| Stawell Mine |
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Perseverance owns and operates the Stawell Gold Mine, located 2km from the Stawell township, which is approximately 250km west of Melbourne, Victoria. History Gold was discovered at Stawell in 1853, and production from alluvial sources and high-grade quartz reefs totalled an estimated 2.67 million ounces (including 0.77 million ounces alluvial) in the 73 years until the last historic mine closed in 1926. Mining re-commenced in 1982 when the Stawell Gold Mine was reopened and mining of the Wonga open pit commenced. In the subsequent nine years the mine produced 336,000 ounces of gold. Total historical production, together with the estimated ore reserve and mineral resource at December 2005, gives the gold deposits at Stawell a total endowment of over 5 million ounces of gold. The most recent Ore Reserve and Mineral Resource statement was released with the December 2005 Quarterly Production Report. An updated statement is expected to released with the 2007 Annual Report. A graph of Stawell Gold Mine’s mineral inventory is shown below.
Mineral resources are quoted exclusive of ore reserves. Mine Geology The Stawell Gold Mine occurs within a major northwest trending structural corridor along the western margin of the Lachlan Fold Belt. The gold orebodies at Stawell are associated with the Magdala Dome comprising a doubly plunging 1km wide unit of basalt enveloped by sulphide and iron enriched sedimentary rocks (termed “volcanogenics”) that host the majority of the ore-grade mineralisation. Ore formation was associated with hydrothermal fluid flow along major reverse faults mostly localised on the western flank of the Magdala Dome. Typically, gold is accompanied by sulphides in multiple ore horizons including Central Lode, Stockwork and Basalt Contact lodes. Mine Planning The mine plan is updated each year using recent operating, resource definition drilling and exploration data. The current mine plan is scoped to 1270m depth. Mining The mine is accessed by a 1:8 decline from a portal located adjacent to the mill. The mine access development and services are located mainly within basalt. Ground conditions are good and there is no history of seismic activity. Development follows the Magdala lode system down plunge, and between 470 RL and 786 RL the decline splits into a north and a south decline. To facilitate ore access, extraction levels are developed at 19m vertical intervals. The mining areas currently extend over approximately 3km of strike to more than 1,000m below surface, measured from the top of Big Hill. The mining method is bench stoping with cemented rock fill pillars in primary stopes, and rock filled secondary stopes. In narrow ore zones, drives are developed in ore. In the wider zones, footwall drives and draw points are sometimes used. In the Magdala orebody, stope sizes typically range from 2,000 to 10,000 tonnes. In Golden Gift where the width and tenor of the reserves have so far been of higher quality, generally larger stopes up to 15,000 tonnes are expected. Approximately 80% of stope ore is recovered using loaders under remote control, with haulage by 50 tonne trucks. The access decline is used as an intake airway, and a chilled water plant delivers conditioned air via an intake shaft. Exhaust air is drawn through the workings to a ventilation shaft at the northern end of the mine. The mine is relatively dry. Water pumped from the workings is recycled for use in the mine or the treatment process. Metallurgy Coarse gold (up to 30% of the gold in mill feed) is recovered from the milling circuit in self-cleaning centrifugal gravity concentrators. Tailings and Rehabilitation The Stawell mine operates on the basis of zero liquid discharge from site. All mine and process water and plant tailings are stored on-site. Land is progressively rehabilitated, and research into alternative uses for tailings is being conducted in conjunction with the University of Melbourne and Curtin University. Operations are managed in accordance with the Company’s Environmental Management System which is consistent with the Australian Minerals Industry Code for Environmental Management. Infrastructure and Services Power is provided to the mine from the state electrical distribution grid. Make-up process water and potable water are supplied by the regional water authority. A water harvesting program is maintained to augment process water and to minimise demand from the local authority. Tailings dam water is also recycled through the treatment plant. Employees At December 2006, there were 348 employees on site, including 139 contractors. |
ASX Annoucements |
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27/02/2008 - Public Announcement - MG Mining Contract(PDF 49kb) 27/02/2008 - Executive General Manager Northgate Australia Appointed(PDF 21kb) |
Quarterly Report |
14/01/2008 - Quarterly Report Dec 2008(PDF 1.04Mb) |
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| Community Newsletters |
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Community Newsletter February 2008 |
