## 3 Application of 5G+ Big Data in Fully-Mechanized Mining Face with a Super-Large Mining Height
### Roof Control in Fully-Mechanized Mining Face with a Super-Large Mining Height  
The 12,404 fully-mechanized mining face has just commenced initial mining. Currently, we are only able to analyze the conveyor current, mine pressure, and shearer speed during the initial mining stage, and apply the general rules in the initial mining period to other stages. Additionally, throughout the mining process, we continually distill new insights and rules, which can be utilized for further research and application. Initial mining and strong release stage  
In the early stage of mining, the 12,403 fully-mechanized mining face employed water pressure pre-splitting and triangular zone blasting forced caving technology. Two boreholes were arranged for water pressure pre-splitting, and each borehole was fractured into 9 sections. Four blasting holes in the triangle were constructed in the rubber conveyor belt, and five were constructed in the return air gate road. After the working face was put into operation, the roof of the middle goat did not obviously collapse after caving at both ends initially. When advancing to 10-20 m, the roof gradually collapsed and filled the goat. When advancing to 44 m, the initial weighting occurred in the main roof, with the weighting occurring on the 80-105# supports at the tail of the machine, exerting a pressure of 40-50 MPa. Among these, the 90-105# supports experienced higher pressure, and the working face suffered severe spalling. After four consecutive cuts, the spalling weakened. Subsequently, the weighting occurred on the 25-70# supports at the head of the machine, with the local pressure of the working face exceeding 45 MPa, leading to increased spalling of the coal wall. After three consecutive cuts, weighting occurred over a large area on the 25-110# supports at the working face, resulting in severe spalling of the working face. The beam end distance was large, and there was still a beam end distance before and after the advancement was completed. The mine pressure behavior of 50-70# and 90-100# supports was strong, and the coal wall became brittle. The initial weighting ended after advancing 57.4 m.  
According to the analysis of the mine pressure-heat diagram (Figure 11), the current change diagram of the conveyor (Figure 12) and the speed change diagram of the shearer (Figure 13) during the initial mining period of 12,404, at the initial weighting stage, as shown in stage I of Figure 13, i.e., the weighting step is 7.2 m, the persistence length is 4 m, the non-pressure persistence length is 3.2 m, the weighting time is between 11-20, 10:54:56 and 11-21, 02:53:21, corresponding to stage I in Figure 12, there is a period of time when the current is 0, which is analyzed with the operation situation during the production period. During the shutdown and maintenance period, the current at this stage is not analyzed and considered. The rated current of the conveyor is 325 A, which exceeds 85% of the rated current of the conveyor, that is, 276.25 A, and results in overload. Therefore, the conveyor has a crushing risk. In interval A, the maximum current of the conveyor reaches 414.29 A, which is far more than the overload current of the equipment. At the same time, the speed change diagram of the shearer is compared and analyzed. As shown in stage a of Figure 13, in interval \(\alpha\), the speed of the shearer soars, and the maximum value reaches 15 m/min. Compared with the speed of the shearer in the same stage, most of them are below 10 m/min. The speed of some shearers is in the stage of 0, which is the time of shutdown and maintenance without analysis. According to the comparison of the time axis, it is observed that the high-speed stage of the shearer speed is ahead of the overload stage of the conveyor. The reason is that the shearer cuts coal at high speed, more coal blocks are broken down to the conveyor, and even large blocks are crossed between the coal wall and the cable groove to increase the resistance.