Risks Induced by Room Mining Goaf and Their Assessment: A Case Study in the Shenfu-Dongsheng Mining Area

A large area of room mining goaf has been left throughout the history of coal mining worldwide. However, because the pillars cannot perpetually retain stability, the sudden collapse of a large area of goaf can occur. The existing large areas of room mining goaf have become a potential source of geological risks in mining areas with room mining goafs worldwide. To elucidate the distribution and state of the goafs, a survey of the characteristics of goafs was carried out by geophysical exploration and drilling methods. From this complete survey of room mining goafs, this paper has outlined eight common goaf risks, emphasizing the types of goaf risks that require precautions, and the formation mechanisms of each goaf risk has been analyzed. Considering that the occurrence of a risk may lead to several other risks and there is a certain interaction between the risks, more specific room mining goaf risk forms, causes and scopes of influence have been listed. It is advantageous to use a support vector machine, which is useful for small-sample problems, to assess the goafs. A support vector machine assessment model of room mining goafs was established, and sample training and verification were carried out. Comparing the risk assessment results with those of the field investigation, it can be seen that the evaluation model has a high accuracy. This work can greatly contribute to the prediction and prevention of risks induced by room mining goaf.