The Research and Application of Ejectors in Managing Low Oxygen Levels in Workface Corners.

Abstract

During routine retreat mining operations, the corners of mine workfaces are susceptible to low oxygen phenomena, which can pose breathing challenges and other health risks to workers. To address this issue, a prevention and control technique based on the principle of ejectors was developed and implemented. The study analyzed the working mechanism of ejectors in mitigating low oxygen conditions and integrated this technology into field applications. After 1 week of operation, oxygen concentrations consistently exceeded 18.5%, demonstrating effectiveness. By evaluating oxygen control performance across three shifts with varying ejector placements, the optimal configuration was determined to involve positioning the ejectors at a height of 1.5 m and a horizontal distance of 1.5 m from the target area. Under these conditions, the difference in oxygen concentration before and after intervention exceeded 4.5%. An ejector wind speed of 8 m/s effectively eliminated low oxygen zones in the return air corners, maintaining overall oxygen levels above 19%. Furthermore, numerical simulations of oxygen concentration distribution revealed that low oxygen zones were predominantly located within a 3 m radius in the direction of travel and downward. The use of ejectors significantly improved oxygen levels in these regions.