Analysis of Ventilation System and Assessment of Hazards in the Process of Progressing Liquidation of Workings in Mine ‘S’

Abandonment of underground mines of a complex multi-level structure is usually done in a stepwise way. At each stage, the performance of the ventilation system must be adjusted to current structure of workings and the liquidation of related activities. The ventilation system must not only provide relevant working conditions of the liquidation but also ensure safety, taking into account issues like the fan operation stability or gas and fire hazards. The basic objective of the article is to present the plan of mine workings liquidation taking into account natural hazards and to analyse the air flows during the progressing liquidation of the mine workings system. Performance of the above analysis requires the knowledge of the following data: schedule of mine workings liquidation, structure of the considered ventilation system, values of parameters describing the air flow in the workings system, characteristics of working fans. To obtain the data, partially via ‘in situ’ measurements in the mine workings allows using a modern computing tool, which is ventilation engineer’s software system Ventgraph. Computer programs of this system are used in numerous Polish mines and in some mines worldwide. The results obtained from their application are useful for the determination of ventilation system safety objectives. The computer database held by the mine ventilation department was used for the study. Because of the fire hazard, the article pays particular attention to the pressure (aerodynamic potential) distribution in the ventilation nodes for the sequence of stages of the ‘S’ mine ventilation structures of mine workings liquidation. Results of the case study incorporating 14 variants simulated with the Ventgraph software have been presented in the forms of graphs and tables. In conclusion, some guidelines for general rules of such gradual liquidation have been outlined.