Objective 3D twin models for complex gangue-bearing coal seams are designed to achieve an information-based description of physical coal seams and faithfully map their virtual forms. Twin modelling is identified as a prerequisite for exploring the efficient cutting of intelligent shearers while providing an effective data guarantee for achieving unmanned mining.

Methods Using data on samples from the mining face of coal seam 17 in the Yanzhou mining area, Shandong Province, this study proposed a methodology that integrates more information about the geological structural conditions of coal seams. Specifically, digital twining of iron sulfide nodules was performed using the irregular particle modeling technology, the coal-rock particle filling technology for coals was optimized, and the surface roughness of coal-rock particles was simulated using a user-defined contact model. Based on the constructed initial static 3D twin model for a coal seam, this study compiled the application plugin for coal seams and added new attributes to coal-rock particles and structures according to geological characteristics, thus correcting the twin model structure. The feasibility of the twin model was verified using the cutting experiment with a shearer.

Results and Conclusions  The results indicate that the initial static 3D twin model for the coal-seam mining face was constructed by adding iron sulfide nodules, faults, and coal seam roofs and floors. The dynamic 3D twin model for a complex gangue-bearing coal seam was established, enabling the correction and replacement of the particle set. The cutting experiment with a shearer demonstrates the similarity of physical properties between the modeled coal seam and actual coals and rocks, yielding minor errors in drum load during coal-rock cutting between the 3D twin model for a complex gangue-bearing coal seam and actual coals and rocks. The 3D twin model was applied to the bidirectional coupling test of coal-rock cutting, demonstrating that the optimized, reconstructed 3D twin model for coal-seam mining face faithfully reflected the coal seam morphology of the mining face. The dynamic 3D twin model for a complex gangue-bearing coal seam, allowing for the correction and replacement of the particle set, can reflect the information about various geological structures in actual mining face more accurately and rapidly, enabling more effective acquisition of coal-rock cutting information.