Prediction Of Water Inflow In An Iron Mine In Qinhuangdao, Hebei Province

Mine water inflow is an important indicator to determine the complexity of hydrogeology condition of the ore deposit,it is related to the safety and cost of mine production,which has a great influence on the economic and technical evaluation of the deposit;and it is an important basis for the mine production design and production department of formulating mining scheme,determining mine drainage capacity,formulating well-precipitation and prevention measures and designing drainage system and equipment.This paper took an iron mine in Qinhuangdao,Hebei province,as the research object,to study the prediction of mine water inflow,not only has a certain theoretical significance,but also has a certain practical value.On the basis of analyzing the geological conditions,combined with drilling data,it established the 3D hydrogeological structure model of mining area with GMS,and systematically analyzed the water-resisting layer characteristic of mining area from east-west,south-north directions and combination sections.The result shows that,the top of the mining area is completely covered by the thick Quaternary first aquifer,the surface has small fluctuation;the first aquitard is continuous distribution,can cut off the hydraulic relation between the Quaternary first aquifer and the Quaternary second aquifer;the clay layer at the bottom of the Quaternary,is discontinuous distribution,only found in the northeastern and southwestern parts of the mining area,and the thickness of it is small;bedrock strong weathering belt is directly contact with Quaternary,it is continuous distribution,in natural state,it has certain effect on obstructing the hydraulic relation between the Quaternary second aquifer and bedrock fissure water,and there is no separation between the weathered fissure aquifer and the structural fissure aquifer.On the basis of the 3D hydrogeological structure model,combined with the recharge,runoff and discharge of groundwater system of the mining area and the water filling factors of the ore deposit,he hydrogeological conditions was generalized,and the hydrogeological conceptual model of the mining area was established,then combined with the hydrogeological conditions,the corresponding mathematical model of groundwater was established according to the hydrogeological conceptual model,and then the numerical model was set up by using Visual MODFLOW and GMS.The model was tested by using the data of steady flow field and water level of observation hole of pumping test,and the parameters of the model were adjusted by the combination of manual and PEST modules.The parameters of the identified parameters and the water level of the observation hole were used to analyze the sensitivity of the parameters,the result shows that the permeability coefficient of the fractured aquifer is the most influential factor to the calculation of the water level.The mine water inflow of different mining steps in south and north ore section were predicted by the identified numerical model,the prediction results show that when the mining step is-150 m,the mine water inflow of north and south section of separate mining were 7020m3/d,22950m3/d,combining mining mine water inflow were 6500m3/d,22100m3/d;when the mining step is-280 m,the mine water inflow of north and south section of separate mining were 9880m3/d,44200m3/d,combining mining mine water inflow were 9100m3/d,39950m3/d;When the north section of the ladder is-385 m,the southern mining area mining bench is-419.5m,the mine water inflow of north and south section of separate mining were 11700m3/d,71400m3/d,combining mining mine water inflow were 11180m3/d,66300m3/d.