Eco-environmental dynamic monitoring and assessment of rare earth mining area in Southern Ganzhou using remote sensing

Abstract

Although development of the rare earth mining industry has resulted in significant contributions to regional economies, such benefits have also caused severe environmental problems. In order to create land cover maps and thereby monitoring the changes in eco-environmental impacts caused by rare earth mine exploitation in southern Ganzhou, China, during 2000-2010, object-oriented classification was conducted using SPOT1/2/5, Landsat7, and ALOS satellite images. A retrospective approach was also used to reduce the amount of false change information and thus efficiently extract the change information in this region. The total rare earth mining area increased from approximately 36.02 km2 in 2000 to 49.58 km2 in 2010. The results indicate that the rare earth mining area was mainly distributed in the towns of Ling Bei, Zu Dong, and Guimei Shan. During 2000-2005, the rare earth mining area expanded rapidly before slowing in 2005-2010 due to implementation of a reclamation program. The results also showed that most newly expanded rare earth mine areas were converted from forests, whereas the major reclaimed areas were farmland. Rapid development of rare earth mining is shown to cause severe environmental problems including vegetation destruction, biomass change, land degradation, and landscape fragmentation in addition to potential risks such as soil erosion and landslides.