Monitoring And Analyzing The Mining Impacts On Key Environmental Elements In Desert Area

The objective of this dissertation is to find the impact law of underground mining on the fragile environment at desert area. Therefore, the worldwide known Shendong mining area was taken as a case study area. The vegetation and water resource including the surface soil moisture, unsaturated zone water, and groundwater, were selected as the key environment elements based on abundant literature reviews. The spatiotemporal evolution law of which was monitored by integrating with RS, GIS, GPR, field investigation etc. The conclusions were made as follows.On large scale, monthly Series of MODIS-NDVI-250m/1km were summarized from 2000 to 2005, which showed the vegetation varied circannian, corresponding with the circannian variation of air temperature, rainfall, air pressure etc. Therefore, there was apparent relativity between NDVI and climate factors; however, vegetation is more susceptible to rainfall. Overall, the vegetation of study area varied regionally, and improved since 2002, and no abnormal was detected. On micro-scale, it was observed by both TM and field investigation that the vegetation of mined area was a slight less than the unmined area.The surface soil moisture of the study area was retrieved by advanced RS to further interpret the vegetation variation due to the underground mining. Compared with soil reflectance, soil wetness, topography wetness index, soil albedo, the apparent thermal inertia has a distinct relationship with soil moisture. For improving the resolution of predicted soil moisture, the soil temperature difference model was developed to model the soil moisture with higher resolution by method of apparent thermal inertia (ATI) and TM image. The ATI has stronger relationship between the observed soil moisture at depth of 10cm, than that of 20cm, and 40cm. Therefore, the square of correlation coefficients (R2) was improved to 0.789 by improved soil temperature difference model at depth of 10cm. Moreover, the nonlinear relationship between soil moisture and vegetation or topography was found. Also, it is observed by both the TM image and Field investigation that surface soil moisture at mined area is slight lower than at unmined area, especially the variation of loess region is more apparent than sand region. Overall, the difference was not remarkable, so the vegetation did not get worse very much.The groundwater (aquifer thickness, relative and absolute groundwater table) at 32201 mining face was observed from the beginning to the third year after the end of mining. It indicated that the groundwater was disturbed seriously by underground mining. But the vegetation on the 32201 mining face did not get worse as great loss of groundwater, which was explained by the GPR detection of unsaturated zone. The critical groundwater table depth (8m) was found by the analysis of vertical distribution of soil moisture at unsaturated zone. Because the original groundwater table depth before mining was already 30m, which meant that the vegetation did not depend on the groundwater and would not change dramatically, no matter how the groundwater table drop. Additionally, it was the first time to integrate GPR with Mining Subsidence Predicting Theory, then the lateral variation of soil moisture at different deform region was detected. It demonstrated that the compression and stretch deformation due to mining subsidence would change the soil moisture. So, more attention is needed to study the soil characteristics at deformation area in future.Finally, an inverse model of soil moisture and NDVI, and two exponential models of groundwater and NDVI, or soil moisture were developed based on the monitoring results. Furthermore, some recommendations were provided for green-mining at desert mining area.