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In order to efficiently and safely mine the end-slope pressure coal left after the open-pit mining, find out the slope deformation and stress redistribution characteristics caused by the group roadway effect under the end-slope mining, and ensure the slope stability and safety, taking an open-pit mine as an engineering background, through analyzing the stress distribution characteristics of the end-slope mining pillar, the reasonable design parameters of the coal pillar for end slope mining are determined. The Midas GTS NX finite element numerical simulation is used to study the stress and deformation characteristics of the slope caused by end-slope mining and verify the slope stability. Furthermore, through the optimization of roadway layout to improve the recovery rate. The results show that: for the mining of thick coal seam with end-slope, the strength, size of coal pillar and the layout of mining roadway are the main control factors affecting the slope stability. The overall slope safety factors of single row and double row roadway layout are 1.21 and 1.14 respectively, and the slope safety is reduced. However, the overall slope can still meet the requirements of safety factor, and the recovery rate of end-slope coal will be increased by 5%, which can effectively recover the amount of end-slope overburden resources.

Carbon-enhanced TiO2/graphene composite photocatalyst was prepared by two-step method. First, anatase TiO2 nanocrystals with amorphous carbon layer (C-TiO2 nanocrystals) were obtained in acetone solvothermal condition. Then, graphene was coated by reduction from graphite oxide and simultaneously combined with the C-TiO2 nanocrystals in a one pot solvothemal reaction. The structure, morphology, optical and photocatalytic properties of the samples were investigated. This carbon-enhanced TiO2/graphene shows high visible light photosensitivity and favorable photocatalytic activity toward methyl orange. [ABSTRACT FROM AUTHOR]