Improving the operational efficiency of deep-level mine ventilation systems

Abstract

Deep-level mines are faced with many challenges that influence and affect the gold production rate. Deep-level mines have unfavourable working conditions due to the extreme depths, additional heat sources, confined spaces and high temperatures. Ventilation of working areas is a challenge due to the intricacy of underground networks after years of mining and development. As a result, ventilation systems are outdated and lack optimised control. Literature shows numerous studies about the aid of simulations in mine ventilation with regards to fan configurations, fan impeller improvements and theoretical approaches to improving the ventilation system. This is beneficial but requires implementation on the underground ventilation network to realise results. In order to do so, a comprehensive strategic approach is required. Ventilation systems require effective planning and problem-solving techniques to ensure a prolonged sustainable ventilation network. A generic solution strategy was developed to identify the network inefficiencies, develop a suitable solution strategy with the aid of a simulation and implement the strategy in an effective manner. The generic solution strategy was implemented on a South African gold mine –Mine X. Upon implementation of the strategy, the main inefficiency identified within Mine X's ventilation system, was numerous inactive working areas that still received ventilation. The solution developed aimed to reroute the air to the active working areas with the use of auxiliary ventilation components. The concept of the solution was simulated which yielded an increased system resistance, airpower and better surface fan performance. The actual results yielded an average increased airpower of approximately 57 kW, a decreased system resistance of 0.002 Ns2/m8 and an increase in surface fan efficiency of approximately 9%. As a result of the improved efficiency, the surface fan configuration was optimised. Instead of the typical three surface fans, only two were used to achieve the desired ventilation during the summer period. The new fan configuration sustained the working conditions and resulted in an additional electrical power reduction of approximately 20 400 kWh. This equates to R3.2 million p.a.