By Nick Bryant
BBC News, Sydney
Aborigines in Australia have won a court fight against the Anglo-Swiss mining giant Xstrata.
Xstrata had planned to divert a river to allow for the expansion of a zinc mine in the Northern Territory.
A Federal Court decided that the government did not follow the proper process in allowing the mine's expansion to go ahead in 2006.
Some Aboriginal leaders cried with happiness when the ruling was handed down by the Federal Court in Sydney.
They had fought a long battle to overturn the government's decision to allow the diversion of the McArthur River in order to expand the mine.
The company had wanted to divert the river to extend the life of the mine by turning it from an underground to an open cast operation.
Along with environmentalists, indigenous groups had argued that there was a risk during the rainy season that the McArthur River would be contaminated by seepage from mining.
They also argued that the government had not followed the proper process in granting approval for the scheme and that there was a lack of consultation. The federal court ruled in their favour, citing a lack of due process.
Over 5km (3 miles) of the river has already been diverted, and the traditional owners are now demanding that it be returned to its original course.
"We want the river put back," said one Aboriginal leader.
Xstrata has expressed disappointment at the ruling, and had indicated beforehand that it might be forced to close the mine.
An industry group, the Northern Territory Resources Council, described the ruling as a huge blow for Australia's mining industry.