A pamphlet produced by the Australian Department of Mines and Energy
titled Opal in South Australia, describes the mining process as: "Opal is one
of the few minerals which can still be extracted economically by a miner working
alone." "The simplest form of mining is by shaft sinking with a pick and
shovel. Droving along the level is then carried out with picks and explosives. When traces
of opal are found a handpick or screwdriver is used."
"Nowadays most shafts are sunk by Calweld-type drills which are used to excavate
holes about one meter in diameter using an auger bucket. This rig is also used for
prospecting and the opal fields are pitted with abandoned Calweld drill holes."
"Waste material, or mullock, form the shafts and drives was originally lifted in
buckets by hand windlass, but power winces or automatic bucket tippers, known as self
unloaders, are now used. Truck-mounted blowers, which operate like vacuum cleaners, are
also used for lifting mullock."
"Since 1970, there has been a rapid increase in the use of mining machines.
Tunneling machines with revolving cutting heads and small underground front-end loaders,
call boggers have been introduced."
"Bulldozers are employed to remove overburden and expose the level where it is
shallow. Spotters follow behind watching for opal and the seam is then worked over
by handpick."
