Name of the Project
Gwalia extension project.

Location
Western Australia.

Client
St Barbara.

Project Description
A detailed budget and execution plan on the Gwalia project have confirmed that the project will generate a robust financial return and extend gold mining at Gwalia to at least 2 000 m below surface in the 2024 financial year. It will also provide the foundation for potential further extensions.

The project comprises a ventilation upgrade and paste aggregate fill (PAF).

The project provides additional ventilation through raisebore intake and exhaust ventilation shafts, and related power and cooling infrastructure needed to mine between 1 800 m and 2 000 m below surface.

To manage the primary execution risk associated with long raisebore shafts, the design uses shorter, two-stage raisebore shafts, connected by horizontal development.

PAF involves mixing paste from the surface with waste rock crushed underground for stope fill. Disposing waste underground enables truck and ventilation resources to focus on ore production, boosting efficiency and potentially increasing production. PAF also allows for faster stope filling and, therefore, reduces stope cycle times.

Expediting PAF for use during ventilation shaft construction will allow for underground disposal of raisebore chippings, significantly reducing the impact of the project on ongoing production and greatly enhancing overall project value.

Jobs to Be Created
Not stated.

Net Present Value/Internal Rate of Return
Not stated.

Value
The project has a budget of A$100-million.

Duration
The project will take two-and-a-half to three years to complete.

The timeframe for completion of the raisebore shafts will depend on the eventual sequencing of the four individual shafts.

The PAF should be completed within 12 months.

Latest Developments
The St Barbara board has approved capital expenditure relating to the Gwalia extension project.

Should the current drilling programme identify sufficient resources below 2 000 m, the feasibility study defines additional infrastructure that could extend ventilation from 2 000 m below surface to allow for mining to 2 200 m below surface at a cost of A$30-million to A$35-million.

Key Contracts and Suppliers
None stated.

On Budget and on Time?
Not stated.

Contact Details for Project Information
St Barbara, tel +61 3 8660 1900, fax +61 3 8660 1999 or email info@stbarbara.com.au.