The Oraparinna barite mine is about 165km northeast of Port Augusta, and about 500km north of Adelaide in SA. The deposit also includes sandstone and dolomite.
Production began at Oraparinna in 1940.
Normandy Industrial Minerals operated the deposit from 1984, before transferring the mine to Sibelco subsidiary Unimin Australia in 2000.
Oraparinna has continued to be Australia’s largest supplier of industrial-grade barite. The mine comprises seven underground levels working a system of veins between 1m and 2m wide. These veins have developed in tensional fractures within Adelaidean Wilpena group sediments, in a graben structure extending from the north-eastern corner of the Oraparinna diapir.
Ore is trucked 160km to a treatment plant at Quorn where three industrial grades of barite (A, Standard and B, depending on colour), are produced for use in surface coatings, plastics fillers and mould coatings at the Olympic Dam mine site. Some A and Standard grade material is trucked to Gillman in suburban Adelaide for fine milling.