Research On The Prediction Of Water Accumulation In The Goaf Of The Ningtiaota Coal Mine

In the multi coal seam mining,the water accumulation in the goaf of the upper coal seam will seriously threaten the safe mining of the lower seam.How to accurately predict the water accumulation in the goaf after a certain interval has become a major problem in production.In this paper,Ningtiaota mine as the research object,establishing the three-dimensional numerical model of groundwater,using the numerical simulation method of mine predicted N1205 working face in the north limb and S1224 working face in the south limb goaf water quantity and researched on forecast method of goaf water quantity.Based on the summary of Ningtiaota mine geology,hydrogeology and mining data,the goaf water conditions are analyzed,the fully mechanized mining face of natural caving method of roof in goaf area is mainly affected by source of water,water channel and water space.The main source of water in goaf is mainly composed of coal seam roof,sandstone and fissure water,followed by meteoric water,surface water and unconsolidated aquifer water.The water channel is water flowing fractured zone.The 2-2 coal seam water flowing fractured zone is developed to bedrock layer,but in the Kaokaowusu ditch and Shixia ditch,it can be through the stone surface.The water space in the goaf of Ningtiaota coal mine is actually the volume of the voids between the falling blocks of the goaf and the confined wall.According to the hydrology geology unit of Ningtiaota mine in northern and southern flanks,The South will be generalized as aeolian sand strata phreatic aquifer and Salawusu group,Lishi group and Baode group relatively impermeable,water flowing fractured zone above the primordium of rock,water flowing fractured zone and 2"2 coal mined out area,a total of 5 structure layer.The north limb formation almost as Baode and Lishi group relatively impermeable,water flowing fractured zone above the primordium of rock,water flowing fractured zone and 2"2 coal mined out area,a total of 4 layer structure.According to geological model,using groundwater simulation software(GMS)to establish the numerical model of groundwater in South and NorthThe relevant concepts involved in predicting water volume of goaf are defined,including goaf water rock,water space,water speed,full of water and water parameters,given these parameters,especially the prediction method of goaf water quantity.Goaf water on the north limb of Ningtiaota coal mine N1205 and south S1224 working face was predicted.It is result that:N1205 working face of fully closed goaf water space is 892125m3,can discharge goaf water space is 41179m,the water velocity is 9.33m/h,full closed goaf filled with water for 10.91 years,can discharge goaf full of water for 0.51 years,closed goaf water quantity 892125m3,can discharge goaf water quantity is 41179m3.S1224 working face of fully closed goaf water space is 1003353m3,can discharge goaf water space is 35624m,the water velocity is 124.65m3/h,full closed goaf filled with water for 0.91 years,can discharge goaf filled with water for 11.91 days,full closed goaf water quantity is 1003353m3,can discharge gob water quantity is 35624m.The prediction results are in good agreement with the actual ones,which shows that this method can be popularized and applied.