Smart-VOD operations manager Stuart Twiss sat down with Australian Mining to provide a fresh perspective on ventilation on-demand.
To increase the profitability of underground mining operations, it’s essential to maximise mineral extraction while controlling costs. Significant among these costs is underground ventilation, which is critical to ensuring safe and efficient underground operations.
As Smart-VOD operations manager Stuart Twiss explained, there are ways to minimise ventilation costs.
“Historically, the capital expenditure (capex) of ventilation system components were a major part of total ventilation costs, leading to standardised inventory with limited fan size options,” Twiss said. “This often resulted in oversized fans running inefficiently, especially during shorter development stages of a drive.
“Ventilation requirements evolve as declines and drives are developed. Optimising ventilation starts with a good ventilation network designed by experts. The network should effectively and efficiently ventilate working areas without impacting operations.”
A ventilation on-demand (VOD) system overlays a well-designed ventilation network and helps to optimise the system.
“VOD provides a practical approachto energy savings by tailoring ventilation needs based on real-time demand by recognising that most mine drives are vacant for large portions of the working week,” Twiss said.
“In a drive with a dual-stage fan, both stages may be required during bogging, shotcreting and blast clearance processes, whereas a single-stage fan provides sufficient air for other activities.
“Whole-of-mine VOD systems involve substantial capex. However, incremental approaches targeting ‘low-hanging fruit’ can yield significant savings with minimal investment.”
Key components of ventilation on-demand systems:
A method of controlling air delivery, such as a variable speed drive (VSD), variable output fan, dual-stage fan, dual-speed fan or dampers
A demand control signal, which is crucial for achieving energy savings, more so than the control method itself
A monitoring and reporting system, which allows for continuous performance tracking to ensure the system operates efficiently
There are three main methods used to implement ventilation on-demand in the Australian mining industry.
The first is manual control, which commonly sees an operator on the surface manually controlling underground fans using a supervisory control and data acquisition (SCADA) system.
The second method is schedule-based control, where the shift work schedule is entered into scheduling software that controls underground fans using a SCADA system.
Image: Smart-VOD
The third method of implementing VOD is automatic control, in which fans are controlled based on vehicles in a ventilation zone, which can include other factors such as air quality.
Twiss said ventilation energy costs make up a large portion of a mine’s total expenses and can significantly impact key financial metrics such as the all-in sustaining cost (AISC).
“A mid-sized gold mine deploying ventilation on-demand in the 10 most active areas on-site can reduce AISC by 10 per cent, significantly enhancing profitability,” he said.
A recent addition to the VOD arena is Smart-VOD’s VOD-as-a-service.
“In this case VOD can be delivered incrementally and without capex,” Twiss said. “VOD-as-a-service can be implemented in a single working area, or across several working areas in a mine.
“The system can additionally control primary ventilation fans for further savings, speed-up exhaust of blast gases and allow accelerated return to mining operations after a blast.
“Offering a detailed dashboard, Smart-VOD displays system status in real-time, along with savings and vehicle location information.”
By targeting ‘low-hanging fruit’ in ventilation on-demand implementation, miners can yield substantial energy savings without significant upfront costs.
“Smart-VOD offers an adaptable and scalable ventilation solution that enables mines to achieve immediate and impactful cost reductions, ultimately improving sustainability and profitability,” Twiss said.
This feature appeared in the September 2024 issue of Australian Mining.
