Research On The Optimization Of Thin Seam Coal Auger Mining Method And Stope Stability

There are several methods for thin seam mining, auger mining is one ofthem. This mining method has been used in some mines in our country, hasachieved some results. It can reduce the thickness of coal seam mining limit,minimum0.4m can be mined. Because the workers do not enter the workingsurface, safety, labor intensity is small, compared with the traditional thin seammining, has more advantages. Therefore, this method has the value of miningapplication and research.Based on field application and theoretical analysis of this mining method,detailed outlines and summarizes this mining method. Proposed9kinds ofroadway layout-drilling sequence can be selected in different ways adapted tothe conditions as a design consideration.This important mining method of drilling parameters (drilling coal pillarwidth and width) were studied, and the concept of continuous porous drilling,drilling hole instead of the traditional way. Continuous porous refers augerdrilling thin seam mining, continuous drilling multiple (two or more) withoutdrilling intervals empty area and then leave some coal pillars. Based drillingmechanical characteristics, according to "beam" theory drilling width calculation,then the effective area of the theory of coal pillar width drill analysis givenformula. Formula should be treated according to different situations drillingempty area were selected, and pointed out the general method of continuousporous drilling parameters determined. The main conclusions were physical simulation study are as follows: in themining process stress coal pillar and rock to go through this process thatunaffected→affected while slowly increasing→rapidly increases→slowlyincreasing→decreases→trend in a certain stable value;Stress is a shift in thedirection toward the middle of the coal pillar in the middle of coal pillar bear themain load decreases sequentially to both sides;Drilling face of hard roofforming a great support structure by "Both sides of the border coal and rock-pillars-the coal wall",When there is a large area to pressure instability, the stopepillar coal overburden rock as a whole and cut coal caving boundary; undercertain geological conditions, drilling width of8meters and coal pillar width of2meters, coal pillar and impact of drilling surrounding rock deformationphenomenon did not happen, so the continuous porous drilling method isfeasible.Use numerical simulation FLAC3D, explore the stability of surroundingrock and coal pillar. Drilling surrounding rock and coal pillars in the horizontaldirection of tension and compression stress is very low on coal pillar and rockinstability little effect; surrounding rock and coal pillar mainly by vertical stressand the failure mode is mainly for shear failure.9kinds of roadway proposed arrangement-drilling sequence, drilling andcoal pillar width width is determined to optimize the auger mining methods.Master cylinder and surrounding rock stability of coal mining in favor of drillingpressure control. Theoretical analysis, physical modeling and numericalsimulation show thin seam mining auger drilling new way of thinking is acontinuous porous feasible. These results have a certain reference value for thinseam mining auger design.