"Wuda - a Small Coal Mining Town in North... " a Wuda Travel Page by claudia1975

Coal fires exist in many countries world wide and were aldready mentioned in travel reports of Marco Polo. Outcropping coal seams in arid (warm and dry) regions can start to ignite already at temperatures as low as 70 deg Celsius. The coal seam starts to burn and the fire eats into the coal seam below the surface. In many regions huge coal seams are burning and smoldering underground.
In China the main coal fire areas stretch along the coal mining belt in China, which extends for 5000km from East to West along the North of the country. Here more than 50 coal fields affected by coal fires have been identified. At present in China an estimated 20-30 Mio. tons of coal burn each year. This corresponds to the amount of Germany’s annual hard coal production. Actually, the tenfold amount of the resource is lost, since coal adjacent to a coal fire becomes inaccessible. The economic loss of the valuable resource in China is estimated to sum up to total 4.2 Billion tons since 1960. Thus, China faces the world’s biggest problem of coal fires both in terms of the spatial area affected and the amount of coal lost each year.

Besides the economic loss, coal fires pose many environmental threats. The fires produce large amounts of greenhouse-relevant and partially toxic gasses including CO2, CH4, NOx, N2O, CO and SO2. According to most recent estimations coal fires in China contribute about 0.1% to 0.2% of the annual human induced CO2 emissions globally. They contribute 12% of all Chinese coal-based carbon emissions in the form of CO2. In addition, coal fires lead to the degradation of their direct surrounding area through significant aerosol input to water sources and agricultural areas. Additionally, the toxic fumes released pose a threat to the health of the local inhabitants. Furthermore, land subsidence can occur due to the loss of volume underground, when a coal seam, supporting several layers of overlying strata, turns into ash. The resulting slow or very sudden subsidence can be a threat to infrastructure, local inhabitants and miners. Each year, several thousand workers are killed in mining accidents, which are quite often also coal fire related.

Coal mining in China is a tough job. Especially in rural areas industrialization is low and so are safety standards. Coal miners work 6 days a week in 8 hour shifts - even in the night. However, the average wage working in a state run mine is (for Chinese standards) not too bad and many people earn a living with it to support their families. A coal miner earns more than a rural middle school teacher. However, many miners risk their health and life.
Women are not allowed to work underground in the mines. Usually it is a womens job to load the coal from a coal pile in front of the mine entrance onto a truck. The truck will transport the coal to electricity plants or other factories.

The institute I work at undertakes research on coal fires and the implementation of methods to map, monitor and finally extinguish these fires to save the valuable ressource coal as well as to reduce the gasseous emissions.
We use remote sensing satellite data (which looks like photographs or thermal images from space) to find the coal fires, to estimate their size and burning intensity. Furthermore, we do yearly field work campaigns to investigate the fires dynamics (do they grow or shrink etc.) and many geophysicists and mining experts test methods to extinguish the fires. Water is - in these dry and remote areas - often not available and due to chemical reactions also not the best option. If you are interested in our research see:
http://www.coalfire.caf.dlr.de/intro_en.html