## 3 Application of 5G+ Big Data in Fully-Mechanized Mining Face with a Super-Large Mining Height  
Coal has long been an important supporting energy source for national development. The coal industry is facing a shortage of human resources. Currently, \"mechanization of labor\" has been widely adopted. The workers still have high labor intensity when operating coal mining equipment in confined working spaces, and \"automation to reduce manpower\" needs to be further implemented. The intelligent control system of the 12,404 fully-mechanized mining face with a super-large mining height applies \"5G + working face three-dimensional digital twin system + automatic speed control system for three machines + precise positioning technology for the shearer + electro-hydraulic control and attitude monitoring system of support equipped with HarmonyOS + shearer automatic coal cutting system + centralized lubrication for the three machines, centralized lubrication for the shearer, and intelligent spray system + centralized control system for the fully-mechanized mining face\" to create a fully-mechanized mining face with a super-large mining height and build an underground centralized control center. A 4G/5G dual redundant security network communication system has been established for the project. All employees can read the system data at any time, and check the production status of the fully-mechanized mining face, thereby realizing the information sharing and participation of all employees in the management of the intelligent working face. 1. Three-dimensional digital twin system of working surface  
The three-dimensional digital twin system of the working face is a three-dimensional mirrored scene simulation of the fully-mechanized working face, as shown in Figure 7, which integrates process self-optimization, data visualization, and strong human-machine interaction to display the real-time status of the fully-mechanized working face. From the three aspects of data information interaction, physical working face, and digital working face, the on-site fully-mechanized working face is simulated and optimized in terms of process, production workflows, production management, equipment performance, etc., and the \"data-centered production model\" enables equipment interconnection and reproduction of production scenarios, and accurately guides underground production operations. Intelligent mining face monitoring, planned cutting, abnormal area pre-warning, real-time monitoring of shearer and support data, intelligent restoration of shearer and support, real-time monitoring of transportation equipment conditions, and immersive roaming of the working face scene. 2. Automatic speed control system for three machines  
Figure 7: Digital twin monitoring system of fully-mechanized mining face. At present, the automatic speed control system for three machines generally believes that the coal quantity on the conveyor is derived from the coal cut by the shearer. However, in fully-mechanized mining faces with super-large mining heights, particularly in areas with significant mine pressure behavior, the shearer has few cutter holders for its top cutter, and most of the coal blocks on the top of the coal wall fall off. Therefore, the traditional flow estimation method is no longer applicable for fully-mechanized mining faces with a super-large mining heights. In order to accurately estimate the coal quantity on the conveyor, the automatic speed control system for the three machines in such mining faces utilizes laser cross-section scanning based on video recognition. This system can not only assess the coal quantity on the conveyor but also quickly identify when large pieces of the coal wall fall across the conveyor, causing a blockage and resulting in an overload of the conveyor. It can then rapidly take action to prevent the three machines from overloading, thereby enhancing the reliability of the system.