The 1999 Social and Environment report uses a different measuring system, so comparisons cannot be made. This makes it less likely cyanide compounds will break down in sunlight. There is a serious acid rock drainage problem at the Kelian mine. Manganese levels have exceeded permitted levels on a number of occasions during the past few years. This year Rio Tinto plc has not released figures in the Social and Environmental report.
Local people depend on river water as a supply for drinking, cooking, bathing and fishing.
Indigenous Dayak people found gold in the upper reaches of the Kelian River in 1948. The original miners were joined by many more as word spread. By the 1970s there were around 4,000 people living around the Kelian River, including 2,000 small-scale miners. The local Dayak Bahau community made an agreement allowing other communities to prospect for gold on their land. These people made a good living and relations between groups were harmonious until the late 1970s when the Indonesian government allowed foreign mining companies to explore for gold.