Analysis of land damage degree considering terrain factors in coal mining area with high groundwater

Abstract

Land damage resulting from mining activities, especially precious farmland, is an increasingly hot topic, and damaged land should be properly reused to meet human demand through land reclamation. Accurate estimation of land damage degree is of great importance in the reuse planning of damaged land resources. Generally, it is inaccurately analysis without considering original terrain factors. This paper presents more considerable estimation of land damage degree under the mine disturbance in consideration of terrain factors, and improves the practical workflow to achieve more accurate estimation result. An underground coal mining area with high groundwater level in Shandong Province is taken as an example, and the following measurements are implemented: 1)predicts the dynamic subsidence process of the ground surface according to underground mining plan and geological information collected from the coal company; 2) visualizes mining subsidence with the original terrain by using GIS (geographic information system) software; and 3) estimation standard of land damage degree is established, and then it estimates and analyses the results whether considers terrain factors or not, respectively. The study shows that map spot shape of damaged land tends to be more irregular in consideration of terrain factors as the continuous coal mining, which is more reliable and authentic; considering the terrain factors does not change the increasing trend of three kinds of land damage degree area, but change the speed of them. Besides, the ratio of light land damage degree increases steadily, the ratio of middle land damage degree reduces sharply, and the ratio of severe land damage degree decreases slightly. The light degree of damaged land increases from 4.49% in Stage 1 to 14.41% in Stage 4, the middle degree of it drops from 5.17% in Stage 1 to 11.39% in Stage 4, and the severe degree of it changes no more than about 3%. It means that authentic situation is less terrible than general prediction without considering terrain factors. More land resources would not revolute to subsided water area, and less earthworks and money would be invested to reuse the damaged farmland in the eastern China. This study is very useful for practical project with more accurately quantizing the earthwork, and gives a better guidance for land reuse planning and design to avoid unreasonable investment budget.