Name of the Project
Rietfontein and Beta staged hard-rock gold mine development project.

Location
Mpumalanga, South Africa.

Client
Stonewall Mining, a subsidiary of Stonewall Resources.

Project Description
A scoping study on Stonewall’s combined Rietfontein and Beta projects, which form part of the company’s TGME gold project, has proved positive.

The Rietfontein project hosts mineral resources of 2.55-million tonnes grading 11 g/t gold, while Beta has mineral resources of 4.72-million tonnes grading 6.6 g/t gold.

The study has indicated that a combined Rietfontein and Beta development can produce up to 100 000 oz/y at a processing rate of 440 000 t/y.

The first part of the scoping study focused on an initial low-capital and operating cost development approach at the fully permitted Rietfontein mine, which has a potential production profile of up to 60 000 oz/y. Ore will be processed at the TGME processing facility.

The planned mining design at Beta comprises conventional breast mining, with hand-held air leg drilling. A scraper will be used to clean the face and transport ore to a centre gully. An ore pass will be built from the centre gully to the footwall, where ore will be loaded onto trucks and transported to surface.

Run-of-mine ore will be trucked 2.5 km to the TGME plant. The preliminary production schedule contemplates underground mining of 240 000 t/y over nine years. This is considered a base-case scenario, with further work on reducing the capital and improving recovery as part of the planned preliminary feasibility study (PFS), which is expected to enhance project economics.

The processing of the Rietfontein and Beta ore will be done at the existing TGME processing plant following refurbishment and upgrade. Material will be crushed, milled and floated to produce a high-grade concentrate. The concentrate will be partially oxidised through the introduction of oxygen in a high-shear mixing environment. 

The concentrates will be leached through a high-grade carbon-in-leach (CIL) plant for the recovery of gold. Flotation tails will be processed through a separate CIL plant for the recovery of gold.

Significant effort will be put into gravity gold recovery, particularly at Rietfontein, given past records indicating a 30% free gold recovery over simple corduroy cloth tables. It is expected that modern gravity gold recovery methods will significantly improve the free gold recovery. Carbon will be processed through an elution plant for the recovery of gold.

The combined projects will have a nine-year mine life and a processing rate of 440 000 t/y.

Jobs to Be Created
Not stated.

Net Present Value/Internal Rate of Return
The combined Rietfonetin and Beta staged development will have a pretax net present value, at a 10% discount rate, of $166-million, and an internal rate of return of 81%.

Value
$64.9-million.

The Rietfontein project has a capital cost of 31.9-million and the Beta project a capital cost of 33-million, which will be funded internally through cash flow from the Rietfontein mine.

Duration
Mine construction and plant refurbishment are expected to start in early 2018 (subject to available funding) to deliver first ore to the plant by the end of 2018.

Latest Developments
A drilling programme is planned for the Rietfontein project to increase the confidence level of resources in the mining inventory by increasing the quantity of indicated resources, as well as to test for strike and depth extensions.

In addition, samples will be taken from the current underground faces to upgrade the current resources at the Rietfontein mine. This resource sampling will generate samples for metallurgical testwork, which will allow for further enhancements to the process flow diagram and provide input into the geotechnical and groundwater studies.

Key Contracts and Suppliers
None stated.

On Budget and on Time?
Not stated.

Contact Details for Project Information
Stonewall Mining, tel +27 013 768 1271 or email admin@stonewallmining.com.