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...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...the water component of the slurry penetrated up to two metres deep carrying with it the toxic metals. [refers to Minera Alumbrera (joint venture Xstrata, Wheaton River Minerals, Northern Orion Resources)]