Bauxite, alumina, aluminium (continued)

A third major source of bauxite and alumina is the Gove deposit in the Northern Territory, where 6 Mt/yr of bauxite is mined to produce 1.1 Mt/yr of alumina and substantial exports of bauxite. Operations commenced in 1971 under the Nabaico consortium which includes Alusuisse.

Smelting developments have been continuous over some 30 years, commencing with Comalco's Bell Bay (first production 1955, present capacity 125,000 t/yr); Alcoa's Point Henry (1963, 170,000 t/yr); Alcan's Kurri Kurri (1969, 150,000 t/yr); Comalco's Boyne (1982, 208,000 t/yr); Pechiney's Tomago (1985, 230,000 t/yr); Alcoa's Portland (1986, 150,000 t/yr). The total capacity of 1 Mt/yr of aluminium as against 40 Mt/yr of bauxite and 10 Mt/yr of alumina suggests significant opportunities for a further expansion of smelting capacity within Australia when world demand again increases, having regard to plentiful energy reserves and certain environmental advantages over other world producers. It may be said that all Australian alumina and aluminium plants operate at a high technological level and that research and development achievements continue to be significant at both plant and laboratory levels. Some selected instances would include the following:

1. the modification of the standard Bayer and Hall-Heroult processes to accommodate the chemical and physical characteristics of the Weipa, Darling Ranges and Gove bauxites
2. the refinement of processing by Queensland Alumina in treating both monohydrate and trihydrate ore which reduced the digestion time and the amount of reactive silica taken into solution
3. the investigation of alternative non-conventional production routes from bauxite to aluminium
4. the development of a process to enable anode grade carbon to be produced from Australian coal
5. the production of calcined bauxite for export to the abrasives industries, and proppants for use in stimulation of oil and gas well recovery
6. the projected extraction of gallium from the Bayer liquor at the Pinjarra refinery in an amount which could constitute the world's greatest source of supply
7. the extraction of high grade kaolin from a formation underlying the Weipa bauxite and the tuning of existing processes for production of premium paper coatings
8. the development of Alcoa's Del Park mine in the Darling Ranges of a systemof mobile crushing stations feeding direct to a 13 km overland conveyor
9. the major rehabilitation of mine sites -more than three million trees have been planted in the Darling Ranges and more than 60 timber species have been planted at Weipa in the regeneration of 3300 hectares out of a total of 4800 hectares mined.

Australian Academy of Technological Sciences and Engineering