Oval Ducts in Mining Ventilation Systems: Optimization of the Operation Costs and Increase of Clearance in Mine Roadways

Abstract To optimize the clearance in mine roadways and reduce operation costs, new oval ducts can be used in auxiliary ventilation systems instead of conventional circular ducts. In this paper, an experimental study was conducted to investigate the performance of conventional circular ducts compared to two types of oval ducts with equivalent cross-sectional area. The laboratory tests were conducted on a test bench under various operating conditions using a 45-kW axial fan with speed control and flexible ducts 20 m in length and a cross-section of 0.78 m 2 . Additionally, a mining development with a cross-sectional area of 15.57 m 2 in a deep mine was selected as a case study to analyze the increase in clearance and the optimization of the operation costs. A novel analytical model was developed based on the results of the experimental analysis. Variable friction coefficients along the ducts and different duct qualities were considered to determine the air leakage as well as the fan power requirements in the case of leaky ducts. The results obtained show an increase in pressure loss in the oval ducts, resulting in greater energy consumption for the ventilation system. However, a reduction in excavation costs of 6.4% can be achieved when the height of the mining developments is reduced using oval ducts. Finally, the results indicate that the use of oval ducts allows reducing operating costs and improving the efficiency of mining operations.