The Super Pit, Kalgoorlie

A single pit swallowing the old Golden Mile mines

The Fimiston Open Pit, better known as the Super Pit, sits on the southeast edge of Kalgoorlie-Boulder, about 600 kilometres east of Perth. It is oblong, roughly 3.5 kilometres long, 1.6 wide and more than 675 metres deep, and it was Australia's largest open-cut gold mine until the Boddington mine overtook it in late 2015.

It is cut into the Golden Mile, one of the richest gold deposits in the world, found in the rush of 1893, when Will Brookman and Sam Pearce pegged the first leases, the Great Boulder and the Ivanhoe among them. By 1903 there were 49 mines working here, 100 headframes and more than 3,000 kilometres of underground workings. The gold lies in more than 1,000 separate lodes, faults formed by ancient shears in a rock called the Golden Mile Dolerite, some of them up to 1,800 metres long and 1,200 deep, in rocks between 2.6 and 2.9 billion years old. Much of it is locked up as tellurides inside pyrite, so the ore has to be crushed, floated, finely ground and treated with cyanide to give it up.

In the 1980s the West Australian businessman Alan Bond began buying up the separate leases, among them Paringa, Oroya, Brown Hill, Chaffers and Hainault, to bring them under one company, and failed to finish. In 1989 the whole area was combined under Kalgoorlie Consolidated Gold Mines, a joint venture of Normandy and Homestake. The smaller pits were merged into one, and every underground mine except Mount Charlotte was phased out, though the old tunnels still shape how the pit is mined.

In 2019 the operation poured its 50,000th gold bar, taking the Golden Mile past 60 million ounces since the first lease was pegged, and produced 456,000 ounces that year. It became wholly Australian-owned in January 2020, and since 2021 Northern Star Resources has run it alone. The approved Fimiston South project, with new cutbacks named Great Boulder and Ivanhoe after those first leases, extends the mine's life to 2034.

The Super Pit Lookout is one of the most popular attractions in the Goldfields, for the view of a working mine and the chance of a blast. The first lookout was a fenced platform near the old Hainault Tourist Mine; it has moved as the pit has grown, and for Fimiston South a new one is being built with an access road off Mount Monger Road. Hannans North Tourist Mine has blast footage, a decommissioned haul truck and a scale model of the pit.