Analysis of sinkhole occurrences over abandoned mines using fuzzy reasoning: a case study

In Korea most of the old mine workings were worked with room and pillar method or sublevel caving method and today they possess great possibility of surface subsidence especially for shallow depth mines. In most of the cases, mine roadways, rooms and pillars are irregular in shape and information about the local geology is uncertain. For these reasons, it is difficult to standardize the estimating method of subsidence especially sinkhole type over abandoned mine area. This paper describes the application procedure for the fuzzy reasoning techniques to analyze the possibility of sinkhole occurrences over abandoned mines. This technique is implemented in software which can simplify the analysis procedure and present the possibility of sinkhole subsidence without having precise information about local geological/mining conditions. This technique has been applied to forecast sinkhole possibilities at Bonghwa site where a massive sinkhole has already been occurred.