Coal is one of the fundamental fossil energy supporting the world’s economy. The synergistic development between efficient coal mining and ecological environment protection is the inevitable requirement for the preservation of global harmony. As the world’s largest coal producer, China has conducted a strategic shift from east to west in terms of the exploitation of its energy resources, posing a serious threat to the fragile ecological environment of the western region. In particular, the surface subsidence caused by coal mining is the root of the ecological deteriotation and the destruction of ground structures. However, it is difficult to reveal the law of large-scale surface subsidence in western mining areas merely by conventional measurement methods such as leveling, on account of the high intensity of coal seam mining, the weakness of the lithology of overlying rock and the large thickness of wind-blown sand strata. In view of this, small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) technology was used in this study to obtain the time series of surface vertical displacement during the whole mining process of the 2401 working face in the Yingpanhao coal mine, Inner Mongolia. Based on the deformation data, the dynamic evolution characteristics of surface subsidence under high intensity mining in the western mining area were analyzed exhaustively. It was found that the surface subsidence is characterized by an extensive coverage range (48.52 km²) with minimal ground settlement (250 mm) in the study area. Meanwhile, the boundary shape of the subsidence basin followed a “circular-parallelogram-trapezoid” changeable process and the coverage area of the basin experienced three stages: a linear increasing period, a temporary stagnation period, and a re-expansion period. Furthermore, there existed an abnormal uplift phenomenon on the east side of the open-off cut in the 2401 working face. Combined with the structure of overlying strata, this paper carried out a preliminary analysis on the reasons of the abovementioned phenomenon. The research results are of vital realistic significance for ground buildings and ecological environmental protection in the aeolian sand mining area in Western China.

While universal discrete element code (UDEC) is widely used for understanding the mechanism of large-scale strata movement and the effects of mining subsidence on the environment, the fundamental knowledge of how to set vertical joint spacing (VJS) in UDEC is still not fully understood. To address the knowledge gap, we first present a novel VJS calculation method, then conduct UDEC experiments, and finally compare the predictions of UDEC models with field subsidence observation. The results suggest the following: (1) when compared to the conventional VJS setting (1× to 3× bed thickness), the maximum surface subsidence (MSS) prediction via UDEC models based on our proposed VJS setting method is closer to field observation; (2) a smaller but varying VJS setting can also have the effect of a larger VJS setting; and (3) with the increase in VJS, MSS first drops, then rises, and reaches the minimum when VJS is set at approximately 7× bed thickness. This paper provides an explanation of the VJS setting in UDEC and establishes a bridge between the KS theory and VJS, which is helpful for the sustainable development of such an UDEC modeling strategy and for a better understanding of the influences of mining subsidence on the environment in mining-affected areas.

With increases in the mining depth and area in the Ordos coal field, the failure law of the super thick sandstone in the Zhidan group leads to frequent disasters, such as rock bursts and mine earthquakes, which have become a significant issue, restricting large-scale continuous mining. To adequately understand the movement mechanism of the super-thick and weakly cemented overburden, and to promote the large-scale mining of the coal resources under it, this study analyzes the physical and mechanical properties, along with the microstructural characteristics, of the weakly cemented overburden of the Yingpanhao Coal Mine through mechanics tests, scanning electron microscope tests (SEM) and hydrolysis experiments. A two-dimensional discrete element model of the survey region is then built to explore the temporal and spatial evolution laws of the overburden failure. The results show that, even though poorly cemented strata such as the Cretaceous Zhidan group sandstone and the Zhiluo group sandstone are weak in lithology, their unique mineral composition and microstructural characteristics give them a greater rigidity when their thickness reaches a certain value. The surface subsidence exhibits a sudden increase, and the dynamic disaster range of the overlying strata is wide when deep multi-face mining was carried out under the super-thick and weakly cemented overburden. The temporal and spatial evolution laws of the strata subsidence and influence boundary are closely related to their depth, and their relationships evolve into the Boltzmann function and Boltzmann–parabolic function, respectively. The failure mode of the super-thick and weakly cemented overburden is ‘beam–arch shell–half arch shell’, and the failure boundary exhibits arch fractures.

The Stability analysis of datum points is a fundamental procedure to verify the monitoring results of leveling settlement. Traditional methods tend to be the employment of repeated monitoring or the increase in measurement points under the same monitoring technique, which are costly and complicated in data processing, making them difficult to be applied in common ground subsidence monitoring scenarios. In view of this, inspired by the idea of external validation, this paper proposes an evaluation method of the stability of datum points in leveling Observation based on Small Baseline Subset InSAR (SBAS-InSAR) technology. Firstly, the paper indicates that differences of subsidence measured by SBAS-InSAR and ground leveling of the same location respectively within close proximity are primarily composed of error caused by unconformity of the position, observation time and measurement method error as well as the displacement of datum points. Based on that, the formulas of calculating errors of unconformity of observation time and the displacement of datum points are derived separately. Afterwards, taking the monitoring of surface subsidence caused by the mining of two working faces in Yingpanhao Coal Mine located in northern Ordos Basin, as practical applications, the feasibility of the method proposed in the paper is verified. And the scope of application of the proposed method is also suggested. This study provides an efficient and economical solution for evaluating the stability of datum points in leveling settlement monitoring, promoting the joint combination of SBAS-InSAR technology and traditional leveling when applied to surface subsidence monitoring.

The deep mining of coal seams in the central Ordos Basin, a critical arid region of western China, is governed by the unique mechanical behavior of ultra-thick, weakly cemented sandstones of the Cretaceous Zhidan Group, which challenge classical overburden control theories. To elucidate the deformation mechanisms of this special overburden and assess its implications for groundwater protection, this study integrates physical similarity simulation, laboratory rock-mechanical testing, microstructural analysis, and distinct-element numerical modeling (UDEC). A 1:500 similarity model simulated the stratigraphic sequence and mining progression. Results reveal that during single-panel extraction, the main roof initiates deformation at a 150 m face advance, with subsidence reaching 5.55 m at a 300 m mining width. Under multi-panel continuous mining, the high-position weakly cemented sandstones exhibit large-scale coordinated bending and plastic flow, forming a distinctive “subsidence–rotation” deformation pattern that propagates upward. Triaxial tests confirm the rock’s low strength and high confining-pressure sensitivity, with peak strength ranging from 27.8 to 71.1 MPa, cohesion of 6.7 MPa, and an internal friction angle of 38.7°. Failure modes transition from tensile splitting at low confinement to shear and plastic flow at higher pressures. Microstructural analyses (SEM/EDS) identify well-rounded quartz grains, extensive intergranular pores, and weak calcite–feldspar cements, explaining the observed high deformability and low bearing capacity. UDEC simulations of multi-panel mining captured progressive horizontal separation, stress redistribution, and composite tensile–shear failure. The water-conducting fracture zone (WCFZ) is shown to develop upward to the base of the Jurassic Anding Formation, with a maximum height of 186 m when the width-to-depth ratio exceeds 1.5. These findings characterize the deformation features of weakly cemented overburden and establish a mechanical basis for predicting the WCFZ, providing critical insights for overburden management and groundwater resource protection in deep coal mining under arid conditions.

Safe and efficient coal mining faces a global challenge in predicting sudden surface subsidence whose mechanisms remain unclear. This study, centered on deep coal seams in China’s Ordos Basin, examines the risk of abrupt subsidence controlled by high-positioned, ultra-thick, and weakly cemented key strata. We adopt an integrated “observation–experiment–model” paradigm. First, we construct a spatial decoupling model to analyze errors in 1D SBAS-InSAR monitoring, leading to a refined 2D method that reduces the three-dimensional monitoring error from 50 mm to under 20 mm. Based on this, the subsidence basin’s boundary angles are accurately determined as 52.3°–58.6° (strike) and 44.3°–48.2° (dip). Second, a large-scale physical simulation experiment visualizes the complete process of overburden failure up to the breaking of high-level key strata. Finally, by coupling remote sensing observations with experimental phenomena, a theoretical model is built to quantify the mechanical behavior of key strata, revealing the critical width-to-depth ratios for the rupture of the Yan’an Formation (0.21–0.27), Zhiluo Formation (0.53–0.82), and Zhidan Group (1.22–1.34). The research not only delineates surface subsidence morphology under special geological conditions but also answers the core questions of why subsidence occurs and when mutation may happen, thereby laying a theoretical foundation for a comprehensive early-warning model for mining areas worldwide.