1560 Figure 7 Underground kilometer-scale directional drilling equipment 3.5 Face Roof Disaster Early Warning Platform A platform with algorithms for automatic identification of support working conditions, prediction of weighting intensity and span was developed. It enables timely understanding of face strata pressure behavior and evaluation of support efficiency and fracturing effectiveness. Figure 8 Interface of coal mine face roof disaster early warning platform 4. ENGINEERING TEST OF HARD ROOF HYDRAULIC FRACTURING FOR STRONG STRATA PRESSURE CONTROL IN 10M LARGE MINING HEIGHT FACE 4.1 Roof Hydraulic Fracturing Borehole Layout Plan The 10m ultra-large mining height face is 300 m long and 5977 m in strike length. Roof fracturing was designed across the entire width and length of the face. The fracturing was divided into two main areas: the initial mining and caving zone (chainage 5600–5977 m, i.e., the setup room entry) and the other areas (chainage 0–5600 m). Initial Mining and Caving Zone. To achieve seam weakening and sufficient pre-fracturing weakening of the roof, three types of fracturing boreholes were designed for initial caving based on different drilling horizons and methods. 1) Cross-seam conventional boreholes: Drilled from the setup room entry, with inclinations of 18°, 35°, and 62° for Type A, B, and C boreholes respectively. Type C boreholes overlapped with Type A locations. Bit diameter was 85 mm, with spacing of 30 m. 2) In-seam conventional boreholes: Drilled from the setup room entry, three boreholes E1–E3 were constructed with horizontal spacing of 60 m, inclination of 1°, and horizon height of 4 m. 3) Roof directional boreholes: Eleven boreholes were drilled from chainage 5600 m in the auxiliary haulage roadway, with a borehole diameter of 120 mm, targeting fracturing horizons at 13 m, 30 m, and 80 m. Two boreholes along the face length direction were arranged from chainage 5900 m in the return airway,
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