Remote Sensing Detection For Subsidence-resulted Water Body And Solid-waste Dump In Yanzhou Coal Mining Area

Satellite remote sensing plays an important role in environmental monitoring for mining area. Yanzhou coal mining area, which lies in Luxinan Plain of Shandong Province, has an annual yield of 3000×104t. It makes a strong environmental and ecological impact on surface because of high-intensity mining for many years. Mining subsidence resulted surface water body and coal and solid-waste dump, which take a large area of farmland, are the two main aspects of the impact. This paper selects a group of multi-temporal TM/ETM+images (acquired in 1987 and 2002 respectively) from LandSat as the information source to study the change information of the two aspects during the past 15 years.The images acquired in 2002 are taken as an example. Normalized Difference Water Index (NDWI) is got firstly; then, water information could be extracted with appropriate threshold value according to NDWI. What is mixed in water is coal and solid-waste dump including coal gangue, and fly ash and so on. After analyzing the spectral characteristics, DN value 40 in band 5 is chosen as threshold value to distinguish coal and solid-waste from water. Mining subsidence resulted water body and coal and solid-waste dump are of different characteristics in temperature change and heat radiation. Using some formula-transformation, the ground brightness temperature is retrieved from DN in thermal infrared band (band 6 of TM/ETM+ images) which could reveal the difference of thermal field of land surface. The result shows that because of great temperature difference (more than 10K), the mixed information of water body and coal and solid-waste dump is easy to be specified. The methods are also applied for the satellite remote sensing images of Yanzhou coal mining area acquired in 1987. It is founded that in Yanzhou mining area, the area of solid-waste dump and mining subsidence resulted water body in 2002 is 0.90 times and 2.87 times greater than that in 1987 respectively. The main changed areas of mining subsidence resulted water bodies are located nearby Nantun coal mine, Xinglongzhuang coal mine and Dongtan coal mine. The main change areas of solid-waste dump are around Dongtan, Baodian and Jier coal mine.