Development of an Expert System for Unplanned Fall of Ground Assessment in Coal Mine Excavation Intersections

Abstract

ABSTRACT Unplanned roof falls in tunnel intersections are commonly associated with casualties, accidents, economical loss and therefore pose a serious threat for coal mine profitability. Despite the technological advance in ground control, fall of ground (FoG) in tunnel intersection often occur. Subjective data and information are inevitably used in the design of coal mine development excavations which contribute to unplanned ground instabilities. These aspects are not considered in conventional design tools. Hence, the aim of this paper is to propose expert systems capable of adequately quantify the relationship between the unplanned roof falls, support methods and the geology. Fuzzy inference system (FIS) which uses fuzzy logic to discern relationships between data is implemented in this study. FoG in tunnel intersection data were compiled from several coal mines. Expert knowledge approach was used to construct the FIS. The system parameters include the FoG size, geology, types of support and groundwater conditions. Overall, the results indicated quite good agreement with the field observations. The correct classification rate varied between 67 and 80%. It is concluded that FIS could be used to assess FoG in tunnel intersection in coal mines. INTRODUCTION Despite greater awareness of the environmental implication of the coal business, there is still a considerable demand for it globally. The industrial development in China, India, and Southeast Asia countries were recently reported to be the main drivers of the 0.7% rise in worldwide coal consumption (Zhironkin and Cehlár, 2021). Meanwhile, there are a wide ranges of safety issues associated with coal mining. One of them is fall of ground (FoG) which is a generic term used to describe loose rocks falling from excavation faces (roofs and side walls). Unplanned FoG in roadway intersections in coal mines present a serious threat to mine safety, as intersections are by far the most common area for FoG to happen (Mueller, 2010; Mark and Gauna, 2017). It can occur in many geological and operational situations; even with primary and secondary support structures. There are several reasons for it to happen which include over-spanned intersections, non-sufficient support, excess horizontal stress, and weak geology with low strength of rock intersection.