Study On Shape Optimisation Of Boundary Slope In First Mining Area Of Thar Coalfield Block Ⅰ Open-pit Mining

The form of the mine’s slope is a key element to determine its economic efficiency and production safety.Therefore it is important to study how to optimise the final slope shape of the open-pit mine in order to reduce production costs.There are three aquifers within the side slopes in Thar Coalfield Block I Open-pit Mining in Pakistan.Its weak layers are developed and complex.How to determine a safe and economical slope form is an important prerequisite for safe and efficient mining in open-pit mine.The thesis focuses on the optimization of slope shape in Thar Coalfield Block I Open-pit Mining in Pakistan.Based on the analysis of the engineering geological characteristics and the stability influencing factor of slopes,the location of the weak layers within the slope and the physical-mechanical parameters of the pit slope are determined.The potential landslide mode is obtained by analysis and judgment.The cross section shape of stope slope is optimized by the rigid body limit equilibrium method.Using the numerical simulation method,optimized design of slope space shape based on transverse mining internal dump stripping project.The economic benefit analysis of the optimized slope shape is carried out.The results of the study show that the potential landslide pattern of the pit slope is either rotational slide or cut-bedding sliding with the key weak layer as the bottom interface.Using the cross-section shape effect of the slope,the cross-section shape is designed as a convex slope shape with the top of the coal seam roof as the inflection point.The final optimised slope angles for G3 East,G5 South and G5 North are 25°,25° and 23° respectively.Based on the spatial shape effect,the optimized slope angles are 27°,27° and 25° for G3 East,G5 South and G5 North respectively.Determine the tracing distance within the transverse mining internal dump should be controlled within 50 m.The analysis of the two slope optimisation shapes in comparison with the equal horizontal pan straight slope and the original design slope shape shows that the slope angle has been increased while ensuring the safety of the slope.The potential economic benefits of the cross-sectional shape effect and the spatial shape effect are fully highlighted.The paper has 45 figures,19 tables and 53 references.