A novel short‐wall caving zone backfilling technique for controlling mining subsidence

Abstract

Mining‐induced voids are the main circulation pathways for underground fluids such as water and coalbed methane. The collapse of these voids transmits to the ground surface, resulting in subsidence and building collapse. Accordingly, effective and feasible solutions are needed to control surface subsidence. In this study, a novel technique of void filling in the short‐wall caving zone was proposed to better control surface subsidence in thin coal seam mining. The width of the working face plays a key role in the proposed technique. A maximum surface subsidence value was predicted using numerical simulation and physical simulation experiments with different working face widths. The results indicate that the appropriate working face width should be less than 50 m for the studied coal mine. In this example, the surface subsidence coefficient was less than the standard value for initial damage to rural structures. Both advancing speed and productivity of the working face were achieved using the proposed technique because the filling and mining processes were conducted simultaneously on different faces. The results suggest that surface subsidence during thin coal seam mining could be controlled using the proposed technique. This technique can also help mitigate mining‐induced water inrush and gas leakage disasters by filling voids.

The Prediction Model of Super Large Subsidence in High Water Table Coal Mining Areas Covered with Thick Unconsolidated Layer

“…For Surface. According to formula (17), to calculate the surface subsidence factor, we need to know the value of q j , k s , and n. Use formulas ( 18)- (20) to determine q j and formula (16) to calculate n. Generally speaking, k s is variety in different mine areas and does not suffer the effect of dip angle of coal seam and the rock lithology. For convenience in use, the theory lookup table calculated from formula ( 17) is shown in Table 3.…”

“…The values of both are shown in Table 4. According to formula (20), the two should be equal. By searching Table 4, we can see that when k s = 1, the two are basically equal.…”

“…The exploitation of underground coal resources has accelerated the economic development, but at the same time, it has also brought about great economic [1][2][3], environmental, and ecological damage problems [4][5][6][7][8][9][10], such as water accumulation on the subsidence area, cracks on the surface, settlement of residential land, and house damage, etc. For a long time, scholars have been studying and analyzing the mining subsidence under general conditions from the aspects of subsidence law [11][12][13][14], subsidence mechanism [15,16], subsidence prediction [17][18][19], subsidence control method [20,21] and obtained many research results, which have been applied in the field.…”

Study on the movement characteristics of the overlying stratum and surrounding rock control in ultraclose coal seams: A case study

“…The formation of coal seams is affected by various factors, such as geological structure, invasion, and surface subsidence . Therefore, coal seams exist in a variety of geological conditions.…”

“…The formation of coal seams is affected by various factors, such as geological structure, 1,2 invasion, 3,4 and surface subsidence. [5][6][7] Therefore, coal seams exist in a variety of geological conditions. With the increasing intensity of coal mining, coal seams with favorable geological structure and shallow depths are diminishing continuously.…”