Study On The Soil Rock Composite Slope With Fault In The First Mining Area Of Wulantuga Open-pit Mine

Final slope form is the core issue that affects the production safety and economic rational coal resource in the open pit-mine.There is a normal fault FGe2 which direction is closely to the direction of slope in the west slope of the first mining area of Wulantuga open-pit mine.The second mining area dump is located on the west slope,partially covered FGe2 fault.6#coal seam,laying on upper wall is the main coal seam,which made 2.37Mt coal in the dump and the west slope in totally.And the final slope deformation failure mechanism is more complex because of the fault.In order to get how to solve the mine pressure in an economical and reasonable way,on the basis of the slope engineering geology investigation and theoretical analysis,adopting the rigid body limit equilibrium and numerical simulation method,this paper researched the stability variation of composite slope which is consisted of stope and stope-dump by setting different length of coal pillar in upper wall.Based on stability analysis,this paper determined the shape of the final slope after making economic comparison.The results show that:slope stability decreased significantly because of the fault,but the different relative positions of fault and slope make small difference in the stope slope stability;the composite slope stability decreases previously and increases subsequently as the setting length of coal pillar increases.The composite slope stability is in the worst situation when the setting pillar length is 90m.The influence made by the fault to the composite slope stability visibly diminishes when the setting coal pillar length beyond 120m.And the fault affect disappears when the setting coal pillar length beyond 150m.Considering the slope stability and the problem to make use of the coal resource in an economical and reasonable way,the final slope form should be 135m long coal pillar,30 degrees slope angle and 50m long safe distance.