Coal fires revisited: The Wuda coal field in the aftermath of extensive coal fire research and accelerating extinguishing activities

The Wuda coal mining area in Inner Mongolia Autonomous Region, China, is one of the largest coal fire areas world-wide. At the same time it is also one of the most extensively researched ones. The sub-surface coal fires raging in the underground coal seams of the syncline are located directly west of the town of Wuda. The fires have been mapped in situ, based on remote sensing data, as well as based on geo-physical survey all throughout the years 2001 to 2005. Numerous publications depict the situation during that time. In the present study we assess the current situation in Wuda coal field five years after the last field campaigns, under nowadays on-going and accelerating extinguishing activities. We present the results of coal fire dynamics assessment based on in situ mappings between 2004 and 2010, the analyses of changes in mining infrastructure between 2005 and 2012, as well as land cover change in the area from 2005 to 2012. Newest high resolution multi-spectral and panchromatic Quickbird data, as well as time series of Quickbird data supported this endeavor. We furthermore present the result of semi-structured interviews undertaken with members of the local mine directorate of the Wuda syncline. All jointly analyzed data indicate that the Wuda coal fires tend to move eastwards within the syncline, meaning that they move along the dip of the coal seams to greater depths. Furthermore, mining related infrastructure is clearly moving from the West to the East as well. Despite large funds spent on fire extinguishing, only few fires remain permanently extinct, while other fire areas increase in size. The former land cover structure in the arid syncline does not exist anymore - extinguishing activities have led to a complete 'turn-over' of all material in the region. The coal fire problem in Wuda area remains a pressing one. (C) 2012 Elsevier B.V. All rights reserved.