An earthquake on September 17, 2004 measuring 6.5 on the Richter scale caused a pipeline to break at the Alumbrera mine in Argentina, sending copper and gold concentrate into the Villa Vil river.

An unknown amount of mineral concentrate filled approximately 2 kilometres of the Villa Vil river, which provides water for domestic consumption and irrigation to the municipality of Andalgalá in Catamarca province. This caused great alarm within the community, according to local councilman Edgardo Salas. The pipeline begins at the Bajo La Alumbrera mine site and culminates in the province of Tucumán.

While the flood of concentrate – which according to local observers reached 12 metres in height – left a layer of solids on top of the riverbed and river banks (as can be seen in the photo), the water component of the slurry penetrated up to two metres deep carrying with it the toxic metals.

As a precaution, water supplies for irrigation and domestic use were cut in the whole area. Through a team of legal advisers, the inhabitants of Villa Vil in Andalgalá will present a complaint in Federal Court against the mining company, Minera Alumbrera Ltd. for “dissemination of dangerous waste” (as stipulated by Argentine Law 25,612).

Minera Alumbrera is 50% owned by Xstrata Copper, subsidiary of the Swiss company XStrata plc; Wheaton River Minerals Limited of Canada owns 37.5%, and Northern Orion Resources Inc., also Canadian, owns the remaining 12.5%.

The 316 kilometre mineral pipeline was constructed to transport concentrated copper and gold from the mine, in Catamarca, to the treatment and filtration plant and railway terminal, located near Tucumán. It has 3 pumping stations, and is designed to transport up to 103 tonnes of material per hour; the material moves at approximately 5 kilometres per hour. The pipeline has a 2 millimetre polyethylene outer shell, and a 6 millimetre inner polyethylene coating.

The pumps elevate the slurrry to a height of 2559 metres; from this height, it flows by gravity 150 kilometres to the Cruz Alta de Tucumán processing facility. There the water (60% of the slurry) is extracted and dumped into the Salí River, contaminating it with copper, chromium, arsenic, and uranium.

The spill follows legal action intiated by the Governor of Tucumán against Minera Alumbrera for the contamination of the Salí River. Julian Rooney, Vice President of Alumbrera, has been named by the Federal Court to answer pollution charges.

Meanwhile the Canadian media and the Ontario Securities Commission have made no investigation of the liability and responsibility of the Canadian companies involved.