Name of the Mine
Leonora Operations.
Location
The mine is located 235 km from Kalgoorlie in Western Australia.
Mine Owner/s
St Barbara.
Brief Description
The Leonora Operations includes the Gwalia processing plant and underground mine, as well as nearby development opportunities (Tower Hill and Harbour Lights complexes) that form part of the Leonora Province Plan.
The Gwalia mine is the cornerstone of St Barbara’s Leonora Operations. At more than 1 600 m below surface, it is the deepest underground trucking mine in Australia.
Brief History
Gwalia has been operating for more than a century. It was originally established in 1896 as the Sons of Gwalia mine.
Primary Metals/Minerals
Gold.
Secondary Metals/Minerals
None stated.
Geology/Mineralisation
Gold mineralisation occurs as several en echelon, moderately east-dipping foliation parallel lodes within strongly potassic altered mafic rocks and extends over a strike length of about 500 m and to a vertical depth of at least 2 300 m. Four primary lodes have been identified - Main Lode, South West Branch, South Gwalia Series and West Lode.
Reserves
Total proven and probable reserves as at June 30, 2021, were estimated at 15.58-million tonnes grading 4.9 g/t gold.
Resources
Total mineral resources as at June 30, 2021, were estimated at 51.86-million tonnes grading 4.1 g/t gold.
Mining Method
Underground, open stoping with paste fill.
Major Infrastructure/Equipment
The mine includes a conventional carbon-in-leach circuit and has a nominal capacity of 1.2-million tons a year of hard rock and up to 1.4-million tonnes a year when softer material is blended. Other surface infrastructure includes a gas-fired power station, a paste fill plant, and a refrigeration plant to cool the underground operations.
Prospects
St Barbara released the Leonora Province Plan in June 2021, adding an estimated 1.4-million ounces of gold and a further 600 000 oz of gold from Gwalia Deeps (before depletion) in August, to the existing five-million ounces of gold.
St Barbara said in its ‘Annual Report 2021’ that the three-stage strategy of expanding sustainable production at a lower cost profile to deliver superior returns to shareholders remains on track.
Resource development and extensional drilling has started, as has a combined prefeasibility study for St Barbara’s Tower Hill and Harbour Lights complexes. The additional resource inventory supports a mill expansion study, which is scheduled for the fourth quarter of the 2022 financial year.
Contact Details
St Barbara,
Tel +61 3 8660 1914
Website https://stbarbara.com.au
Sources
St Barbara. Ore reserves mineral resources statement as at June 30, 2020 (August 24, 2020).
St Barbara. Website https://stbarbara.com.au (accessed January 24, 2022).