RUC Mining launches regenerative mine winder energy storage system

Underground mining contractor RUC Mining has launched a regenerative energy storage solution for mine shaft hoists or winders.

Winders are heavy machines used to raise and lower minerals and materials in a mine shaft, with energy expended especially as the hoists raise materials and people to the surface.

RUC Mining’s innovation is to capture and store energy generated on the way down, and then used to power the upward journey.

When hoisting a load up a mine shaft, electric motors consume energy, but when travelling downwards, they have the potential to become generators.

RUC electrical manager Greg Bell and his team chose strategic partners Rockwell Automation and Energy Power Systems Australia (EPSA) to create what they believe to be the world’s first regenerative energy storage solution for underground mine winders, allowing the machines to run totally on their own stored energy, rather than requiring a separate diesel generator.

In its first application in an Australian mine, RUC installed its RUCShaw 512 single-drum winder, which is powered by 710 kW drives, has a hoist capacity of five metres per second, with 12-tonne line pull, and operates with a design depth of 1,600m.

Bell said: “Most mine hoists use a brake resistor pack with a cooling fan to deal with the heat generated. But these packs create a single point of failure, and are application-specific, so they need recalculation if a variation in brake power is required.

“Instead, we proposed for the generating power to be supplied back onto the incoming supply bus, to be absorbed by system loads.

For the system Rockwell Automation provided Active-Front-End (AFE) Powerflex 755TR regenerative variable speed drives, Low Voltage Motor Control Centres, and GuardLogix controllers, as well as software for application management and to give a complete real-time overview of operations.

The battery selected to store regenerative energy was a Cat PGS 1260 Battery Energy Storage System (BESS) supplied by EPSA, which provided added redundancy through its parallel inverter and battery stack architecture.

Berll said: “We have one operational project where we have implemented this solution with two hoist drives, and we are looking into incorporating this into future projects.

“We also see potential for this solution to be rolled out on new and existing mine shafts internationally.”

By reducing the amount of diesel power generation RUC has estimated that in their initial installation, over a 24 month period, the regenerative energy storage solution will achieve:

• An estimated reduction in diesel consumption of 1,427 kilolitres (which saves approximately $2 million)
• A reduction of 3.85 tonnes of CO2 output (that’s approximately equal to travelling 12,700km in a petrol car)
• And an approximate 42 percent reduction in greenhouse gas emissions from power generation.

“In addition to these strong sustainability benefits, the regenerative energy storage solution also reduces daily operating costs, reduces plant operating hours and maintenance requirements, and provides an additional level of redundancy to the power system that was not available in passive components such as load banks.”

Picture: Rockwell Automation/RUC Mining