Research On Mining Technique Of Multi-function Spiral Drilling In Southern End Of Haizhou Open-pit Mine

As to resource depletion,the Liaoning Haizhou open-pit mine was closed in 2005.Leaving behind a man-made pit that was about 4 km long,2 km wide and 350 m deep in the city center.Due to continous spontaneous combustion of exposed coal seam in southern end slope,the huge cost of south slope end building stage was collapsed and formed a high angle ramp.The Haizhou south slope spontaneous combustion seriously damaged the image of the city,threated public safety and contaminated environment.Based on the high and steep Haizhou open-pit south slope,study of the auger drilling-filling method extract the unused coal resources in the south end replace incombustible filling instead.To some extent,the problem of coal spontaneous combustion is restrained.According to the analysis of the stratum lithology of the southern slope,It is concluded that the south slope landslide model is circle sliding.Based on harnessing project of cutting south slope,designing the auger dilling-filling project including arrangement bench of drilling sequence,auger drilling-filling technology,guniting and anchor net to seal exposure coal.Study the best proportioning of filling stuff,select the best final proportioning satisfied engineering require.The filling material ratio which include cement,coal ash,gangue,water is 1,1.25,2.75,3.5.Accord to harnessing project of cutting south slope,using the method of two-dimensional rigid limit equilibrium to pick out the low coefficient district S1.Build three-dimension numerical simulation of the S1.The failure rule and stability coefficient under two kinds of circumstance ranging coal pillar are analyzed.Evently,by comprehensive comparation chose the project 3th is the optimal project which coal pillar width 0.8 m.