Coober Pedy - Wikipedia

Opal Mining South Australia

South Australia / June 1, 2017

South Australia, by weight would produce most of Australia's opal. Fields such, , , and produce stunning White and Crystal Opals.

Coober Pedy opal fields

Coober Pedy produces the bulk of the world's white opal. The opal mining fields of Coober Pedy lie in the outback of South Australia, Stuart Range, 750 km north of Adelaide. Many of the locals in Coober Pedy prefer to live underground in dugouts where it is cool in summer and warm in winter. The township of Coober Pedy is situated in a stony, treeless desert on the edge of the Stuart Ranges. Very little plant life exists in the town due to the region's low rainfall, high cost of water, and the infertile soils.

Opal was discovered in 1915 by a 14-year old boy who was camping with his father's gold prospecting party and, by 1916, Big Flat was established as the principal field. After the First World War, an influx of miners caused a major increase in production. The dugout style of living introduced by these ex-soldiers gave the field its name which is derived from the Aboriginal 'okupa piti' meaning 'white man's burrow'.

Opal at Coober Pedy is found in deeply weathered white to mauve Bulldog Shale of Cretaceous age. Miners call the light, porous host rock 'sandstone'. Within the sandstone, opal may be found as veins in horizontal' levels' or in steeply dipping 'verticals' down to 25 m below the surface. Distribution is unpredictable and opal may not persist from one claim to the next. Coober Pedy is the world's largest producer of precious opals.

Andamooka opal fields

Two boundary riders from Andamooka Station discovered opal in Andamooka in 1930. The field was slow to go into production because of the harsh climate and world events in the 1940's, but by 1962 an estimated 800 miners were working on the fields. Situated 520 km north of Adelaide, Andamooka miners work over an area of about 52 square kilometres on the Arcoona plateau in shafts, large bore-holes, open-cut excavations and small tunnels. The opal is mined from three to ten metres down on the ancient seabed. From 24 separate fields, opalised shells, stones and dinosaur bones are still being brought to the surface. Andamooka opal is considered to be the world's most stable opal.

The climate is typical of semi-desert environments, and between March and November, the weather is very pleasant with warm days and cold nights. From December to February the weather warms up and summer temperatures range from 35C in the shade, with occasional dust storms. The annual rainfall around Andamooka is minimal, at around 175mm (5inches) per annum.

Mintabie opal fields

A well sinker, named Larry O'Toole, is credited with finding the first opal in Mintabie in the 1920's. Mintabie is the newest opal field, discovered in the 1920's, but was not aggressively worked until 1978, when good opal began to be found. Mintabie is situated 180km south of the Northern Territory border, and approx. 300km north of Coober Pedy.

Mintabie's harsh climate and lack of water discouraged mining until mid 1970. In 1976, explosives and large machinery were brought to the field. In October 1981, the Pitjantjatjara Land Rights Act came into force and Mintabie became part of a large area of freehold Aboriginal land. This Act has continued to have an effect on the Mintabie way of life.

During the First World War, Aborigines sold black opal at Coober Pedy which probably came from Mintabie, 350 km to the northwest. The population was roughly 1, 500 residents in 1988, but has declined recently due to lack of production. Today's population stands at around 250.

Most opal mining in Mintabie is done via open-cut methods. It is an unique field in that the township& opal fields are located on freehold Aboriginal land. Temperatures in the area range from below zero, to the high 40's.

Lambina opal fields

Old miners claim that opal was first discovered at Lambina during the depression years of the early 1930's. A minor rush in the late 1980's occurred following discoveries by some miners at Seven Waterholes diggings.

Mining continued at varying levels until mid 1990. However, the discovery of high quality stones in 1996 led to a rush of claims being pegged. Nevertheless, before many of these claimed could be processed, the Wik native title decision halted any new mining. In December 1997, miners were informed that a native title claim would be lodged over the entire Mintabie area. Negotiations between miners and native title holders since then have allowed mining to continue.

Lambina now supports a population of around 300 and produces a major portion of South Australia's opal.

Source: www.opalsdownunder.com.au