Ecological function restoration of mining-damaged aquifers:Conceptual connotation,theory,and technical framework

JU Jinfeng; LI Quansheng; XU Jialin; WANG Chenyu

Abstract：In response to the current research status of water conservation coal mining in China and the technical re-quirements for ecological restoration in mining areas,it is proposed to carry out research on ecological function restora-tion of mining-damaged aquifers and incorporate it into the green mining technology system.On the basis of fully elab-orating the concept and connotation of ecological function restoration in mining-damaged aquifers,a theoretical and technical framework was constructed mainly based on the law of water loss in mining aquifers and key technologies for water runoff interception.The current research progress and future research directions were analyzed.The damage,water loss,and ecological function degradation of aquifers are essentially caused by strata movement and crack devel-opment caused by coal mining.Therefore,ecological function restoration research should be carried out on the basis of fully understanding the water loss mechanism of aquifers.Deeply reveal the distribution of water loss paths and the dis-sipation law of water flow dynamics in aquifers,and take the mining affected area with concentrated water loss flow as the key target area for restoration.Reasonably use methods such as"repairing while mining"and"repairing post mining"to implement water flow channel sealing and restoration.At the same time,it is necessary to fully uti-lize the self-healing mechanism of mining-induced rock fractures and its self recovery effect on aquifers,and carry out research and practice on ecological function guided restoration of mining-damaged aquifers;Based on the self-healing and permeability reduction mechanism of chemical precipitation generated by water-gas-rock interactions on wa-ter-conducting fractures,a remediation technology path for ecological function restoration of aquifers is proposed by in-jecting remediation reagents that can produce chemical precipitation with groundwater into the fractured rock mass be-low the aquifer,in order to promote the adsorption consolidation of sediment in the fractures and block the channels.On this basis,the current research status of using iron/calcium chemical precipitation for water conducting fracture re-pair and permeability reduction is elaborated,and it is proposed that future research should focus on developing chemi-cal precipitation induced generation strategies that are conducive to efficient sealing of different types of water flow channels.The research is expected to provide reference for groundwater protection and ecological restoration dur-ing coal mining in ecologically fragile mining areas in the northwest of China.