Bauxite (Aluminium)

• Bauxite
• Resources
• Accessible EDR
• JORC Reserves
• Exploration
• Production
• World Resources
• Industry Developments

Bauxite is a heterogeneous naturally occurring material from which alumina (Al₂O₃) and aluminium are produced. The principal minerals in bauxite are gibbsite (Al₂O₃.3H₂O), boehmite (Al₂O₃.H₂O) and diaspore which has the same composition as boehmite but is denser and harder. Australia is the world's largest producer of bauxite.

The Weipa (Qld) and Gove (NT) bauxite mines have close to 50% available alumina and are amongst the world's highest grade deposits. The Western Australian deposits in the Darling Range and the undeveloped Mitchell Plateau are relatively low grade, at around 30% available alumina.

Over 85% of the bauxite mined globally is converted to alumina for the production of aluminium metal. An additional 10% goes to nonmetal uses in various forms of specialty alumina and the remainder is used for nonmetallurgical bauxite applications (e.g. commercial applications as abrasives and refractories). In almost all commercial operations, alumina is extracted through refining bauxite in a wet chemical caustic leach process known as the Bayer process. Alumina is smelted using the Hall-Heroult process to produce aluminium metal by electrolytic reduction in a molten bath of natural or synthetic cryolite (NaAlF₆).

Australia's aluminium industry is a highly integrated sector of mining, refining, smelting and semi-fabrication centres and is of major economic importance nationally and globally. The industry consists of five bauxite mines, seven alumina refineries, six primary aluminium smelters, 12 extrusion mills and two rolled product mills producing sheet, plate and foil. The industry is geared to serve world demand for alumina and aluminium with more than 80% of production being exported. Figures on the value of industry exports are collated half-yearly by the Australian Bureau of Statistics while the Australian Aluminium Council compiles monthly updates on bauxite, alumina and aluminium exports.

Vast resources of bauxite located in the Weipa and Gove regions adjacent to the Gulf of Carpentaria and in the Darling Ranges south of Perth underpin the long-term future of Australia's aluminium industry. Deposits in these regions rank among the world's largest identified resources in terms of extractable alumina content. Bauxite deposits at Mitchell Plateau and Cape Bougainville in the north of Western Australia are uneconomic to develop at present, but are a significant potentially viable future resource.

EDR of 5.7 Gt in 2006 was relatively unchanged from the previous year with the nett effect of exploration drilling adding to mineral resources and offsetting depletion through production. Movement in sub-economic and inferred resources also was static.

Less than 5% of bauxite EDR is inaccessible for mining. This represents small areas of the Darling Range in Western Australia within mining leases where bauxite is not available for extraction for environmental reasons. The ratio of AEDR to current mine production shows the resource life for existing bauxite operations on average is around 70 to 75 years. However, the potential of unexplored regions is likely to extend resource life well beyond this time.

Approximately 33% of AEDR comprises JORC code ore reserves as reported by industry. The remaining represents resources assessed by Geoscience Australia as being economically recoverable from measured and indicated categories of mineral resources, as defined under the code and other classification systems used by non-listed ASX companies. The surface expression of bauxite and confidence in lateral continuity of thickness and grade make it possible in certain terrains to classify some inferred resources as EDR.

Data relating to exploration for bauxite specifically are not available nationally.

Australia was the World's leading producer of bauxite and alumina, and the fifth largest aluminium producer. Production totalled 62 Mt of bauxite or 36% of world production, 18.4 Mt of alumina or 28% of world production and 1.9 Mt of aluminium or 5.8% of world production.

Production of bauxite at Weipa in 2006 was a record 16.1 Mt, 4% higher than in 2005. This increase was a result of the ongoing ramp up of the NeWeipa project, which delivered increased production from both the East Weipa and Andoom mines.

Based on USGS data for other countries, Australia's demonstrated bauxite resources of 7.8 Gt rank second in the world after Guinea with 8.6 Gt and ahead of Brazil with 2.5 Gt, Jamaica with 2.5 Gt and China with 2.3 Gt.

The 2006 sustainability report on Australia's bauxite, alumina and aluminium industries was being released by the Australian Aluminium Council in mid 2007. The report, the third in a series, documents how the industries are using physical resources and the impacts of that use along with how they are managing outputs and working to reduce the impact of production processes.

Companies engaged in Australia's bauxite-alumina-aluminium industry continued to respond to the needs of increased trade during 2006. At Weipa a second shiploader was commissioned to ensure reliability of bauxite supply to customers and Rio Tinto Marine committed to purchasing three bulk ore carriers to be used primarily for shipments from Weipa to Gladstone.