African gold mine digs deep for safe and reliable power supply

African gold mine digs deep for safe and reliable power supply

ABB has worked closely with its engineering partner on a complex African mining project to upgrade key electrical infrastructure. The project, a partnership between ABB Electrification and original equipment manufacturer (OEM), Power Plant Electrical (PPE) Technologies, has enhanced efficiency and safety for one of the largest and most productive gold mines in Ghana, which extracts up to one million tons of ore per year.

The electrical infrastructure needed upgrading to support the reticulation system, the network of cables, switchgear, and associated equipment to efficiently distribute electrical power throughout the mine. To deliver a robust, reliable, and safe electrical supply, ABB provided PPE Technologies with products for PPE’s switchgear solution. This included 38 ABB Relion® protection relays, over 230 11kV VD4/P vacuum circuit breakers at 2 500A and 1 250A, as well as 400A VSC/P vacuum contactor motor starters.

As a result of the mine’s production schedule, the solution had to be installed within a tight timeframe to prevent costly disruptions to operations. Working with PPE Technologies, ABB jointly defined a production and delivery schedule that allowed the solution to be delivered to the end customer in only six weeks.

“The client was looking for a reliable and cost-effective solution that could be implemented in line with a tight project schedule,” said Sizwe Nkosi, Product Marketing Specialist at ABB. “Working closely with PPE Technologies, we were able to overhaul the mine’s electrical infrastructure within an extremely short timeframe. More importantly, the project has not only ensured power system reliability but created a safer working environment for the mine’s personnel, as the new Relion relays protect against a wide range of electrical faults, such as arc faults, overloads or short circuits.”

With depths of up to 1,500m, careful planning and execution were required to transport equipment and materials through deep and confined spaces in the mine. Additionally, high temperatures within the mine, of up to 55 degrees Celsius, presented another challenge. “The heat generated from mining activities and machinery required specialized equipment and materials capable of withstanding extreme conditions,” explains Nkosi.

To cope with these demands, the Relion protection relays were coated with an additional layer of protection, conformal coating, which maximizes resistance to moisture and corrosive agents, and is designed to protect electronic circuits in demanding environmental conditions. ABB also selected equipment with the correct IP rating for the mine's environment.

To keep the mine operating 24/7, it is vital there is no loss in communication with this critical infrastructure. The Relion relays’ redundant communication abilities allow the communication network to continue to operate even in the event that one of the network cables is damaged. This ensures continuous operation and visibility of the plant's reticulation network.

Using Modbus communication protocol, the power system gathers data from the Relion protection relays, which enables comprehensive monitoring, analysis and control. This makes proactive maintenance and remote monitoring of the electrical system in the existing Supervisory Control and Data Acquisition system (SCADA) possible, allowing for early detection of potential issues and efficient troubleshooting.

Importantly, the switchgear solution offers flexibility and scalability for future expansions or modifications. The infrastructure can now accommodate new equipment installations to meet evolving power demands, providing a foundation for future growth without significant disruptions or costly overhauls.

Nkosi adds: “This has been a hugely successful collaborative project, delivering more than 13 medium-voltage switchgear that integrates seamlessly with the existing electrical infrastructure across 50 levels in a tough and demanding environment. It is a great example of how ABB works with strategic partners to deliver world-leading electrification solutions.”

“Our company has worked with ABB products for over 20 years,” highlights Mitch McAllister, Managing Director of PPE Technologies. "The gold mine operator is very pleased with the solution and looks forward to the entire underground reticulation network being retrofitted with ABB solutions.”

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