Parametric study of airflow separation phenomenon at face area during deep cut continuous mining

Abstract

It is well known that a major ventilation problem during deep cut mining is delivering the required amount of air into the immediate face zone. Line brattice face ventilation systems are commonly applied for medium and low coal seams in room and pillar mining method utilising continuous miner. It is assumed that the blowing curtain, as opposed to the exhaust curtain, generally achieves greater efficiency in delivering air to ventilate the immediate face zone. However, in real mining conditions both, the blowing and the exhaust curtain face ventilation systems suffer from one significant disadvantage – the intake air separates early from the rib and does not fully penetrates to the immediate face zone. This phenomenon is called flow separation. The portion of the intake air reaching the face can be <20% with the exact amount being a function of various parameters associated with the mine and ventilation design. The results presented in this publication clearly shows that curtain tight-rib distance, width of the entry, and curtain setback distance govern the flow behaviour at the face area. The performed analysis confirmed that changes in the intake air quantity have no significant impact on the flow patterns and the amount of air delivered to the immediate face zone.