Evaluation Of Limestone Water Drainage And Water Inrush Hazard In 101 Mining Area(expansion)of Qinan Coal Mine

With the increasing demand for coal resources in China,the coal mining has gradually developed to the conditions of large mining depth and complex geological.But with the increase of coal mining depth,the work of coal mining is facing more and more risks.Among them,the coal seam mining is threatened by deep floor limestone water which is becoming more and more serious.Qinan coal mine is a typical Huabei type coalfield.Since it was put into production,there has been no serious water inrush accident.However,there is a serious water inrush accident which occurred in the neighboring Taoyuan coal mine.In order to prevent the occurrence of such serious water inrush accident and make it safe mining in Qinan coal mine.It is necessary to study the deep limestone water in Qinan mine.On the basis of consulting the relevant literature about the prevention and control of limestone water at home and abroad.The Qinan coal mine 101 expansion zone was taken as a research object.The geological and hydrogeological conditions of the study area were systematically analyzed.The information about hydraulic contact between limestone aquifer,fault conductivity,water resistance and water filling source was obtained in the study area.Firstly,the hydrogeological conditions of limestone aquifer in Taiyuan Formation of the study area are quantitatively analyzed by using the methods of hydromechanical thermodynamics,hydrochemical kinetics and geology and hydrogeology.Secondly,the hydrogeological parameters of the study area are calculated by using Aquifertest software,and the results are compared with the results of the drainage test.Based on the above analysis,the hydrogeological conceptual model and its mathematical model are established by analyzing the aquifer boundary,the structural thickness and the fill diameter and discharge conditions of the floor limestone.And the hydrogeological parameters are identified by software simulation.Meanwhile,combined with the geological and hydrogeological data of the mining area and the vulnerability index method is used to analyze the risk of water inrush in the study area.The prediction model of water inrush from coal seam floor was established.And according to the frequency histogram analysis of water inrush vulnerability index calculated by each unit in the study area,the threshold of water inrush vulnerability zone was determined.Thus,the image of water inrush danger degree was established.Reasonable assessment and regionalization of water inrush risk of coal seam floor in the study area were achieved.Finally,according to the water quality analysis data of aquifer,the discriminant model of water inrush source is established,which provides the most direct and effective means for rapid discrimination and analysis of water inrush source.Through the above research,this paper drew the following main conslusions:(1)According to the conceptual model of hydrogeochemistry,the study area belongs to the deep buried karst area where the groundwater circulation alternates slowly and the water-rich water is poor.(2)In the study area,the recharge of the limestone aquifer of Taiyuan formation in the north and the fourth aquifers of the Cenozoic loose layer in the South concealed head area are relatively weak,the runoff condition is poor,the permeability coefficient is low,and the water conductivity is weak,which reflects that the karst of the limestone aquifer of Taiyuan formation is extremely undeveloped,the connectivity is poor and the whole water rich is very weak.(3)In the process of dewatering test,the change of water quality characteristics of limestone water of the Taiyuan formation is weak,and the water quality characteristics of the limestone water of the Ordovician in the mining area is distinctly different.It shows that there is no hydraulic connection between limestone water of the Taiyuan formation and the limestone water of the Ordovician.The limestone aquifer of the Taiyuan formation and the limestone aquifer of the Ordovician are considered as two independent hydrogeological systems.(4)The southern part of the study area is a dangerous area of water inrush.The main reason is that there is a high water level area near 2005-1 observation well in the south and the water pressure is high.The high water pressure makes it easy for the ash water to break through the 10 coal floor water resisting layer and enter the mine.