Improving Energy Efficiency
Sibanye-Stillwater, a multinational mining and metals processor, engaged Energy Drive to improve and accelerate the energy efficiency of their mine ventilation systems. Energy Drive focused first on the large surface ventilation fans used in two of Sibanye’s gold mines in South Africa. Ventilation in underground mining is critical but uses a lot of energy.
“Due to health and safety, there’s always at least one fan fully operational and another in standby in case there’s a failure,” James explains. “We installed and optimized VFDs (variable-frequency drives) on the motors of both fans and then turned (the speeds of) them down while running them together.”
Significant Sustainability Benefits
Using Rockwell Automation PowerFlex® 6000T VFDs to control and reduce the fan speeds, Energy Drive delivered an average of 62% in energy savings in the first shaft and 48% in the second. The two upgraded shafts have been operational for nearly a year, and they’ll soon commission a third shaft. James projects the three upgrades will deliver an energy savings of about 360 gigawatts (GWh) over the term of the contract.
That’s equal to removing, “5000 homes in South Africa from the grid every month. More importantly, measuring on actualizing sustainability, it will save 379,000 tons of carbon over the period,” James adds. The optimized systems have also significantly reduced water and coal consumption.
Helping Protect Miner Safety
Best of all, Energy Drive electronically controls the upgraded systems from the surface. “All of our systems are monitored 24/7 with pre-set alerts on key conditions,” James says. “Now that we’re running both (fans), if one fails our system automatically ramps up the other so that we never ever put the health and safety of the miners underground at risk.”
Another benefit of monitoring and running both fans is improved equipment performance and maintenance.
James credits the project’s overall success to an “extremely collaborative” client “committed to using technology to improve operational performance and safety, and Rockwell Automation’s technological excellence.”
Read more about how Energy Drive, Rockwell Automation and Sibanye-Stillwater collaborated to realize significant energy savings and find additional project details here.