The Yanacocha Gold Mine began operations in the department of Cajamarca in 1993. Yanacocha, the largest gold mine in South America, comprised of six open pit mines, four leach pads and three processing facilities. In June 2000, a contractor to Minera Yanacocha spilled 151 kg of elemental mercury along a 41 km stretch of road between the mine site and the town of Choropampa. A number of local people, unaware of the nature of the chemical, were exposed and subsequently experienced adverse health effects. In March 2006, 30 canal users jointly lodged a complaint with CAO requesting assistance in obtaining information about the current and potential impact of mining activities on the water quantity in the canals, rivers and streams surrounding the project. The petition expressed satisfaction with the collaborative process undertaken by the Mesa and CAO in relation to water management and an interest in extending these efforts through an independent mechanism such as CAO.