The mining of opal began commercially in the late nineteenth century in Australia.
The precious gemstone appears in both sedimentary and exothermic rocks. The bulk of Australia’s opal production is derived from sedimentary opal deposits. This is where Australis Fire Opal is different as Australis Fire Opal is found in exothermic rocks. Opals are usually found at shallow depths, normally less than 30 meters in very rocky and remote areas in which there have been some considerable amount of silica .
As opal is not found on the surface, or at least very rarely, miners in the early days used crude methods to mine opal.
The early miners simply used shaft sinking method with picks and shovels. A shaft is sunk straight down until some promising “opal dirt” is discovered. Opal is normally found in what is called “opal dirt.” This opal dirt is mostly found under a layer of very hard sandstone.
After such a find, the miner then branch out sideways, following the “level” of opal. Crude instruments such as handpick are used delicately to extract any opal found. This was often a two-man operation. It often consists of one man in the hole and another at the top to wind the windlass and haul out the dirt.
Sinking a shaft is still relatively a popular form of opal mining. While this is one of the most effective ways of finding opal, it is also the most laborious. The length of the shaft could be short and range from three meters to as long as 20 meters. Usually, the miner begins burrowing away very slowly and carefully, forming a horizontal tunnel and hope to find a tiny seam of precious opal, or scattered ‘nobbies’. A variety of miner’s tools are needed, this include a hand windlass or motorised winch that is placed over the hole to lift dirt to the surface. Some miners use an expensive vacuum-cleaner apparatus, called a ‘blower’.
Open-cut mining is another opal mining method. This opal mining technique is created by running bulldozer over the land area of the suspected deposit. Thus slicing through thin layers of sandstone until the opal level is reached. Although this method is more expensive than shaft mining, the chances of finding opal are greatly increased.
Noodling is another way of finding opal. A noodler is a person who goes over what other miners have missed when after blasting. They use crude and basic instruments such as rake and sieve for tools, often in open cut mines to scavenge and sieve out opal. Some miners use this method by allowing opal dirt to pass through large conveyor belt and used ultra-violent light to pick out opals
Puddling and Rumbling is another opal mining method. A puddler is a large mesh-lined drum attached to a motor. This technique works by separating opal dirt and opal stones in a large spinning drum. In rumbling, large amounts of opal dirt are sifted through in a short time by using a mesh tray.
At Australis Fire Opal we don’t actually mine, as the opal is very close to the surface (after 60 million years of erosion). The ground is very hard dry exothermic rock this means Australis Fire Opal is very dry non-hydrated opal; it has very low water content and great clarity meaning its far less prone to cracking.
The Australis Fire Opal mine site also has sedimentary rocks making it a very rare and unique site, The complete geological history of the area is currently being researched to help uncover the mystery of this amazing opal.