Characteristics, detection, and prevention of karst sinkholes: a case study in Laiwu iron ore mine areas, Shandong Province, China

Karst-related sinkholes are globally recognized geohazards that can be triggered by mining activities. Totally, 136 sinkholes have occurred in the Laiwu iron ore mine area of Shandong Province, China. At the surface, the sinkholes are mostly round or oval shaped. Most are ceiling collapse sinkholes, and they have caused road and building damage, destruction of farmland, connection of surface and ground water, and groundwater contamination. Based on analysis of characteristics on karst sinkhole, geological and hydrogeological conditions, the proposed key factors of the karst collapse in the study area include soil characteristics, degree of karst development in soluble rocks, faults, folds, groundwater dynamic conditions, and human engineering and mining activities. A 300-m-long, 40-m-wide, and 25-m-high cavern was identified with high-density electrical resistivity imaging. Complex solutions were proposed to mitigate karst collapse in the iron ore mining area.