Optimal refuge chamber position in underground mines based on tree network

Safety is a critical concern in underground mining. Operations should be designed according to a vision of zero accident and fatality. A refuge chamber is a station where worker lives are maintained throughout an emergency until they are saved. Given that workers perform their duties in different areas of underground, the number of refuge chambers and their locations are of paramount importance as workers must be able to access them rapidly. Furthermore, the task of refuge chamber localization needs to consider the fact that the number of workers in a different area and the structural characteristics and stability conditions of these areas will not be identical. This paper aims to determine the optimal locations of the refuge chambers in the underground network considered as a tree. Initially, a formula quantifying the importance of each worksite is developed. Then, two main strategies are presented as feasible localization solutions: A recursive solution to the 'Absolute Weighted P-centre Problem' and a spiral approach to the 'Total Covering problem'. The functionalities of the proposed approaches are demonstrated by case studies. Results show that the proposed methods can find viable locations for refuge chambers while fulfilling varied maximum safety distances of each working area.