Increasing Oxygen Mass Fraction in Blind Headings of a Plateau Metal Mine by Oxygen Supply Duct Design: A CFD Modelling Approach

Hypoxia problem has always been a difficult point in plateau tunneling projects. To solve this problem, a blind heading face in a plateau metal mine in western China was taken as the physical model, and the computational fluid dynamics was used to analyze the oxygen mass fraction distribution and oxygen-increasing effect in 1 m, 3 m, and 5 m roadway sections from the heading face. The optimal ventilation system was first built to obtain the optimum height and length of the airflow ducts. Then different cases with various oxygen supply duct designs were built in 2 scenarios. The results found that different oxygen supply duct design has significant influence on the oxygen distribution in the heading face. Also, each design has different optimal height of oxygen outlet. The oxygen supply effect is best when some small holes are made in the oxygen supply duct to diffuse oxygen to the working surface. The finding of this paper is helpful for effective and economical oxygen supply in roadway excavation of plateau metal mine and tunnel