6 www. refrigerationandaircon. co. za RACA Journal I February 2026
MINE VENTILATION FEATURE SERIES mine ventilation
Richards suggested that while these findings might seem unconventional to some, they are actually practised in other countries globally. He challenged the audience: " I think we need a mind change, a mind shift." While not universally applicable to all mines, he firmly believes that for simple, conventional truck and shovel mines, these benefits are undeniable.
ADDRESSING PRACTICAL CONSIDERATIONS AND THE PATH FORWARD
The presentation sparked insightful questions from the audience, probing deeper into the practical implications of such a paradigm shift.
One attendee questioned the DPM contamination at the ramp entrance in a forced downcast model, where people entering the mine would be exposed. Richards acknowledged this but countered that the illusion of a‘ clean’ conventional ramp intake is false; diesel vehicles travelling up and down naturally contaminate it. He clarified that it becomes a design choice: either DPM and heat accumulate at the bottom of the mine, or they are ejected at the surface entrance. The overall conditions in the ramp remain similar; it ' s a matter of where the worst conditions are located.
Another attendee raised concerns about the heating of intake air by a downcast fan and the practical issues of cooling trucks in a co-current airflow within the decline. Richards affirmed that both are valid concerns. Compressing air in a shaft
A slide from the presentation.
and adding fan heat would marginally increase the intake air temperature. Similarly, while loaded vehicles move slower in the decline, potentially aiding cooling, maintaining adequate ventilation at around six to eight litres per second is crucial to cool the trucks. He reiterated that his findings are not a " silver bullet " or a universal answer; every project is unique, requiring tailored solutions that cater to specific client needs while being mindful of these practical considerations.
Richards concluded by urging a rethink of traditional mine ventilation. Leveraging natural thermodynamics can unlock major improvements in safety, efficiency and cost – especially in diesel and trackless mobile equipment mines. RACA
6 www. refrigerationandaircon. co. za RACA Journal I February 2026