With the rise of coal mine underground reservoir engineering in the Shendong Mining Area, the space time dynamic evolution prediction of storage coefficient is becoming one of the critical technical problems for long-term reservoir operation. This coefficient directly determines the storage capacity and the comprehensive benefits of the operation of a coal mine underground reservoir. To this end, the proposed underground reservoir in Daliuta coal mine (No. 22616 working face) is selected in this study for the development and application of an experimental device to measure the storage coefficient. Rock and coal fragments from similar materials are prepared, which are filled and loaded according to the caving rock nature as well as the lumpiness and accumulation mode characteristics pertaining to No. 22616 working face. Subsequently, the measured storage coefficient under circulating water injection conditions revealed a four-dimensional spatial and temporal pattern. It followed the law of storage coefficient under joint interaction of water-rock and stress. The results showed that, prior to the experiment, rock and coal fragments made from similar materials had good water resistance when the paraffin content was set at 8%. The three stress zones were defined based on a theoretical analysis, which were applied on the corresponding loads. During the experiments, significant regional differences were found in the top surface with persisting subsidence of each stress loading zone. Hence, compared with its initial state, the maximum subsidence in the stress stability zone, the stress recovery zone, and the low-stress zone was 7.89, 5.8, and 1.83 mm, respectively. While the storage capacity and the storage coefficient gradually decreased, the former ranged from 0.2429 to 0.2397 m3, and the latter ranged from 0.270 to 0.266. The experimental results are verified by drainage engineering tests in the Shendong Mining Area. In essence, the storage coefficient had remarkable spatial distribution characteristics and a time-varying effect. In space, the storage coefficient increased with height along the vertical direction of the coal mine underground reservoir. However, it decreased with the distance from the boundary of the dam body in the horizontal direction. With time, the storage coefficient decreased dynamically. This study provides a new way of predicting the storage coefficient of a coal mine underground reservoir.

Shaft steelwork is a component of critical infrastructure in underground mines. It connects the mining areas to the surface and enables the transport of personnel, equipment, and raw materials. Its failure or malfunction poses a threat to people and causes economic losses. Shaft steelwork is an exceptional engineering structure exposed to dynamic loads from large masses moving at high speeds and is subject to intensive deterioration resulting from corrosion and geological or mining-induced deformations. These issues cause shaft steelwork to be subject to high structural safety requirements, design oversizing, demanding maintenance procedures, and costly replacement of corroded members. The importance and unique working conditions of shaft steelwork create practical design and maintenance problems that are of interest to engineers and scientists. This paper reviews publications on the structural safety of rigid shaft steelwork and summarises the range of research from the detection of guide rail failures through the assessment of load effects and guide resistance, to the evaluation of structural reliability. The effects of guide rail failures on guiding forces, models of the conveyance-steelwork interaction, the load-carrying capacity of shaft steelwork under advanced corrosion, and the probabilistic assessment of structural reliability are presented. Significant advances in understanding the mechanical behaviour of shaft steelwork and assessing its properties have been reported. This review summarises the current state of research on shaft steelwork structural safety and highlights key future development directions.