Study On Reasonable Staggered Distance And Strata Behavior Regularity Of Simultaneous Mining In Close Distance Coal Seams In Guo’er Zhuang Colliery

This article combined with the condition of18m average distance from Xiaomei toDamei in Guo’erzhuang Colliery, it aimed at systematical study on determining thereasonable staggered distance when close distance coal seams mining. This article wasbased on practical research and information, using the theoretical analysis method, itdemonstrated the theory of reduced pressure area was reasonable when close distancecoal seams mining in Guo’erzhuang Colliery. At the same time, we adopted the methodof analogy simulation study, computer numerical simulation research and industrial teston site to simulate and analyze the staggered distance when close distance coal seamsmining. Finally determined that it was reasonable to place Damei working face inreduced pressure area formed from Xiaomei mining, reasonable staggered distance wasfrom15meters to25meters.Due to the theoretical analysis, the maximum damage depth of coal seam floor was13m when Xiaomei coal seam mining, in which case, the distance of two coal seamswas18m, Xiaomei coal mining could not affect Damei seam, and Damei coal seamcould form stable structure, so Damei could mine securely and stably when workingface placed in Xiaomei reduced pressure area. By this time, Damei coal roof pressurewas low, and it is easy to support the roadway, so it was good to place Damei workingface under the reduced pressure area of Xiaomei mining.We made the similar material model in the similar material model, and thegeometric similarity ratio of the similar material model was1:100. When Damei facewas30cm away from Xiaomei face, we found a vertical fracture in Damei roof, bymonitoring the stress sensor in Xiaomei floor, there was an elevated area of rearabutment pressure behind Xiaomei working face25~35cm. When the staggered distanceof two working face in range of15~25cm, mining pressure of Damei face was low andit was good for simultaneous mining.Through computer numerical simulation of two coal seams simultaneous mining,the up and down coal seams had less impact to each other when staggered distance was15~25m, the elevated area of Xiaomei was basically disappeared, the range and thepeak of abutment pressure in front of Damei reduced, so the staggered distance between15meters and25meters would benefit two coal working faces at the same time. In this way, mine ground pressure showed relaxatived and it made good mining environmentfor simultaneous mining.Integrating with local industrial test through observing every pressure indicator, atthe staggered distance of15~25m, analysis confirmed that the hydraulic support load ofXiaomei dropped slightly and every pressure indicator of working face appeared lower.The range of advancing abutment pressure obviously decreased in Damei air return way,the peak of the pressure also dropped remarkably, hydraulic support load stayed at lowerlevel, no roof cracked and coal wall fallen was found in working face, through fieldobservation we concluded that the reasonable staggered distance of simultaneousmining was15~25m.Research showed that Damei working face placed in Xiaomei reduced pressurearea as two coal seams mining in Guo’erzhuang Colliery, hydraulic support load was inlower level and roadway ground pressure appeared weakly when the staggered distancekept in15~25m. Therefore, choosing this staggered distance as the reasonable staggereddistance would play a positive role in roadway supporting and working faces ofsimultaneous mining seams.