Robledo, MF 2012, 'A successful heap leach reclamation under extreme conditions – a case study', in AB Fourie & M Tibbett (eds), Mine Closure 2012: Proceedings of the Seventh International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 317-327, https://doi.org/10.36487/ACG_rep/1208_29_Robledo
(https://papers.acg.uwa.edu.au/p/1208_29_Robledo/)
Abstract: The Tambo Mine is located in the IV Region of Chile, approximately 180 km east of La Serena in the Chilean Andes, close to the Argentinean border at approximately 4,040 metres above sea level (masl). Through its life, the property has had several owners. Barrick Gold Corporation acquired the property in 1994. The Tambo open pit mining/milling operation began in 1995 and ceased in 2000. In 2001, Chilean authorities approved the Tambo Mine Closure Plan submitted by Barrick.
Closure activities at El Tambo Mine included the reclamation of a pre-existing heap leach facility that operated between 1986 and 1994. This facility has a total area of 7.5 ha and contains approximately 3 million tonnes of cyanide leached ore. The climate is typically mountainous, type tundra, characterised by major diurnal variations in temperature; the peak summer maximum temperature is 24°C, and the winter peak minimum temperature is -21°C. Precipitation occurs mostly as snow during April to September; peak annual snow fall range up to 817 cm.
This paper documents the heap leach reclamation under these extreme conditions in order to develop and implement the most appropriate engineering solutions for the closure to fulfil the objective of “to prevent and reduce the risks for human health and the environment, as the result of the closure and subsequent abandonment of the mining facilities”. Activities included slope re-grading, the construction of a cover system, and construction of surface water management infrastructure. In addition, a passive water treatment facility was constructed to manage the residual effluents chemistry (cyanide content) to comply with discharge limits.