Study On The Stability Of West End-Slope And Mining Scheme Of Steep Slope In Hequ Open-Pit Coal Mine

In the traditional open-pit mining process,due to factors such as safety and process constraints,the angle of the end of the open-pit mine is often small,which leads to the phenomenon of the end-gang pressing coal,resulting in serious waste.With the continuous development of open-pit mining technology and the mature and steep mining scheme has been put forward and applied to the open pit mine production practice,which has greatly improved the economic benefits of the mine.Therefore,this paper analyzes the problem of coal pressing at the west end of the first mining area of Hequ Open-pit Coal Mine,and puts forward the corresponding mining plan of the steep side,which has certain engineering practical significance.This paper firstly analyzes the geological conditions of the open-pit coal mine in the river area,and determines the stratum that affects the overburden of the slope in the mining area,the basic factors that affect the stability of the slope and the mechanical parameters of rock mass.Aiming at the mining status of the western end of the first mining area,two typical sections are selected,and one typical section is selected at the boundary position of the first mining area in combination with the final map,and the stability of the slope is analyzed based on the limit equilibrium method and the finite element strength reduction method.,it is found that under the current mining situation,the slopes of the western end are in a stable state,and the slope shape is obviously convex slope shape.The blasting vibration coefficient is 0.03,and the influence of blasting vibration on the slope stability is analyzed,and it is found that blasting vibration has little effect on the stability of the west end of the slope.Starting from the two forms of straight slope and convex slope,the angle and structure of the west end are optimized.Under the state of straight slope,the maximum slope angles that can be realized for the three sections are 39°,33° and 43°.Taking the slope angle determined by the straight slope angle as a reference,and the upper soft rock as the boundary line,the stability states of different combined slope angles under the condition of convex slope were explored respectively,and the optimal slopes of the three sections were determined.The stability angles,the upper slope angles are 28°,27° and 34°,and the lower slope angles are 43°,40° and 47°,which correspond to the overall slope angles of 36°,33° and 41°.Based on the numerical simulation results and the mining theory of the steep gang,the parameters of the transportation flat plate and the clearing and maintenance flat plate are determined for the west end gang,and two feasible schemes are proposed,and a threedimensional slope geological model is established and the coefficient is 1.2.Considering the construction process may affect the operation of the West end-slope transportation system,it is proposed to replace the West end-slope transportation system by arranging double bridges in the stope.Combined with the consideration of engineering volume and economy,the convex structure slope plan is finally used to implement steep mining,which can achieve an average annual coal mining of 376,000 tons and an average annual economic benefit of 16.0 million yuan.