• Kwinana
    Kwinana
    Australia
  • Jamaica
    Jamaica
  • Aughinish
    Aughinish
    Ireland
  • Yarwun
    Yarwun
    Australia
  • Gladstone
    Gladstone
    Australia
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Alcan (now Rio Tinto) has had a long history in Jamaica, constructing two alumina refineries there in the 1950s. In 2001 Alcan sold its bauxite mining and alumina plants in Jamaica but kept responsibility for many of the bauxite residue sites with the intention of safely remediating them to an agreed standard and transferring ownership to the Government of Jamaica. The agreed objective was maximum biodiversity rather than housing or agricultural use.

October 2005
June 2010
September 2015

Jamaica

Rio Tinto

At one of the disposal sites in Jamaica, the bauxite residue had been deposited in depressions left after bauxite mining. When deposited, the residue had a solids content of approximately 20% but it was discharged in a way that in most cases, when full and aged, no residual pond water remained resulting in a relatively dry surface with a pH of about 11.

In 1996, trials were undertaken on a former pond; after working the surface to produce smaller nodules, plots were treated with gypsum. Just over a year after the gypsum was spread, poultry manure and ammonium sulphate was spread. Three months later seeding (including Bermuda Grass, Brachiaria, Lead Tree, Castor Bean and Logwood) was undertaken.

In 2004 a study found 53 species belonging to 28 families, dominated by Guinea Grass, Lead Tree and Christmas Bush; only Logwood and Lead Tree remained from the original species planted. The success of the Lead Tree is attributable to its nitrogen fixation ability. The growth form of the vegetation, slender trees, grasses, climbers and runners with rhizomes and stolons is typical of an early pioneer stage in succession and development.

In 2005 parts of the area were reinvigorated by additional gypsum and chicken manure and reseeding with Brachiaria, Bonavista Bean and Guinea Grass. By mid - 2011 there had been a dramatic improvement in the growth across the entire area; 56 species were found which is comparable to a “dry limestone forest” in Jamaica.

Following this trial, Rio Tinto adopted a very similar approach on the remaining ponds, which still comprised bare bauxite residue, and excellent revegetation has been found after three years.