Adit-strip extraction technology and numerical simulation analysis in open pit coal mine

摘要

A great deal of coal will be left under the final end-walls in Chinese open pit mines because of low slope angle in shovel-truck mining technology system and large mining depth.In the traditional surface mining system,the coal under the end-walls will be buried by the inner dumping site,and the coal resources are normally discarded.Considering these situations,this paper describes the adit-strip mining system in order to recover the residual coal based on the geological conditions of coal seams at Chinese open pit coal mines.The outcome shows that coal pillar width will be larger with the increase of mining openings width.However,the coal recovery ration can be improved.To improve the recovery ratio,we should increase the mining width as much as possible when the conditions permit.According to the theoretical and numerical simulation results,the optimal mining width should be 40 m and the pillar width is 17 m in the studied coal mine.Also,at least 30 m boundary pillar has to be left to avoid end-wall slope failure.