Ventilation-on-demand and the Venetia Underground Project The ongoing evolution of the Venetia diamond mine from a surface to an underground operation is preserving one of the country’s most prominent sites while setting new benchmarks for sustainable mining. MCA talks to Russell Hattingh, MD of BBE Consulting, about the role of advanced ventilation-on-demand in helping Venetia to deliver the mine’s enhanced air quality and operational efficiency.
“V entilation-on-demand (VoD) is more about air- flow management than instantaneous optimisa- tion of the ventilation system’s performance. That does not diminish the role of real-time control. Rather, effective VoD relies on a well-designed ventilation system that can be dynamically adjusted within safe and ef- ficient operating limits. First and foremost, it's about right-sizing and ensuring proper airflow distribution. Ventilation systems need to be properly integrated into each mine's specific infrastructure, with the capability to meet immediate needs, with built-in expansion plans to meet the needs of the mine's future progress,” begins Russell Hattingh, managing director of BBE Consulting. For the development of the new under- ground mine at Venetia, BBE was involved from the initial pre-feasibility phase. A new primary air-cooling and ventilation system comprising two water-chilling refrigeration machines and multiple air coolers was de- signed and commissioned by BBE in August 2022. “Venetia is now looking at incorporating a ventilation-on-demand capability to man- age air quality for all underground workers, ventilating specific working areas according to their needs,” notes Hattingh. VoD isn’t usual in a conventional mine, he says, but ventilation always needs to be managed. “It’s a bit of a buzzword that always comes down to ventilation management. You might call saving money optimisation, but the whole purpose behind a VoD-type system is to manage the mines' ventilation system properly,” he argues. Ventilation-on-demand, he continues, can be as simple as opening and closing dampers and manually switching fans on and off. “But its purpose must be ventilation management so that the air is being sent to where it is needed and not to dormant areas that don’t need it,” he continues. To manage a ventilation system properly, however, one needs to know what to do and what the effects will be. There are two aspects of this knowledge: the first is safety, which is the most important, as the underground
ventilation system exists to keep miners safe and working in conditions that promote productivity. Also important is knowing the required air volumes in each area and how opening a damper serving one area will affect the supply to another. “This is where a more complex con- trol system sets itself apart. Modern digital control systems ensure the specified airflow reaches its destination, such as the new ore drive. Manual adjustments can’t deliver the certainty that a control system can. Over- supplying one production drive might mean
under-delivering to another,” he points out, adding that proper ventilation management means getting the right amounts of air to wherever people are working. Primary and secondary ventilation Regarding ventilation design, he notes two critical aspects: primary and secondary venti- lation. Secondary ventilation is where it starts.
For the Venetia diamond mine, BBE designed and commissioned a new primary air-cooling (BAC) and ventilation system comprising two water-chilling refrigeration machines and multiple air coolers in August 2022.
Venetia is using a progressive sublevel caving operation, where multiple drives will be developed, but only a few will be mined at any one time.
30 ¦ MechChem Africa • January-February 2025
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