Study On The Prediction Of The Water Inrush From Coal Seam Floor During Open Coal Mining

In recent years, due to the mining of coal resources and mining depth increasing intensity, the underground mining gradually transformed into open-pit mining, leading to coal geology and hydrogeological condition become increasingly complex. During coal mining, coal mine water inrush accidents occured again and again, bringing the most serious hazards to the country and the people, which greatly increases the difficulty and cost of coal mining.In this paper, taking a mine for the study, which in Inner Mongolia Erdos City Etuokeqi QipanJing town, intends to mining the Carboniferous Taiyuan 16# coal mine, threatened by confined water within Ordovician limestone, Using petrology, structural geology, groundwater dynamics method, analysis and calculation the mine groundwater recharge, runoff and discharge conditions, the degree of development of seam floor fissure karst, development rules, impermeable layer impermeable performance. Evaluating and predicting water inrush risk, assuming water inrushing, Using groundwater dynamics formula to calculate water inflow capacity, propose the technical countermeasures of preventing water inrushing, draw the following conclusions:1.The paper analyzes the water inrushing mechanism, depending on the water inrush time, place, water inflow capacity, water inrush sources and other factors, divide the types of water inrush, integrated mining geological conditions, draw the most likely types:From the point of view of mining influence relations, the mine belongs to mining influence type; from water inrush dominated factor analysis, this is a normal mine type.2. Water inrushing phenomenon is caused by complex geology and mining influence phenomena and other factors, combined with the actual mine hydrogeological conditions, summarized main factors are:① water sources;② geological structure;③ lithologic structure;④ mining space and mining methods; ⑤ stress.3.With water inrush coefficient method and "the three zones" method, evaluate the safety of mining above the confined aquifer in 16 coal mine, results from the two methods, mining southwestern confined area belongs to the water inrush threatened area, there is the possibility of water inrush.4.Based on groundwater dynamics theory, predict water inflow with a steady flow method, when permeability coefficient is 0.0114m/d, forecasting water inflow is 384 m3/h, moderate water inrush point; permeability coefficient is 0.1043m/d, water inflow is 1441 m3/h, large water inrush point.5.According to the evaluate result about water inrush risk, put forward some technical methods, such as,hydrophobic antihypertensive bottom grouting transformation and damming up with curtain. Provide certain technical guidance for mining.