Key technology and equipment of intelligent mining for 1.1 m hard and thin coal:Jurassic coalfield in Northern Shaanxi as an example

In view of the mining problems of the Jurassic coalfield in northern Shaanxi with shallow burial depth, hardness of about f3, average coal thickness of about 1.1 m, narrow working space, high difficulty of high-power equipment arrangement and intelligent implementation, the coal seam occurrence and support technology were researched in depth. The coordinating method, process and complete set of technology for the high energy-to-product ratio space-time coordination of working face equipment and the large drop flexible system at the end of the roadway are proposed. A flexible system model with a large drop at the end is constructed, and the energy-to-product ratio reaches 402, which meets the requirement of a large drop of more than 1.4 m between the roadway and the working face, and realizes safe, efficient and intelligent mining of hard and thin coal seams of 1.1 to 1.3 m. A complete set of intelligent equipment for 1.1-1.3m hard and thin coal seams has been developed. The shearer adopts a semi-suspended body and a full-suspended cutting short body structure. The body height is 759 mm, the installed power is 1 050 kW, and the maximum traction speed is 14.5 m/ min. A high-rigidity anti-dynamic load hydraulic support with a working resistance of 9 000 kN was developed, which adopted an anti-shock large telescopic ratio column, and a high-strength sheet structure. A large capacity, short body, overlapping side discharge scraper conveyor was developed, and the installed power reaches 3×400 kW. The thin coal seam refinement and intelligent related devices have been developed. A thin coal seam intelligent monitoring system suitable for thin coal seam memory cutting, automatic and accurate straightening, intelligent load control, wired and wireless dual-network communication, multi-data integration and linkage, equipment remote fault diagnosis and full life cycle management is developed, and the normalized mining mode with unmanned operation in the working face was realized. By constructing the core technology system for intelligent fully mechanized mining of 1.1-1.3 m hard and thin coal seams, a complete set of technologies and equipment for intelligent fully mechanized mining of 1.1-1.3 m (especially 1.1 m) hard and thin coal seams in northern Shaanxi Jurassic coalfield has been formed. The research results of this paper have been applied in Zhangjiamao Coal Mine and Liangshuijing Coal Mine. The equipment and system run stably and reliably, reaching an annual coal output of 13 Mt.