Risk evaluation of water disaster from paleo-sinkholes

Paleo-sinkholes can be classified as three types as follow in term of substance features of fillings, degree of compaction and consolidation, permeability, and so on. Most of them are dryness and water barrier, those at modem Karstic runoff or discharge zones and under water table have potential risk of water inrush. The permeability of paleo-sinkholes the numerical modeling are used to evaluate risk of water inrush from paleo-sinkholes. Risk evaluation by numerical modeling shows that water inrush may occur from them under mining condition even for non-permeable paleo-sinkholes originally, So, if there is not water prevention work, it is necessary to set up water barrier pillars for paleo-sinkholes.