Garden Well is an open cut gold mine located 100km north of Laverton in Western Australia. The mine is fully owned by Regis Resources.
Regis Resources commenced the earthworks and camp installation works at Garden Well in July 2011. The pre-production works began in September 2011.
Milling operations at Garden Well commenced in August 2012. Gold production began in September 2012. The mine produced 46,103oz of gold for the quarter ending June 2013.
Garden Well discovery, geology and mineralisation
Garden Well is an Archaean orogenic gold deposit located in the Duketon Greenstone belt, and is the largest gold discovery at the belt. The mine was first discovered in 2008. It is expected to have a mine life of nine years.
The deposit is covered by a tertiary palaeochannel consisting of gold anomalies. Gold mineralisation takes place in the east dipping gold-bearing zone of the clay rich residual Archaen saprolite. The mineralisation is a mixed ultramafic-sediment shear type.
The mineralisation is open along strike and at depth. It is present as oxide ore up to a depth of 70m beneath the base of paleochannel and extended as hypogene ore up to 400m.
Garden Well mine reserves
The Garden Well gold mine has reserves of approximately 1.66 million oz of gold. The combined measured and indicated JORC-compliant gold resources have been estimated at three million oz.
Gold mining and ore processing
Mining activities at Garden Well open cut mine commenced in September 2011. Mining was conducted using the truck and shovel excavation methods.
Rosemont is part of the Duketon Gold project, which also encompasses the Garden Well and Moolart Well gold mines.
The majority of mining at Garden Well was made in the supergene zone of the open-pit with minimal mining done in the structural zone.
A carbon-in-leach (CIL) gold processing plant was installed in August 2012. It has a capacity to process four million tonnes of ore per annum at a recovery rate of 95%. The ore from the Rosemont mine will also be processed at Garden Well processing plant for leaching and gold production. Rosemont mine is located just 9km north-west of Garden Well mine.
The processing plant at Garden Well gold mine includes a three-stage crushing circuit, scrubber, and an Outotec ball mill. The processed ore is treated by the gravity and carbon-in-leach circuits.
Infrastructure facilities at Garden Well gold mine
A single-celled paddock style tailings storage facility (TSF) was arranged adjacent to the processing site.
A 12MW power station located at the mine site provides the power required for mining and processing operations. The capacity of the power station is planned to be increased to 16MW for supplying power to the Rosemont gold mine.
Workers are accommodated at the 250-person accommodation village. The construction of the processing plant and accommodation village required an investment of $102m.
Regis Resources used the internal cash balances of Moolart Well gold mine for financing the Garden Well gold project.
The company also received $72m funding from Macquarie Bank for the development of Garden Well.
Contractors involved with the Garden Well development
Mining and Civil Australia (MACA) was awarded the contract for performing mining services at Garden Well. The scope of services includes drilling and blasting, loading, and hauling. The eight-year contract is valued at $450m.
Kalgoorlie Power Systems, a subsidiary of Pacific Energy, was awarded the contract to build the 12MW power station at Garden Well. Kalgoorlie has enabled power supply to the mine under the six-year contract.
Mintrex acted as the design engineer for the Garden Well gold mine. It was also responsible for conducting the feasibility study of the CIL processing plant.
EGRM Consulting conducted the mineral resource estimation for Garden Well gold mine.
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