Disasters such as rock bursts and mine earthquakes became increasingly serious with the increase in mining depth in Erdos Coal Field and became serious problems that restrict high-strength continuous mining of coal mines. In this study, strata movement and energy polling distribution of ultrathick weak-bonding sandstone layers were controlled by the local filling–caving multi-faces coordinated mining technique, which was based on the analysis of subsidence and overlying structural characteristics in the Yingpanhao mining area. Moreover, the influencing factors and the control effect laws were investigated. Surface subsidence and energy polling distribution control effects of different mining modes were compared, which confirmed the superiority of local filling based on the main key stratum. According to the results, the maximum surface subsidence velocity of the first mining face was 1.24 mm/d, which indicates the presence of a logistic functional relationship between the mining degree and subsidence factors. When the mining degree was close to full mining, the practical surface subsidence was smaller than the corresponding logistic functional value. The largest influencing factor for the strata movement control effect of partial filling mining based on the main key stratum was the width of the caving face, followed by the filling ratio, section pillar width, and width of the filling face, successively. With respect to the influencing degree on the energy polling distribution of partial filling mining based on the main key stratum, the order followed as section pillar width > filling ratio > caving working face > width of backfilling working face. Additionally, the comparative analysis from the perspectives of control effect, resource utilization, and cost-effectiveness demonstrated that partial filling mining based on the main key stratum was one of the techniques with high cost-effectiveness in controlling strata movement and relieving rock bursts, mining earthquakes, and subsidence disasters.

This study uses monocular digital photography and a measurement robot (MDP&MR) to monitor the sluice vibration deformation in the gate lift test and in the sluicing test. The photographing scale transformation and time baseline parallax (PST-TBP) method is proposed in the field of monocular digital photography. Results show that the PST-TBP method improves measurement accuracy slightly. Measurement accuracies on the reference plane were 0.62 pixels (0.40 mm), 0.76 pixels (0.49 mm), and 1.10 pixels (0.71 mm) in the X, Z, and comprehensive-directions, respectively. The PST-TBP method overcomes the limitation that the photographing direction must be perpendicular to the sluice plane when monocular digital photography is used to monitor the sluice. MDP&MR proves an effective method in monitoring the sluice vibration deformation as MDP can be used to monitor the trend of the sluice vibration deformation and the MR allows high-accuracy monitoring of the short periodic deformation of the sluice. They have complementary advantages to achieve better results. Thus, MDP&MR can provide a new way to assess sluice health in vibration.

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.

Underground coal mining leads to land subsidence, which, in turn, results in damage to buildings and infrastructure, disturbs the original ecological environment, and hinders the sustainable development of coal mining cities. A reasonable estimation of land subsidence, on the other hand, is the foundation for building protection, land reclamation, and ecological environment reconstruction. However, when we applied the existing land subsidence estimation theory to the deep mining areas of the Ordos coalfield in western China, there was a significant deviation between the estimations and the measurements. To explain such unusual case, we propose using the overburden’s average GSI (Geological Strength Index) value instead of the compressive strength (UCS) of rock specimens for a better representation of the overburden’s overall properties. By using on-site subsidence monitoring results and historical data, we provided evidence which supports that the overburden’s average GSI value has a much greater impact on subsidence rates than the UCS. Subsequently, we investigated the relationship between three typical overburden’s GSI values and the subsidence rates via a calibrated numerical model, revealing the variation patterns of maximum surface subsidence when the overburden’s average GSI value is set at 30, 50, and 75, respectively. Finally, on the basis of the measured and simulated results, we discussed a non-conventional strip mining method for mining subsidence control in the deep mining areas of the Ordos coalfield in western China, and explained why it is possible and what are the significant advantages behind. The proposed methods, findings, and suggestions in this paper are therefore quite helpful for researchers and engineers who wish to estimate and control the mining-induced land subsidence, as well as for those who are particularly interested in the study of environment science related to land subsidence.

While surface movement regularities have been sufficiently understood in the mining practices of eastern China, the case seems to be very different in western China where the super-thick and weak cementation (STWC) overburden exists. To better understand such knowledge, we compared geomining conditions and surface subsidence data for 16 coal mines and developed a carefully calibrated numerical model, with primary concern the relationship between subsidence rate and mining scale. We find that mining under the STWC overburden is characterized by the extremely small subsidence rate compared to the deep mining cases in eastern China, and the unusual subsidence phenomenon should be regional rather than an isolated case. We also find that the critical subsidence basin can be formed only when the goaf length and width both reach about 3.3 h (h is the average mining depth), which is far beyond the conventional understanding. We suggest that the large-scale mining under the STWC overburden carries enormous risks, which require great attention. The reported data, findings, and suggestions in this paper should be quite useful for coal mines with similar geomining conditions, and are also important for ecological protection and sustainable development of western China.

Surface subsidence induced by underground coal mining, together with the associated damage to surface infrastructure and a range of ecological impacts such as hydrological disturbance and vegetation degradation, collectively hampers the sustainable development of coal resource-based cities worldwide. What remains unclear, however, is how discontinuity density influences mining-induced surface subsidence (mining subsidence), which may render conventional analogy-based analysis methods inadequate for interpreting the anomalously low surface subsidence observed in the Ordos coalfield in China. In this study, we demonstrate that the stiffness of the overburden, represented by the uniaxial compressive strength of intact rock ([Formula: see text]), is not a sufficient indicator for subsidence estimation, and the discontinuity density may play a more influential role. To substantiate this claim, a series of UDEC models with varied discontinuity density and rock stiffness were built and calibrated, and the modeling results were compared with practical cases to assess their validity. The results indicate: (1) increasing discontinuity density leads to a systematic shift in the dominant overburden failure mode from intact rock deformation to block sliding, thereby reducing the reliability of [Formula: see text] as an indicator for subsidence estimation; (2) the applicability of [Formula: see text]-based analogy methods is conditional, being reliable primarily when discontinuity densities are comparable; and (3) higher discontinuity density reduces the width-to-depth ratio required for critical mining, which helps to explain the delayed and attenuated subsidence observed in deep coal mining areas of Ordos, China. The study provides useful insights for subsidence prediction and mining design, and contributes to a better understanding of subsidence mechanisms relevant to the sustainable development of coal resource-based cities.