## 3 Application of 5G+ Big Data in Fully-Mechanized Mining Face with a Super-Large Mining Height
In the centralized control interface of the three machines, adjustments can be made to the speed control interval, speed control range, and speed of the triangular coal conveyor at the head and tail of the shearer based on different geological and mining conditions, and the aforementioned logic enables stepsless speed regulation. When the roof leaks and large pieces of coal and gangue fall onto the conveyor, the load on the conveyor will increase, causing increases in the traction currents of the three machines. At this time, the speed can be turned up to accelerate the running of the conveyor, thus preventing the accumulation of large pieces. The automatic speed control system for the three machines in the fully-mechanized mining face with a super-large mining face can respond to various complex working conditions, reduce labor intensity, standardize the management of electromechanical equipment, and minimize equipment wear. 3. Precise positioning technology for the shearer  
The shearer encoder is employed to position the shearer. The position of the shearer encoder can be directly read by the mine pressure control system to guide the support following the shearer, allowing for accurate positioning of the shearer without being affected by equipment and geological conditions. Reading the position of the shearer encoder directly through the mine pressure control system is an important breakthrough in support following the shearer at the automated working face of medium and thick coal seams. With this technology, the automated coal cutting and support following the shearer are no longer affected by the working face floor, the shearer position shifting, or automated unexpected stops. The use of the shearer encoder to position the shearer is an important supplement to the use of infrared technology to position the shearer, filling a gap in domestic technology, preventing shearer misalignment due to infrared sensor system failures, and improving the automation rate. The optional installation of infrared sensors in the automated working face saves production costs, reduces maintenance personnel, and saves labor costs. 4. Electro-hydraulic control and attitude monitoring system of support equipped with HarmonyOS  
The electro-hydraulic control and attitude monitoring system of the support equipped with HarmonyOS can achieve functions such as precise personnel positioning, information interaction, and support control. It can perform self-diagnosis of faults and execute self-regulation actions when the equipment is damaged. Combined with the precise positioning technology of the shearer, centralized follow-up automation can be achieved. In risk conditions such as end triangular coal bevel cutting and middle bevel cutting, it supports remote control, wireless remote control, automatic pressure replenishment, and backwashing, ensuring production safety in real time [40]. In normal production, important data such as column pressure, displacement stroke, and position and direction of the shearer are monitored in real time and transmitted to the three-dimensional digital twin system of the working face. In order to facilitate safe production in emergency situations, the sound and light alarm, emergency stop, locking, status display reminder, and other functions of the electro-hydraulic control system can be manually operated, and the parameters can be adjusted and set online [41]. The ZE07-05E Ethernet electro-hydraulic control system is stable, reliable, and powerful, as shown in Figure 8.  
With the help of HarmonyOS, technologies such as high-precision personnel positioning, video monitoring systems, and mining equipment Internet of Things have been implemented. The video monitoring system for the 12,404 fully-mechanized mining face has been established as shown in Figure 9, which displays the environment and equipment information of the intelligent working face in all aspects.