Designing an underground ventilation system and fan selection

Abstract

Mixing of stale air with fresh air (short-circuiting of airflows) is a critical issue in any underground ventilation system. This study was done at Bogala mines owned by Bogala Graphite Lanka Ltd, where this type of mixing takes place in certain levels leading to a cyclic movement of stale air. The main objective of the research project is to design an underground ventilation system and to select fans to overcome these adverse effects and making ventilation more effective and efficient. As die mine is of complex nature, two particular levels at 205 and 240 fathoms were selected for the analysis, where the short circuiting of air is predominant. A detailed survey was carried out to measure the variations of airflow and frictional pressure drop along cross cuts, development drives and winzes in selected levels. The corresponding values of mine air resistance for airways were determined to generate a solution followed by suitable fan selection. Suggestions were made to improve the present ventilation system, which will enhance mine air quality increasing health and safety aspects of underground environment.