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In longwall top coal caving (LTCC) mining methods, problems such as large deformations, loss of coal resources, and excavation relay out of balance are often encountered with the increased production in single mining panels. To address these problems, a novel non‐pillar coal mining technology in LTCC was used based on the equilibrium mining theory. This approach could cut off the stress transmission, eliminate the coal pillar, and retain the gob‐side entry. In this technology, the entry is first excavated along the roof of the coal, and then four techniques are applied to control the surrounding rock of the retained entry. The constant resistance and large deformation anchor cable are used to maintain the roof stability. The directional roof split blasting technique is adopted to separate the roof between the entry and gob. The blocking‐gangue support system (BGSS) is used to form the gangue rib lagging the mining panel. The temporary support system is applied to prevent the roadway from being affected by the dynamic pressure and prevented the BGSS from falling. Finally, the field monitoring results indicate that the surrounding rock of retained entry is stabilized at 200 m behind the working face. The deformation of retained entry is within a reasonable range at 180–190 m behind the mining panel. The results provide an important reference for the thick coal seam non‐pillar coal mining technology, specifically using this technology in LTCC panels. [ABSTRACT FROM AUTHOR]

Under the conditions of high ground stress and mining disturbance, the strata breakage that is induced by mining is severe. Thus, it is critical to investigate the structural characteristics of key strata (KS) in deep thick mining. This study introduces an innovative technology, namely, directional blasting fracturing, in which an energy-gathering tube is installed in a borehole and an explosive is detonated to break the roof in a specified direction. A theory of balanced bulk filling is established based on the requirements of developing a voussoir beam structure, which can be used to effectively evaluate the percentage of bulk filling in gob and to determine to which structure the key strata belongs. Based on this theory, two types of novel structural models in the advancing and lateral directions of the longwall face are established and defined for studying the roof fracturing mechanism. Compared with a cantilever structure, Model C can develop a stable voussoir beam structure, limiting the rotation space of the KS and reducing both the peak abutment pressure and the dynamic disturbance time in the advancing of the longwall face. Model E is defined as when the technology of directional blasting fracturing effectively cuts a stress transfer path into the barrier pillar. The peak abutment pressures on the barrier pillar and auxiliary entry are smaller, and the dynamic disturbance time is shorter, which can effectively improve the stability of the auxiliary entry. The key parameters of directional blasting fracturing are designed and constructed, and they include the roof fracturing height, angle, and charge structure. The field application performance of this innovative technology at the longwall face of 3−1101 in Hongqinghe coal mine was evaluated by analyzing the chock pressure stress, the pillar pressure stress, and the deformation of the auxiliary entry during mining, which lays a foundation for the application of this technology in coal mines in China. [ABSTRACT FROM AUTHOR]