Karst Hydrogeological Characteristics And Drainage Evaluation In Pan'er Coal Mine

Huainan coalfield is located in the southern margin of North China Coalfield,Under the multi-stage tectonic geological process,the hydrogeological conditions are extremely complex.There is a certain hydraulic connection between the deep karst water and the aquifer of coal measures,which threatens the safety of coal mining.Pan'er coal mine is located in the middle area of hydrogeological unit in Huainan coalfield.The mining of group A coal seam is not only affected by limestone water of Taiyuan Formation,but also threatened by karst water of Ordovician.The thesis systematically analyzed the karst hydrogeological conditions in the mining area from the aspects of characteristics of the karst water-bearing medium,the dynamic characteristics of the groundwater,the hydraulic connection between the aquifers,by using the data of C3? group limestone drainage and Ordovician water inrush process in Pan'er coal mine.The hydrogeological conceptual model and mathematical model in C3? group limestone and Ordovician limestone aquifers were established,and identified and verified.Finally,the different drainage scenarios are evaluated by using the identified model and the theory of water inrush coefficient.This provides a basis for the design of the drainage scheme to ensure the safe mining of group A coal.The main achievements and understandings are as follows:(1)The limestone of C3I in Carboniferous has weak water abundance and poor recharge conditions,Ordovician limestone aquifer has weak to strong water abundance,good runoff conditions and a certain range of recharge.The hydraulic connection between limestone aquifer of Ordovician and C3? limestone aquifer of Carboniferous is close,but the hydraulic connection between limestone aquifer of Ordovician and C3?and C3? limestone aquifer of Carboniferous is poor.(2)According to the hydrogeological conditions,the hydrogeological conceptual model and the three-dimensional mathematical model of confined aquifer instability are established respectively.After the model identification and verification,it meets the expected requirements and has reliability(3)Based on the identification and verification model,combined with the water inrush coefficient theory,it is found by simulation that:When the drainage amount of group C3? limestone in the study area was 30 m3/h,the water inrush coefficient was lower than 0.06 MPa/m after 450 days of drainage.When the drainage amount of Ordovician limestone is 100 m3/h,and the water inrush coefficient is lower than 0.06 MPa/m after 360 days,which meets the requirements of safe mining.(4)Combined with the surface regional control project,the drainage scheme was designed.Under the condition of grouting,the safe water pressure of mining can be reached in 120 days when the amount of Ordovician limestone is 100 m3/h.The above results provide an important reference for the prevention and control of karst water disaster in Pan'er coal mine,which has potential social and economic benefits.Figure[84]Table[6]Reference[89]...