AVZ Minerals Limited (ASX: AVZ) has announced the identification of an initial exploration target for alluvial placer hosted tin at the Manono Lithium and Tin Project in the Democratic Republic of Congo.
AVZ said that the possible scale of the Exploration Target in the Likushi Flats falls between 25 million and 75 million cubic metres, with a diluted grade range of 75 to 180 grams per cubic metre.
Exploration at Manono
Between 1939 and 1943, Zaïretain (operators of the Manono Operation) had completed detailed exploration evaluating the alluvial and laterite hosted cassiterite potential of areas proximal to Manono and along the Likushi River alluvial plain.
Manono was a consistent producer of cassiterite for over 60 years, producing over 180,000t cassiterite being primarily sourced from eluvial, lateritic, and hard rock pegmatite sources. This is worth over US$5.4 billion at today’s tin price.
The work completed by Zaïretain comprised in house as well as independent studies that resulted in the definition of several alluvial and laterite cassiterite blocks/mineral inventories. However, to date, no modern or systematic exploration or evaluation was completed to test or validate the inventories.
Review by Behre Dolbear
The company had assigned independent geological and mining consultants, Behre Dolbear International Limited (Behre Dolbear), based in the United Kingdom for conducting an independent review of historical exploration records produced by Zaïretain.
There has been a significant recent rise in global tin prices to over US$30,000 per tonne representing an increase in price of >50% from the start of 2021. The company said that this supports its plans to evaluate the possibility of developing and adding value from the alluvial tin potential at Manono.
Initial exploration target defined
Behre Dolbear has now defined an Exploration Target over the Likushi Alluvial Plain area of 25Mm3 – 75Mm3 grading (diluted) 75g/m3 – 180g/m3 cassiterite concentrate. The Exploration Target covers an area of ~14km2 and has been defined by five separate inventory blocks (F1, F2, F3, F4, and F5) each being classified according to proximity to the existing mining operations as well as confidence in the distribution and tenor of cassiterite mineralisation.
The company noted that this exploration target is in addition to the existing JORC 2012 compliant hard rock tin and tantalum Mineral Resource Estimates (MRE) of 125 million tonnes @ 175ppm Sn and 26ppm Ta (low grade tin domain) and 275 million tonnes @ 962ppm Sn and 38ppm Ta (high grade tin domain) at a 0.5% Li2O cut off published in the 21st April 2020 DFS study.
Potential for standalone operation
The company said that the initial exploration target defined at the Manono demonstrates the significant potential for a possible standalone alluvial tin mining operation at Manono.
AVZ noted that all prospects remain open and under-explored with considerable potential for discovering additional deeper tin bearing palaeochannels.
AVZ reported that additional laterite hosted tin deposits were identified for further work. The company said that it recognises the potential to convert some, or all of, the Exploration Target into a JORC 2012 compliant Mineral Resource Estimate with a combination of geophysical investigations, validation drilling, and bulk sampling to commence during the dry season.
The company noted that to confirm the volumes and grades defined in the Exploration Target, a validation drilling, sampling, metallurgical test work, and ground geophysical (ERT or similar) programme will need to be undertaken. The positive outcome of this exercise will enable (part of) the Exploration Target area/s to be converted into a Mineral Resource Estimate, compliant with the JORC Code. This would then enable Dathcom to proceed immediately with a Preliminary Economic Assessment (PEA) or Scoping Study.
“There is compelling evidence to suggest that significant alluvial tin placer resources exist in the floodplains along the banks of the current and palaeodrainages of the Likushi River”
AVZ’s Managing Director Nigel Ferguson, said: “We have been aware that historical exploration work had been conducted on the extensive alluvial tin resources to the north of the main hard rock pegmatite orebodies in the latter years of the historical mine’s operation by the previous mine operator, Zaïretain. The obvious first step in determining the success or otherwise of this work was to conduct a full review of all available information. Subsequently, we contracted Behre Dolbear in the UK to carry out this study due to their previous geological investigations in this area and I am pleased to present their results here.”
There is compelling evidence to suggest that significant alluvial tin placer resources exist in the floodplains along the banks of the current and palaeodrainages of the Likushi River. With a strengthening tin price this could represent a significant geological resource worth pursuing.
Zaïretain also exploited and evaluated the potential of laterite hosted eluvial tin deposits in the Kitotolo Sector. Presently, there is insufficient confidence in the data to determine an Exploration Target, but research investigation has provided sufficient information to guide future exploration programs targeting these styles of mineralisation.”
Image Source: AVZ Minerals Limited