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Asbestos

state_asbestos_sm.jpg (11544 bytes)Asbestos is a generic name for a group of fibrous silicate minerals including the serpentine group mineral chrysotile (Mg3Si2O5(OH)4; white asbestos) which accounts for ~98% of the world's asbestos production, and the amphibole minerals crocidolite (Na2(Fe,Mg)5Si8O22(OH)2; blue asbestos) and fibrous tremolite (Ca2Mg5Si8O22(OH)2). The flexibility and tensile strength of the mineral fibres, combined with excellent insulation properties and a high degree of resistance to heat and chemical attack, make asbestos suitable for a wide variety of uses including brake linings, clutch facings, gaskets, fire-proof products and reinforcing material in cement products.

World production (1.9 Mt in 1999) is in decline due to concerns over health and safety. Substitutes, including minerals such as wollastonite, are increasingly used wherever possible.

South Australia has produced only minor quantities of asbestos. The earliest recorded production was from a deposit near Robertstown in 1894 and, up until 1950, ~1000 t of mainly crocidolite were mined from a series of small pits in the Robertstown-Truro-Lyndoch area 50-120 km north of Adelaide. These deposits are hosted by carbonate rocks; Skillogalee Dolomite and Auburn Dolomite of the Burra Group in the Robertstown area, and dolomitic limestone of the Cambrian Hawker group near Truro. The asbestos occurs in narrow shear zones up to ~1 m thick. It is most unlikely that these deposits will be worked again.

Additional Reading

Hiern, M.N., 1976. Asbestos - South Australia. In: Knight, C.L. (Ed.), Economic geology of Australia and Papua New Guinea, 4, Industrial minerals and rocks. Australasian Institute of Mining and Metallurgy. Monograph Series, 8:11-14.

King, D., 1957. Investigation of asbestos deposits in the Robertstown and Truro districts. Mining Review, Adelaide, 103:58-73.