Difference in Surface Damage between Deep and Shallow Mining of Underground Coal Resources in China

Abstract

The mining of underground coal resources often results in extensive damage to the ground surface, particularly in China, which has a large amount of coal resources. However, the laws of surface damage caused by the mining of deep and shallow underground coal resources are relatively different. This study analyzes the difference in surface damage induced by deep and shallow mining and its mechanism by field measurement and similar material simulation experiments. Surface damage is mainly manifested in the form of cracks, which can be categorized as permanent and dynamic cracks. Permanent cracks occur above the mining boundary of shallow and deep coal mines. Dynamic cracks (including dynamic stretching cracks and stepped cracks) only appear above the goaf in shallow mining. This disparity is due to the fact that strata movement in deep mining occurs in a “three zones” mode, with the failure height of strata increasing with the mining degree in an “S” shape. However, rock strata movement in shallow mining follows a “two zones” mode, with the failure height of rock strata increasing exponentially with the mining degree. Thus, the rock strata are prone to slide and become unstable in the form of benched rock beams, producing dynamic cracks, such as stepped cracks on the surface. This research improves the existing mining subsidence theory and provides technical support for relevant mines to take targeted treatment measures.

Application of the Time Function Model for Dynamic Deformation Prediction in Mining Areas under Characteristic Constraints

“…By substituting Equation (9) into Equation (7), the subsidence at the moment of peak velocity can be determined as:…”

“…Lian et al [6] used mechanical methods to analyze the mechanism of coal mining damage and studied the laws of discontinuous movement and deformation of overlying rock and surface under different rock-soil ratio conditions. Yan et al [7] analyzed the difference in surface damage induced by deep and shallow mining and its mechanism by field measurement and similar material simulation experiments. Wei et al [8] analyzed the deformation of the old goaf in a coal mine and its influence on the surrounding rock and soil layer.…”

Studying sinkholes of the earth’s surface involving radar satellite interferometry in terms of Zhezkazgan field, Kazakhstan

“…This model allows combining all the parameters in one database that affect the safety of mining operations. It should take into account structural disturbances of the rock mass, which affect negatively the stability [53]- [57]. To build a model of voids, it is necessary to digitize the secondary documents remained in the archive.…”