Letlhakane Uranium Project

Project Summary

The Letlhakane Uranium Project is one of the world’s largest (global top 10) undeveloped Uranium Deposits. The Project lies adjacent to Botswana’s main North-South infrastructure corridor that includes a sealed all-weather highway (the A1 Highway), railway line and the national power grid, all of which make significant contributions to keeping the capital cost of future developments low.

Project Overview

The Letlhakane Uranium Project, located in Botswana, is one of the world’s largest undeveloped Uranium Deposits. A Mining Licence designated ML 2016/16L was granted on 12 September 2016 and is valid for 22 years. The Department of Environmental Affairs formally approved the Letlhakane Uranium Project’s Environmental Impact Statement on 13 May 2016. Provisional surface rights were granted on 6 June 2016.

The Company’s Letlhakane Uranium Project remains an important project asset within the diversified minerals strategy. While the nuclear industry is confident in the long-term fundamentals of uranium and nuclear power, there is less certainty in the short term with industry expectation that the market will gradually move towards balance from calendar year 2025.

On 20 August 2019, the Company received confirmation by letter from the Botswana Minister of Mineral Resources, Green Technology and Energy Security, that the amendment was approved.

A-Cap is keeping its Letlhakane Uranium Project on a low-cost strategy with a small team in Botswana to keep the licence in good stead and keep communicating the project to the local communities. There has been some upward movement in the uranium price this financial year which is a positive sign of a forecast supply constraints in the coming years.

Increased investment sentiment and an increased uranium price has bought forward technical planning of further works. Planning for Drilling and metallurgical testwork that were suspended back in 2018 are underway to further the positive project value-adding results that sort to reduce capes and opex through understanding of the processing acid consumption of different mineralised lenses.

Mining License

A mining Licence application for PL 45/2004 (Letlhakane) was submitted to the Botswana Department of Mines, based on the results of a technical study and financial modelling. The technical study was based on shallow open pit mining and heap leach processing to produce up to 3.75 million pounds of uranium per annum over a mine life of 18 years. The study incorporated the most up to date metallurgical results and process route, optimised mineral resources, mining, capital and operating costs developed by our feasibility specialists in Australia and internationally. The technical study confirms that the Project has the right mix of a good resource, low capital and operating costs and is well positioned to be taken into early production in line with forecast rising uranium prices.

The technical study and financial modelling were completed with the assistance and in collaboration with, a world-class team of consultants including Optiro, Cube Consulting, SLR Consulting (South Africa), Kappes Cassiday & Associates, OMC Hydromet and Lycopodium Minerals Pty Ltd.

On the 8thSeptember 2016, A-Cap received formal confirmation from the Botswana Department of Mines that the Company’s application for a mining licence for the Letlhakane Uranium Project (PL045/2004) was successfully approved. The mining licence was signed by the Minister of Minerals, Energy and Water Resources (MMEWR), his Honourable Onkokame Kitso Mokaila (MP) and takes effect from 12 September 2016, valid for 22 years.

Pursuant to Section 43 of the Botswana Mines and Minerals Act, 1999, “the holder of a mining licence may, from time to time, notify the Minister of amendments he wishes to make to his programme of mining operations and such amendments shall, unless the Minister rejects them within three months after being so notified, have effect after such period”. The Company have engaged in ongoing discussions with the Botswana Department of Mines apprising them of the delayed recovery in the price of uranium, coupled with staged project optimisation work currently being undertaken by the Company aimed at improving recovered uranium grade and reduce U3O8process costs, focussing on acid supply and consumption. These factors would therefore affect the target timelines as set out in the Company’s mining licence application.

A letter was submitted to the DoM on 10 July 2017 to advise that the pre-construction and construction period would be delayed by two years. The Company received correspondence from The Botswana Minister of Mineral Resources, Green Technology and Energy Security on 20 September 2017 formally advising the Company that the amendment to the programme of works for Mining Licence 2016/16L was approved.

The Botswana Minister of Mineral Resources, Green Technology and Energy Security, has extended the start of construction to 30th September 2024, amending a condition of the granted Mining Licence.

A-Cap complies with all the requirements of the mining licence to ensure continued good standing, including defining the boundary of the mining licence with beacons, clearing and demarcation, and report submission in a timely manner.

Project Optimisation

Increased investment sentiment and an increased uranium price has bought forward technical planning of further works. Planning for Drilling and metallurgical testwork that were suspended back in 2018 are underway to further the positive project value-adding results that sort to reduce capes and opex through understanding of the processing acid consumption of different mineralised lenses.

During the 2017-year, A-Cap sent 296 samples for acid soluble uranium (ASU) analysis to ANSTO laboratories at Lucas Heights, NSW. The test design was aimed at addressing possible correlations with acid consumption and hence samples were carefully selected to represent lithological, spatial and mineralogical parameters. The samples utilised were all sample pulps from XRF analysis from previous drill programmes.

The ASU test was developed as a proxy for acid consumption and uranium recovery in a heap leach as it is logistically easier to deploy and has a much shorter lead-time in comparison with conventional column tests that can take up to 100 days to complete. The test uses conditions similar to a heap leach process in terms of acid concentrations and catalysts. In addition to the leach time, the other notable difference between the ASU and the heap leach process is the material size, which is required to be pulverised for the ASU. The ASU testing will give relative differences between samples, however the overall consumption for the heap leach can only be treated as indicative.

The results of the analysis indicated acid consumption correlations which have potential in reducing the overall acid consumption for the project. The potential lies in being able to differentiate high and low acid consuming mineralisation prior to processing it. The results from the ASU analysis showed spatial, lithological and mineralogical relationships with higher acid consumption.

The main observations were:

  • Spatially – where at Serule the basal lenses have higher acid consumptions than the upper lenses; and by prospect where the range of acid consumptions is greater at Serule West than at Kraken or Gorgon.
  • By lithology type;some mineralised lithologies have higher averages of acid consumption relative to others.
  • By geochemistry; The samples when arranged by ‘like’ geochemical signatures or clusters. Some clusters correlate with higher acid consumption.

The geochemical clusters identified by the head assay geochemistry were often prevalent across different lithologies, indicating a mineralogical overprint that is a factor for acid consumption. When taking the observations with the selective mining approach, avoiding higher acid consuming areas has the potential to decrease the overall acid consumption, which is a key cost driver in the Project’s operating costs.

As the results are only relative, further leach testing will be required simulating process conditions of the heap leach. In August 2017 A-Cap sent an additional 100 samples for ASU test work in August 2017 to expand the sample population of the study.

Predicted and actual resulting acid consumptions were spread spatially in the geological resource model using both krigging and inverse distance estimation methods. The results showed spatial differences with higher acid consumption. Three of the prospects were covered by the analysis: Gorgon South, Kraken and Serule West. At Serule West, around the pit areas, the two basal mineralised lenses indicate an average almost twice the acid consumption of the upper lens. Both Kraken and Gorgon South exhibited an average increase of acid consumption with depth. This relative difference in acid consumption from the pulps could change the optimisation parameters, as the higher lens may become more economic relative to the basal units. Figure 3 graphically show the increased acid consumption when Sodium (Na) is elevated. A minor relationship can be seen with an increase in carbonates. Figure 4 illustrates an increase in acid consumption with depth of the mineralised lens and an increase of Na with deeper lenses.

Figure 3 Trends for increasing acid consumption with increased Na and carbonate. Symbol size increases with Na

Figure 4 Mineralised lenses numbered with increasing depth illustrates samples with higher acid consumption and Na

The samples were also arranged by similar geochemical signatures or clusters, with some clusters correlating with higher acid consumption. The geochemical clusters were identified initially by the head assay geochemistry, further refined by PLS cluster analysis. The cluster definitions were then used against an XRF sample database to predict the acid consumption based on the type of geochemical signature.

Sample results were also received from SGS laboratories (South Africa). 834 samples were sent for multi-element XRF analysis during the year and were used in the quantification of acid consumption within the prospect. The predictive model grouped the geochemical signatures from the results and attribute a predicted acid consumption based on the learning from the ASU samples. Data analytic software RapidMiner was used to run predictive models set up using the ASU head assay data with random sample sets used to measure percentage accuracy. Future XRF analysis either in-pit or pre-mining will have the ability to resolve acid consumers with even greater accuracy.

Mineralogy using QEMscan was completed on samples which represent the cluster types with high acid consuming properties. QEMscan is a technique that will define the mineralogical assemblage. The final QEMscan report received in January 2018 indicated that zeolites in Serule West were responsible for extreme acid consumptions that were observed.  The identification of the specific minerals associated with high acid consumption and the lithological and spatial mineralogical alterations will allow an assessment of the economic considerations associated with reducing the Project’s overall acid consumption. This could be achieved by eliminating the higher acid consumers from the mining process.

The new acid consumptions were entered into the OPEX model to create a new process cost per mineralogical cluster. These process costs have then been taken to an optimisation, so the economic outcomes can be viewed from a spatial perspective. As the acid consumptions are only predictive and relative, they will require testing by mineralogical cluster in a metallurgical column setting prior to official reporting of actual consumptions. Assuming the column results reflect the same relative acid consumptions as the ASU tests, the result could see overall acid consumption for the Project down by more than 20%.

The identification of the specific minerals associated with high acid consumption and the lithological and spatial mineralogical alterations allowed an assessment of the economic considerations associated with reducing the Project’s overall acid consumption. The mineralogy and spatial work has focussed the next phase of proposed optimisation work programmes to further mitigate high acid consumption or reduce the acid consumers at the point of mining. Beneficiation with respect to reducing acid consumers is being evaluated.

Metallurgy & Process Design

The Process Design is based on a 2-stage acid heap leach route for all the primary, oxide and secondary mudstone ores with a modified solvent extraction system being the principal uranium recovery method. A detailed programme of acid column leaching, Solvent Extraction (SX) and Ion Exchange (IX) testwork was completed in 2016 to better define recoveries and process operating costs for the Letlhakane heap leach operation. This was carried out at ANSTO in Sydney and SGS in Perth. In addition, SLR Consulting of South Africa, carried out a detailed engineering study of the heap leap facility including stability tests of the heaps.

At ANSTO, two campaigns of 2m and 4m columns were completed on the main ore types: Gorgon and Kraken primary ore, Serule West primary ore and a mixed oxide ore using the 2-stage acid leaching process which was developed over the last 2 years. This 2-stage acid leach has been shown to improve leach kinetics and recoveries. The 4m columns were leached in closed circuit with the SX/IX recovery circuit to demonstrate that the leachate can be processed by SX followed by IX then refining to yield a high purity saleable uranium oxide concentrate product. The SX/IX combination is novel though each component uses conventional technology and was demonstrated in the ANSTO Campaign 2 program. It was developed to optimise the water and acid balance and minimise acid loss in SX stripping.
At SGS, a 4m acid leach column test of the mixed secondary mudstone ore indicated good recoveries with moderate acid consumption indicating this process was the most effective way of treating this secondary mineralisation.

This testwork was used to develop engineering design data and process plant designs for acid heap leaching of all ore types excluding the calcrete ore. This data was used to define capital and operating costs for the process plant. The calcrete ore, which only accounts for <2 million lbs U3O8 resource, will be stockpiled for future processing once the main acid heap leach facility is complete.

The process flow diagram is summarised in Figure 5. The surface miners will produce primary, oxide and secondary mudstone ore feed for the closed screening and secondary crushing circuit which will produce a <19mm product feeding the agglomeration drums. The ore will be agglomerated using acid and polymer and then stacked by a grasshopper conveying system using 6 metre lifts. Leaching will be carried out in multiple stages using intermediate and raffinate solutions to limit the volume of PLS feeding the SX plant. Uranium will be recovered from the SX strip solution using continuous ion exchange, followed by purification and precipitation as sodium diuranate using hydrogen peroxide, before final precipitation of uranium oxide concentrate (UOC) and drying.
The process design and uranium recovery has some novel and innovative steps which are protected by two patent applications issued to A-Cap. These patent applications will protect some of the advances that the metallurgical study team have made in the uranium recovery process.

The technical study focussed on treating 9 million tonnes of mineralisation per year through crushing, agglomerating, stacking and sulphuric acid leaching on one of two permanent leach pads, each with a capacity of 79 million tonnes. Leached material will be left in place and each lift sealed with a geomembrane liner.

The design capacity of the processing plant is 3.75 million pounds per annum of U3O8 equivalent per year, to allow for peaks in production, with average annual production estimated at 2.4 million pounds. The acid leach project is expected to operate for 18 years based on the current in- pit resources of oxide, primary and secondary mineralisation. Uranium recoveries vary from 60.5% to 77.7% depending on mineralisation type and were derived by applying discounts for scale-up from laboratory conditions to commercial field operations and include recovery losses in the leach and recovery circuits. Comminution tests indicate that these materials are soft and not very abrasive with the average crushing work index (CWi) of 8.82 kWh/t (range 5.9-13.3kWh/t). Process costs were calculated by mineralisation type and pit. The major contributor to production is the primary mineralisation. The main operating consumable is acid.

Mineral Resource

A JORC Mineral Resource Upgrade at Letlhakane was completed by Optiro Pty Ltd, an independent expert, in September 2015. The updated resource uses a recoverable resource methodology which takes into account the proposed Standard Mining Unit (SMU). The SMU is defined by the proposed mining method utilising surface miners and the proposed grade control system using in-pit surface gamma radiation measurements.

The Localised Uniform Conditioning (LUC) estimate best reflects the mining methodology envisaged, taking into account the surface miners selective mining capability combined with the proposed grade control methodology. The accurate mining characteristics of surface miners and the ability to measure the gamma radiation on the surface during mining will ensure the optimum grade delivery to the process heap. The SMU of 20m x 4m x 0.25m forms the basis for the LUC estimation. Historic resource estimations were more reflective of conventional open pit mining and therefore had averaged resource data into blocks of bigger mining panels which smoothed or averaged the grade data.

Uniform conditioning (UC) and LUC are used for assessing recoverable resources inside a mining panel when the drill spacing does not provide sufficient coverage for direct grade estimation at the SMU scale. UC provides the proportion of SMUs inside a panel that are above cut-off and its corresponding average grade. LUC takes the UC result and spatially corrects the blocks making it more suited to extraction and optimisation studies.

The updated Global Mineral Resource, completed by an independent expert and reported in compliance with the JORC 2012 code, is summarised below:

Cut-off (U3O8ppm) Total Indicated Total Inferred Global Total
Mt U3O8(ppm) Contained U3O8 (Mlbs) Mt U3O8(ppm) Contained U3O8 (Mlbs) Mt U3O8(ppm) Contained U3O8(Mlbs)
100 197.1 197 85.5 625 203 280.1 822.1 202 365.7
200 59.2 323 42.2 209.7 321 148.2 268.9 321 190.4
300 22.2 463 22.7 81.6 446 80.3 103.8 450 103.1

Table 1: 2015 LUC Mineral resource estimates for ALL DEPOSITS at various U3O8cut-offs

The 2015 global resource estimate using LUC best reflects the mining methodology envisaged, taking into account the surface miners’ selective mining capability, combined with the proposed grade control methodology.

A drill spacing study comparison completed by Perth-based resource specialists Optiro on the Kraken deposit confirmed that at a starting drill spacing of 200m by 200m, the change of contained metal is within +/-10% when drilled down to 100m by 50m drill spacing. The current criteria for inferred resources is nominally greater than 100m by 100m drill spacing.  A-Cap has confidence that the deposit will retain its mineralisation continuity when it is further drilled out.

A-Cap continues to assess the LUC resource in terms of mining optimisations. Optimisations of the LUC resource model has been completed to assess the different mining techniques and also to determine the optimal areas for conversion from inferred to indicated resources. The mine scheduling and optimisation work going forward will be undertaken internally, which will allow for considerable savings in external resource modelling and optimisation costs going forward. Furthermore, in-house optimisation and scheduling capabilities will allow the complex nature of the Project to be examined in more detail and continuously.

Environmental Impact Statement

The Environmental Impact Statement (EIS, previously referred to as Environmental and Social Impact Assessment (ESIA)) for the Letlhakane Uranium Project has been approved by the Botswana Department of Environment Affairs (DEA) in accordance with Section 12 (1a) of the Botswana Environmental Assessment Act, No.10, of 2011. This is a major milestone for A-Cap and its flagship Uranium Project, with the EIS approval being an important requirement in securing a mining licence.

A-Cap first commenced work on the environmental study in January 2009, finalising and submitting the report in April 2015. The study identified the overall environmental and social impacts associated with developing a uranium mine in Botswana. The EIS process and documentation was prepared by independent experts SLR Consulting (Africa) (Pty) Ltd (SLR), in conjunction with Botswana-based consulting firm Ecosurv (Pty) Ltd. SLR and Ecosurv completed a professional study process comprising of a screening phase, scoping phase and a detailed impact assessment / environmental management phase, conforming with best practice and IFC guidelines.

The DEA formally approved the EIS on 13 May 2016 following a four-week public review process pursuant to the Environmental Act 2011.

Surface Rights

Provisional surface rights were granted on 6 June 2016 over the 144sqkm area covering the Letlhakane Uranium Project. The surface rights are provisional upon compensation for the affected land rights holders in the area being resolved. To date, multiple consultations with the communities and directly affected parties have been completed. An asset inventory census was completed in June 2017 covering the ML area to ascertain the number of properties and infrastructure within the area. The survey was well advertised in local newspapers and in the community notice boards to ensure that all affected parties could be contacted. In July 2017, the Tonota Sub Land Board commenced an asset evaluation within the ML area. Reports were finalised on the assets within the mining licence and were reviewed by the Lands Office, Francistown. The outcome from the Lands Office will pave the way for further consultative meetings with potentially affected parties.

Environmental consultants Ecosurv, based in Gaborone, have been engaged to undertake the Resettlement action plan (RAP) as outlined in the approved EIS.

Project Team

Under the guidance of Operations Manager Ashley Jones, the Project team continue to progress with project optimisation work for the Letlhakane Uranium Project, whilst evaluating potential nickel-cobalt laterite project opportunities and ensuring the Company continues to meet its mining licence and prospecting licence obligations. The Company continues to engage world class specialist consultants in the fields of geology, mineralogy, mining, metallurgy, process design, hydrology, environmental, radiation and engineering.


Sentiment about uranium continues to improve with the disruption to energy markets caused by the Russian invasion of Ukraine leading towards a sustained growth in demand. Prices for the “yellow cake” have settled at around $50/lb in 2022 after reaching the price of around $60/lb earlier in the year.

Rising support for nuclear energy and tight supply could possibly send uranium spot prices up to US$70/lb by 2023, according to Bank of America (BoA).


A-Cap remains committed to developing the Letlhakane Uranium Project, with the support of key stakeholders, as the first uranium mine in Botswana – a safe and stable multi-party democracy with an easy to understand mineral law. A-Cap continues to maintain an excellent relationship with all Botswana stakeholders through regular meetings and engagements, including all ministerial departments and communities. Botswana remains one of the best African destinations to invest, supported by:

  • Botswana ranks first in Africa for political stability.
  • Stable, multi-party democracy since 1966.
  • Skilled mining work force.
  • Highest GDP per capita in Africa.
  • Mining accounts for 40% of current GDP and is critical for continued economic growth.