The Fimiston Open Pit, colloquially known as the Super Pit, is an open-pit mine in Western Australia. It was Australia's largest open cut gold mine until late 2015, when it was overtaken by the Newmont Boddington gold mine, also in Western Australia. The Super Pit is located off the Goldfields Highway on the south-east edge of Kalgoorlie, Western Australia. The pit is oblong in plan view and is approximately 3.5 kilometres long, 1.6 kilometres wide and over 675 metres deep.
The Fimiston Open Pit is owned by Northern Star Resources. The mine produced of gold in 2019, and employs around 1,100 employees and contractors directly on site.
Earlier stages
The open pit area exists in what had been known as the 'Golden Mile' which consisted of a large number of historical mining leases and underground mines, including:
Paringa Oroya Brown Hill Chaffers Hainault
Consolidation into a single open pit mine was first attempted by Alan Bond, but he was unable to complete the task.
The Fimiston Open Pit was eventually created in 1989 by Kalgoorlie Consolidated Gold Mines, a 50:50 corporate joint venture between Homestake Gold of Australia and Gold Mines of Kalgoorlie (a Normandy Mining subsidiary).Treadgold, Tim. (1995) "History of the pit's development from 1989 to 1995", Australia's mining monthly, May 1995, pp. 31, 33-36. Barrick Gold acquired its share of the mine in December 2001, when it took over Homestake Mining Company. Newmont became part-owner of the mine three months later, when it acquired Normandy Mining in February 2002.MINEDEX website Golden Mile / KCGM search result, accessed: 26 January 2010 Saracen Mineral Holdings Limited acquired its share of the mine on 28 November 2019, when it purchased Barrick Gold's 50% stake.ASX Limited Northern Star Resources acquired its share of the mine on 3 January 2020, when it purchased Newmont's 50% stake.ASX Limited
Geology Most of the gold mined in the Fimiston Open Pit occurs within ore lodes formed by ancient shears in a rock unit called the Golden Mile Dolerite. The gold mining area of Kalgoorlie-Boulder-Fimiston has long been called the Golden Mile because of the geographical concentration of rich mines in that area, even though the lodes occur in an area over 2 km in length and 1 km in depth.
Production Mining is via conventional drill and blast mining via face shovels and dump trucks. Around 15 million tonnes of rock are moved in any given year, consisting primarily of waste rock.
Gold within the Golden Mile lode system is unusual in that it is present as telluride minerals within pyrite. In order to recover the gold, the ore must be crushed, passed through a gravity circuit to recover the free gold present in some of the higher-grade lodes, and then subjected to flotation to produce an auriferous pyrite-telluride concentrate. The concentrate is then treated at an IsaMill Ultra Fine Grinding (UFG) mill at Fimiston and then cyanidised, or trucked to the Gidji Processing Plant, 20 kilometres north of Kalgoorlie. At Gidji, the concentrate is treated in ultrafine grinding (UFG) mills, and then subjected to cyanide extraction of gold.
Prior to the installation of the UFG mills, concentrate was treated at Gidji in two circulating fluid bed roasters. Roasting ceased in 2015.
The operation requires significant amounts of power, and the mine ordered hybrid power plants in 2025 for 25 years, including a 132 kV grid, 120 MW thermal power, 256 MW wind power, 138 MW solar power, and a 138 MW / 300 MWh grid battery.
Figures Past production figures were:The Australian Mines Handbook - 2003-04 Edition page: 127 Year Production Grade Cost per ounce 1998-99Normandy Mining Ltd - 1999 Mine-by-Mine Operating Results accessed: 14 February 2010 718,554 ounces 2.37 g/t US$236 2000 715,164 ounces 2.27 g/t A$325 2001 616,344 ounces 2.14 g/t A$397 2002 720,050 ounces 1.73 g/t A$222 2003 2004 2005 2006 2007 628,000 ounces 1.53 g/t 2008 612,000 ounces 1.56 g/t 2009 690,000 ounces US$609 2010815,000 ounces 2011815,000 ounces 2012660,000 ounces 2013660,000 ounces 2014670,000 ounces 2015645,000 ounces 2016655,000 ounces 2017700,000 ounces 2018650,000 ounces 2019450,000 ounces 2019–20 2020–21 472,089 ounces A$1,385 2021–22 486,001 ounces 1.4 g/t A$1,426 2022–23 432,001 ounces 1.3 g/t A$1,596
References
Bibliography
External links
Super Pit (Kalgoorlie) Deposit Summary
MINEDEX website: Golden Mile / KCGM Database of the Department of Mines, Industry Regulation and Safety