Other than agriculture and tourism, the main economic activity in this vast and sparsely settled area is mining. Owing to the complete absence of mountain building and glaciation since the Permian (in many areas since the Cambrian) ages, the outback is extremely rich in iron, aluminium, manganese and uranium ores, and also contains major deposits of gold, nickel, iron, lead and zinc ores. Because of its size, the value of grazing and mining is considerable. Major mines and mining areas in the outback include opals at Coober Pedy,Lightning Ridge and White Cliffs, metals at Broken Hill, Tennant Creek, Olympic Dam and the remote Challenger Mine. Oil and gas are extracted in the Cooper Basin around Moomba.
In Western Australia the Argyle diamond mine in the Kimberley (Western Australia) is the world's biggest producer of natural diamonds and contributes approximately one-third of the world's natural supply. The Pilbara region's economy is dominated by mining and petroleum industries. Most of Australia's iron ore is also mined in the Pilbara and it also has one of the world's major manganesemines.