A method for transient simulation of integrated ventilation and cooling systems in deep-level mines

Abstract

Mine ventilation and cooling systems ensure adequate air temperature and flow in underground working areas. These are large and complicated systems that are integrated and interdependent. As underground mines expand to deeper and hotter levels where ore reserves are found, the efficient operation of ventilation and cooling systems becomes increasingly important. Simulations are vital tools in the planning and optimisation of mine ventilation and cooling systems. The dynamic nature of underground mining operations, fluctuating ambient conditions, and dynamic cooling systems lead to a system that is seldomly in a steady state. Only a simulation that incorporates a true instantaneous heat flux model can simulate the thermal history effect seen in deep-level mines accurately. Literature has shown the benefits of using true transient simulations that incorporate the thermal history effect. These studies applied true transient ventilation simulations to theoretical models or sections of deep-level mines and compared them with conventional steady-state simulations. There was therefore a need to apply a true transient simulation to entire mine ventilation systems and to integrate transient cooling simulation. This study developed a novel methodology for simulating integrated true transient ventilation and cooling systems for underground mines. This method incorporated the thermal history effect and can practically be applied to entire deep-level mine ventilation and cooling systems with different infrastructure and mining methods. The new methodology was used to develop simulations of three case study deep-level mine ventilation systems. Two of these case studies had integrated cooling systems providing secondary cooling to the mine. The case studies showed that a true transient simulation could accurately predict the underground airflow and temperatures. Comparisons with a conventional steady-state simulation showed that the new true transient simulation had increased accuracy, which improved planning and optimisation. The case study simulation showed an average improvement of 1.0°C in the maximum error of temperature predictions. The improved accuracy further validated the true transient simulation in real-life applications.