Application of Roadway Backfill Mining in Water-Conservation Coal Mining: A Case Study in Northern Shaanxi, China

Abstract

The mining induced subsidence and strata deformation are likely to affect the stability of the aquiclude, resulting in loss of water resources in the mining area. In order to reduce the disturbance of coal mining to the overlying strata and to preserve the water resources in the coal mining area, the roadway backfill mining (RBM) method was trialed in Yuyang coal mine in Northern Shaanxi, China. Based on pressure arch theory and ultimate strength theory, a mechanical model was developed to analyze the stability of coal pillars. Then the maximum number of vacant roadways between the mining face and the backfilling face was determined according to the stability of coal pillar and filling body. The method to calculate aquiclude subsidence and deformation was also proposed. Furthermore, as indicated by FLAC3D numerical simulations, the maximum tensile stress subjected by the aquiclude was 0.14 MPa, which is smaller than its tensile strength; the horizontal deformation was 0.24 mm/m, which is also smaller than the critical deformation of failure. Field monitoring data demonstrated a maximum of 2.76 m groundwater level drop in the mining area after mining. The groundwater level was determined to be 4.45~10.83 m below surface, ensuring the normal growth of surface vegetation and realizing the water-conservation coal mining (WCCM).

Constitutive Model of Solid Backfill Materials and Numerical Simulation of Overburden Movement and Deformation in Backfill Mining

“…e accumulation of coal gangues has caused a series of environmental problems [1][2][3], such as land occupation, water pollution, and air pollution after spontaneous combustion [4][5][6][7]. In addition, coal mining can also cause the fracture of key strata [8][9][10][11], resulting in the loss of groundwater resources [12][13][14] and surface subsidence [15,16]. Solid backfill mining is an environmental coal mining technology, in which coal gangue is used as the main filling body to replace the underground coal resources [17,18].…”

Study on Damage Model and Damage Evolution Characteristics of Backfill with Prefabricated Fracture under Seepage‐Stress Coupling

“…Backfill coal mining technology is an effective method to improve the utilization of coal resources and control surface subsidence. It has been widely used in China and has become one of the main means of green coal mining [1][2][3][4][5][6][7][8]. e stability of the backfill is an important factor to prevent the instability of the goaf and the subsidence of the ground surface [9,10].…”

Characteristics of Roof Ground Subsidence While Applying a Continuous Excavation Continuous Backfill Method in Longwall Mining

“…Through studying the damage law of overlying strata in roadway backfill mining, Sun Q et al [38] found that the filling body could successfully support the overlying load, and the strata remains stable after mining. Yu YH et al [39] analyzed the stability of coal pillars in roadway backfill mining, and proposed subsidence equations of every stratum in mining. The above-mentioned various coal mining and backfilling methods are similar to the CECB method in the panel plan and mining and backfilling sequences.…”