Name of the Project
Uis tin mine Phase 1 expansion project.

Location
Namibia.

Project Owner/s
Tin mining company AfriTin Mining.

Project Description
A definitive feasibility study (DFS) has confirmed the feasibility of expanding the current Phase 1 processing plant, resulting in a 67% increase in tin concentrate production from 720 t/y to 1 200 t/y.

The DFS proposes enhancements to the current processing plant, which will result in a modular expansion of the existing crushing circuit to increase ore throughput by 50%. It also proposes the upgrade of the existing concentrator circuit to accommodate the increased crushed ore feed tonnage and increase projected overall tin recovery target from the current 60% to 64%.

The detailed upgrades include:

• the addition of a crusher and screen between the primary jaw crusher and the fines crushing section;

• the addition of a buffer stockpile between the crushing and concentrating sections;

• the increase of the water rejection capacity in the dense-medium separation (DMS) 1 section;

• combining the dense-medium circuits of DMS 2 and DMS 3 to improve operability and stability;

• converting the DMS 2 floats recrush circuit into a closed circuit by adding a classification screen;

• additional spirals to reprocess middlings; and

• the relocation of product handling infrastructure and the installation of an additional shaking table for improved processing capacity. The existing shaking tables will be replaced with Holman tables for higher separation efficiency.

The DFS is based on a tin-only basis and currently excludes tantalum and lithium concentrate as potential by-products – these commodities are being investigated by AfriTin’s metallurgical testwork programme.

The Uis mine has proven and probable reserves of 15.61-million tonnes grading 0.14% tin for 21 536 t of contained metal.

Potential Job Creation
The project will be complemented by the appoint­ment of a skilled and experienced project management and construction management team to reduce implementation time and limit project implementation risks.

Net Present Value/Internal Rate of Return
The project has a net present value of $12.1-million and an internal rate of return of 54%, with a payback of 2.4 years.

Capital Expenditure
The project is estimated at $5.7-million.

Planned Start/End Date
The project is expected to take eight months to complete, including a two-week full plant shutdown. Production will, nonetheless, continue during the implementation period, minimising production interruptions.

Latest Developments
The Uis project has maintained a production level above its steady-state target during the second quarter of its 2022 financial year, surpassing the targeted 180 t of tin concentrate by producing 185 t containing 113 t of tin metal.

A strong operational performance during the quarter ended August 31, was supported by a 9.9% increase in processing plant throughput and a 10.2% improvement in tin recovery.

Implementation of the Uis Phase 1 expansion project started during the quarter and also contributed positively. It is expected to increase tin concentrate production by 67%.

Meanwhile, AfriTin Mining has said that it is excited about the opportunity to diversify and consolidate its techmetal exposure, after receiving positive preliminary results from lithium beneficiation testwork.

The company will soon launch an 8 000 m lithium and tantalum exploration drilling programme to increase the confidence levels of lithium and tantalum by-product potential at the Uis mine.

Lithium oxide at Uis occurs primarily as the mineral petalite in the ore, which is treated by the current processing facility. The company aims to produce a low-iron petalite concentrate containing a minimum of 4% lithium oxide and a maximum of 0.05% iron oxide.

It is expected that the process flow design of a petalite concentration circuit will involve a combination of density separation, flotation and magnetic separation methods.

The current phase of AfriTin’s lithium oxide testwork programme will investigate density separation methods to concentrate petalite. Bulk samples have been acquired from the active mining area and transported to testwork facilities in South Africa.

Heavy liquid separation (HLS) and pilot DMS testworks are being conducted concurrently.

Preliminary results from HLS tests indicate an upgrade factor for lithium oxide of four to five times, in line with the company’s projections for DMS preconcentration.

The HLS and DMS testwork will be followed by characterisation of concentrate samples, which will inform the second phase of testwork.

Tantalum at the Uis mine occurs primarily within columbite group minerals, which have a similar density to the tin-bearing mineral cassiterite and is recovered as part of the tin concentrate.

The company does not receive a credit for the contained tantalum within the tin concentrate; therefore, the aim is to separate the tantalum-bearing minerals from the tin concentrate and create a by-product.

While optimisation testwork on tantalum continues, the company will proceed with the process flow design for a pilot tantalum concentrate production facility at Uis, with implementation planned for the fourth quarter of this year.

In tandem to the metallurgical testwork and process development, AfriTin has started a larger exploration focus over its licence areas. The immediate priority is an infill exploration drilling programme over the V1/V2 orebody, aimed at increasing the geological confidence of the existing mineral resource estimate for tantalum and lithium oxide.

The programme also aims to improve the classification of these minerals from the inferred to indicated and measured categories for that portion of the orebody extending to a depth of about 150 m. This will provide increased confidence in mineral concentration and production estimation modelling, and might lead to the existing ore reserve estimate for tin being updated for tantalum and lithium oxide.

Key Contracts, Suppliers and Consultants
Minxcon (DFS).

Contact Details for Project Information
AfriTin Mining, tel +27 11 268 6555.