Under similar geological conditions, the support height of the hydraulic support for the mining face of the soft coal seam is high. Compared to stratified mining and top coal mining, the probability of the accident of the surrounding rock is likely to increase. The size of theraymond mill plus the large-scale mining hydraulic support is large and the quality is high. The difficulty of disposal accidents is also affected by Will increase. The boron, chromium and other elements dissolved in high-temperature austenite of high boron cast steel and the uniformity of carbon, manganese, chromium and other elements in austenite are poor, and the effect of quenching temperature on the microstructure of high boron cast steel. When the quenching temperature is lower than 950°C, the overall hardenability of austenite is low, and the existence of local pearlite and a small amount of ferrite, pearlite and ferrite in the quenched structure leads to a low hardness of the high boron cast steel. As the quenching temperature increases, the amount of dissolved boron, chromium, and manganese in the high-temperature austenite increases, and the uniformity of the distribution of carbon, manganese, and chromium in the austenite increases, and the austenite hardenability increases. With continuous improvement, the ferrite disappears in the quenched structure, pearlite decreases, and the hardness increases. The pearlite has completely disappeared, quenching temperature 1000 ° C. The quenched structure has been completely transformed into a high hardness martensite structure. The boride has good stability. X-ray diffraction analysis shows that it does not decompose at high temperature, still Fe2B, C. In addition, with the increase of quenching temperature, the boride changes from a continuous network to an isolated distribution, which is beneficial to high boron content. Increased toughness of cast steel. The overlying strata structure has undergone major changes. The soft coal seam has a high mining height compared with ordinary mining height. If the traditional theory and crushing equipment method are used to study the surrounding rock control problems in soft coal seams with high mining height, it is not in line with the actual theoretical research on the overlying strata structure of ordinary mining heights, and most of them are focused on the stope. In the “small structure”, for the high mining height of soft coal seams, the problem of surrounding rock control should be studied from the larger range of overlying strata in the stope in order to understand the overburden strata in the soft coal seam with high mining height. Structure & rdquo; Problems. The current research results of crushing equipment cannot objectively and effectively guide the practice of soft coal seam mining with high mining height. Therefore, further research is needed on the theory of wall rock control in soft coal seam with high mining height.