Justification of a method to ventilate long blind drifts with fans spaced along the ventilation duct with its discontinuation

This article discusses various ventilation designs for long blind drifts. The leakage coefficients were calculated for the rigid and flexible pipes. The leakage coefficient for the flexible pipeline was defined using the Protan Ventiflex software. The calculation was carried out for the drifts with the length ranging from 100 to 5500 m with a step of 500 m, the pipeline diameter was taken to equal 2 m and the air flow rate at the face was 20 m3/s. It was revealed that when using a rigid ventilation pack the delivery coefficient decreases significantly with the increased length of the drift. With the total length of the pipeline of 5500 m the value of the leakage coefficient for the rigid pipeline is equal to 3.16, and for the flexible pipeline it stands at 1.57. The full pressure diagrams were analyzed when using the ventilation method with a cascade spacing of the fans along the duct. As the result of this analysis, it was revealed that when the length of the ventilation duct located after the second fan changes, the depression zone between the first and second fans shifts, which results in a failure to supply air to the face. In order to avoid such depression zones, it is proposed to use discontinuities before each subsequent fan.