Study On The Formation And Recovery Method Of Horizontal Pillars In Maoping Lead-zinc Mine

In recent years,mechanized broader stope area,continuous layoout without pillars and double middle even more middle stoping mining model is widely used along with many horizontal cut and filling stopping mining method(Downward/upward)use the whole section excavation which along the ore body level.Horizontal pillar inevitable dynamic formation in the process of double middle or more-middle stopping mining model and filling roofs are unable.Therefore,determining the critical thickness of horizontal pillar accurately and exploiting the horizontal pillar resources in the maximum degree are extremely significance to extending the length of service and make full use of limited mineral resources.This paper takes Maoping Lead-zinc Mine as the background,obtained the determine model of horizontal pillar critical thickness by adopting theoretical analysis method and numerical calculation method.At the same time,analyzing the effects of different filling route section on the formation and stability of horizontal pillar,reaching a conclusion that hexagonal filling route can delay the formation time of horizontal pillar.The main research contents and conclusions are as follows:1?According to the engineering characteristics of horizontal pillar.Based on Volasov thick plate theory,the determine model of horizontal pillar critical thickness was obtained,obtained a relationship between horizontal pillar critical thickness and ore body thickness and ore body mechanical parameters,providing a reliable basis for the mining timely and accurately decide horizontal pillar critical thickness.2?Using numerical analyze method,combining actual production conditions of Maoping Lead-zinc Mine,develop the numerical value models,comparing the formation and destruction of horizontal pillar under different conditions in rectangular filling route and hexagonal filling route.Obtained that using rectangular filling route and double middle mine,caused 20m thickness ore body can't stopping;using downward hexagonal drift cut-and-filling stopping mining method can ensure the stability in the process of horizontal pillar mining,exploit the horizontal pillar resources in the maximum degree.3?Analysis of the mining process of the different unsupported roof distance with hexagonal filling route by using numerical simulation,obtained that it can ensure the safety and reduce the filling cost using lm unsupported roof distance of rectangular filling route.4?The research results were applied to the production practice of 720 middle segment of Maoping Lead-zinc Mine.The mine statistics showed that,91815.7t ore was stopped,stope production capacity is 380t/d,recovery rate is 94%.And collapses?roof falling and rock-fall have not happened in the process of exploiting the horizontal pillar resources.Those research results of paper further enrich the connotation about the research of horizontal pillar,has great theoretical significance and engineering application value.On one hand,providing theoretical basis for the mining decide horizontal pillar critical thickness;On the other hand,using downward hexagonal drift cut-and-filling stopping mining method not only can ensure safety,continue and stability,but also increase ore recovery rate and mine economic effect,which are provide technique reference for mine safety recovery horizontal pillar.