Monitoring the environmental impact of mining in remote locations through remotely sensed data

Mining is an integral part of the development of many countries in the Asia-Pacific region and is associated with adverse environmental and social impacts. The monitoring of mining in remote locations is problematic due to difficulties of access. Satellite remote sensing is able to provide information on landscape transformation in a cost-effective way around large-scale mines. The PT Freeport Indonesia mine in Papua (Indonesia) is the world's largest copper-gold mine and previous studies have documented a range of impacts. A multi-temporal analysis of Landsat 5 imagery of the Freeport area was undertaken for the years between 1988 and 2004. Anthropogenic land cover changes were quantified by screen digitising polygons from three false colour composite images over this period to determine the area of forested land that had been cleared and the area that had been affected by mine-derived sediment transported by the Ajkwa River system. The results show that both settlement and sediment had radically altered land cover and together had led to a sixfold increase in the area of ultra-diverse lowland tropical rainforest cleared in the study area. The study highlights the utility of this method to monitor elements of the impact of large-scale mining and other extensive forms of resource exploitation such as deforestation in developing countries.