Bauxite

Bauxite is the main raw material used in the commercial production of alumina (Al2O3) and aluminium metal globally, although some clays and other materials can also be utilised to produce alumina. Bauxite is a heterogeneous, naturally occurring material of varying composition that is relatively rich in aluminium. 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, representing 28% of global production in 2012. The large bauxite resources in the Gulf of Carpentaria at Weipa (>3000 Mt) in Queensland and Gove (>200 Mt) in the Northern Territory have average grades between 49% and 53% Al2O3 and are amongst the world's highest grade deposits. Other large deposits (>500 Mt) are located in Western Australia in the Darling Range, the Mitchell Plateau and at Cape Bougainville, of which the latter two have not been developed. The bauxite mines in the Darling Range have the world's lowest grade bauxite ore mined on a commercial scale (around 27-30% Al2O3). Despite the low grade, the mines accounted for 23% of global alumina production. JORC-compliant bauxite resources also occur in New South Wales and Tasmania but these are small (<25 Mt).

More than 85% of the bauxite mined globally is converted to alumina for the production of aluminium metal. An additional 10% goes to non-metal uses in various forms of specialty alumina, while the remainder is used for non-metallurgical bauxite applications. In most commercial operations, alumina is extracted (refined) from bauxite by 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 is becoming less vertically integrated, however, owing to the rise of independent smelters, particularly in China.

The Australian industry consists of:

  • five long-term bauxite mines at Weipa, Gove, Huntly, Boddington and Willowdale (Figure 3.1)
  • seven alumina refineries at Gove in the Northern Territory, Yarwun and QAL in Queensland, Kwinana, Pinjarra, Wagerup and Worsley in Western Australia
  • five primary aluminium smelters (previously six before the 2012 closure of Kurri Kurri, New South Wales) at Bell Bay in Tasmania, Boyne Island in Queensland, Tomago in New South Wales and Portland and Point Henry in Victoria
  • 12 extrusion mills located in New South Wales, Victoria, South Australia, Queensland and Western Australia
  • two rolled product plants producing aluminium sheet, plate and foil in Victoria.

The industry in Australia is geared to serve world demand for alumina and aluminium with more than 80% of production exported. Transport, packaging, building and construction provide much of the demand for the metal in Australia.

Figure 3.1 is a map of Australia showing the names, locations and sizes of major bauxite deposits. The map also shows the state boundaries and capital cities as well as the major geological provinces of the country. Bauxite deposits are displayed as filled orange circles split into six sizes according to the total in situ resources of bauxite. The six sizes are labelled '50 to 100 million tonnes', '100 to 500 million tonnes', '500 to 1000 million tonnes', '1000 to 2000 million tonnes', '2000 to 3000 million tonnes' and 'greater than 3000 million tonnes'. In addition, some circles are drawn with a heavy black line indicating that these deposits are operating mines. The map shows the greatest concentrations of significant bauxite deposits in Australia occur in Queensland on the west side of the Cape York Peninsula and in Western Australia in the Darling Range near Perth and along the Kimberly Coast in the north of the state. Operating mines are located in the Darling Range, at Weipa on the Cape York Peninsula and on the opposite side of the Gulf of Carpentaria at Gove in the Northern Territory.

Figure 3.1 Australia's major bauxite deposits based on total Identified Resources.
Source: Geoscience Australia.

Resources and Reserves

Table 3.3 Australia's resources of bauxite and world figures as at December 2012.
Units JORC Reserves (% of EDR) Economic Demonstrated Resources (EDR) Paramarginal Demonstrated Resources Submarginal Demonstrated Resources Inferred Resources Accessible EDR Mine Production in 2012 World Economic Resources World Mine Production in 2012
Source: Geoscience Australia, the Bureau of Resources and Energy Economics and the United States Geological Survey; Paramarginal and submarginal demonstrated resources are subeconomic at this time; Mt = million tonnes.
Mt 2145 (34%) 6281 144 1429 1474 6281 76.3 28 000 263

Figure 3.2 comprises two pie charts side by side. The one on the left shows the percentage of Economic Demonstrated Resources (EDR) of bauxite held by each state and territory in Australia as at December 2012. The chart on the right shows the percentage of total bauxite resources held by each state and territory in Australia as at December 2012. Queensland has the most bauxite EDR with 61% followed by Western Australia with 35%. However, Western Australia has the greatest total bauxite resources with 56% followed by Queensland with 42%. The Northern Territory, New South Wales and Tasmania also have small proportion of bauxite resources.

Figure 3.2 Percentages of Economic Demonstrated Resources and total resources of bauxite held by the states and territories in Australia. Total resources comprise all Demonstrated and Inferred Resources. Numbers are rounded so might not add up to 100% exactly.
Source: Geoscience Australia.

World Ranking

Table 3.4 World economic resources for bauxite.
Rank Country Bauxite (Mt) Percentage of world total
Source: United States Geological Survey and Geoscience Australia; Mt = million tonnes; Figures are rounded to nearest 10 million tonnes; Percentages are rounded so might not add up to 100% exactly.
1 Guinea 7400 26%
2 Australia 6280 22%
3 Brazil 2600 9%
4 Vietnam 2100 7%
5 Jamaica 2000 7%
6 Indonesia 1000 4%
7 India 900 3%
8 Guyana 850 3%
9 China 830 3%
10 Greece 600 2%
  Others 3720 13%
  Total 28 280  
Table 3.5 World production for bauxite.
Rank Country Bauxite (Mt) Percentage of world total
Source: United States Geological Survey and the Bureau of Resources and Energy Economics; Mt = million tonnes; Percentages are rounded so might not add up to 100% exactly.
1 Australia 76 30%
2 China 48 19%
3 Brazil 34 13%
4 Indonesia 30 12%
5 India 20 8%
6 Guinea 19 7%
7 Jamaica 10 4%
8 Russia 6 2%
9 Kazakhstan 5 2%
10 Venezuela 5 2%
  Others 4 2%
  Total 257  

Trends

EDR of bauxite increased in 1989 as a result of the delineation of additional resources in deposits on Cape York Peninsula in Northern Queensland ('a' in Figure 3.3). Decreases in bauxite EDR in 1992 resulted from the reclassification of some resources within deposits on Cape York Peninsula to comply with requirements for the JORC Code ('b' in Figure 3.3).

Figure 3.2 comprises two pie charts side by side. The one on the left shows the percentage of Economic Demonstrated Resources (EDR) of bauxite held by each state and territory in Australia as at December 2012. The chart on the right shows the percentage of total bauxite resources held by each state and territory in Australia as at December 2012. Queensland has the most bauxite EDR with 61% followed by Western Australia with 35%. However, Western Australia has the greatest total bauxite resources with 56% followed by Queensland with 42%. The Northern Territory, New South Wales and Tasmania also have small proportion of bauxite resources.

Figure 3.3 Trends in Economic Demonstrated Resources for bauxite since 1975.
Source: Geoscience Australia.

Resource to Production Ratio

Table 3.6 Indicative years of bauxite resources (rounded to the nearest 5 years) as a ratio of Accessible Economic Demonstrated Resources divided by the production rate for each year.
Year 1998 2003 2008 2009 2010 2011 2012
Source: Geoscience Australia.
AEDR/Production 70 90 85 85 80 80 80