have also been received from three DRC based environmental consultancy groups for the environmental and social impact assessment study (ESIA) which will generate such items as the long term environmental management plan, the surface water management plan and the social development programme, that will be managed by the AVZ Foundation for the benefit of the Manono town residents.

Roche Dure dewatering programme

A five ton Allight Sykes CP300 high volume dewatering pump was commissioned at Roche Dure early in September 2019, with almost immediate results on reduction of the water level at Roche Dure. This pump has been combined with a pontoon based spindle pump, which can be maneuvered over deeper ‘holes’ in the pit floor to ensure that there are no flooded, pit floor depressions that will come to light as the water level drops further.  

“With both pumps combined we were able to draw down the greatest surface area at the top of the water filled pit by 0.75 m in 55 hours. As bathymetric work indicates the pit is a maximum of approximately 25 m deep, we anticipate the pit may be emptied quicker than the 3 months initially anticipated,” says AVZ Minerals MD Nigel Ferguson.

Planning has therefore been finalised to drill a sufficient number of tons of the pit floor to ‘bank’ the project. This is estimated at 25 Mt of inferred resource within the pit floor being brought to a measured resource category, says Ferguson.

Phase 2 Geotechnical programme

Johannesburg-based geotechnical company, Middindi Consulting, has been awarded the Phase 2 geotechnical contract to collect DFS level information to assist in the appraisal of wall angles required for the final mine design.

Field studies will require mapping of hanging-wall overburden, along with specialist mapping of pegmatitic outcrops, exposed near the current pit edges as well as in the soon to be exposed pit walls. Drilling of specialised orientated drillholes for statistical analyses of discontinuities and to collect samples for a suite of rock strength tests will be carried out in the last quarter of 2019.

Possible plant and tailings dam sites being investigated

In August 2019, Chris Lane of Land & Marine Geological Services, visited the site to appraise potential plant and tailings sites. He reported back to the company recently and the information received has been very encouraging in the initial reconnaissance of various sites for the possible location of a new processing plant and tailings facilities for a minimum of 20-year mine life.

Read more about the appointment of the DFS contractor here

This work will continue into the last quarter of calendar 2019 and is being driven by GRES Engineering as they strive to optimise the location of the new processing facilities under the guidance of AVZ Minerals.