FMR Investments operates three major mining plants in Australia. One of them, Greenfield’s Mill, is located in the historically significant Western Australian Goldfields. This mill has provided a first-class toll milling facility to the gold industry for over twenty years.
Greenfield’s Mill features three ball mills, and an optimised circuit so that the needs of FMR Investment’s clients can be catered to in order to maximise gold recovery in their global-scale Tier-1 projects. The plant can treat up to one million tonnes per annum of ore product with its crushing and mill circuits.
When it comes to processing, stockpile ore on the Greenfield’s Mill initially passes through a three-stage crushing circuit. Feed from the crushers is then graded with a screen that removes undersized material from the circuit. The product produced, sized between six and eight millimetres, is then transferred to one of three 1000 tonne mill feed bins, which classifies the heap leach required of the product, in order to leach the gold from the ore. In this mill circuit, the three ball mills are used – which range from 500 kW up to 1300 kW.
FMR Investments recently experienced an issue with their existing motor that operated their primary 1300 kW ball mill. The motor had failed while in service, bringing operations to a fast halt. This was critical because a stopped mill circuit costs the business around $40,000 (AUD) per hour. FMR Investments decided to hire another motor for a period of approximately eight months, and at a cost of $1,000 (AUD) a day, in order to continue operations while they investigated a new motor option and waited for its installation.
In the interim FMR Investments had consulted with ABB Australia, who had team members came on site to assist with identifying motor options and key benefits. It was determined that an ABB NMK slip-ring modular motor would be best to ensure sustained uptime and increase operational efficiency on the Greenfield’s Mill plant site.
New ABB 1300 kW slip-ring motor 
The ABB 1300 kW slip-ring motor installed onsite at Greenfield’s Mill gold processing plant
NMK slip-ring motors are used in applications requiring high starting torque or low starting current. They are especially suitable for heavy load inertia applications like mill drives or situations where network conditions are weak and are made of materials that can withstand these conditions ensuring low vibration levels to help extend the motor lifetime. On the Greenfield’s Mill plant, they would be especially helpful thanks to new features like inspection windows that allow maintenance supervisors to see inside the slip ring chamber and verify everything’s running correctly.
There’s also a differential pressure switch inside the slip ring chamber which supports condition monitoring, and a separate total enclosed slip ring chamber box to prevent the brush carbon dust from entering the machine’s frame, thus removing the possibility of stator and rotor winding contamination. An independent slip ring chamber ventilation circuit ensures complete and even cooling air to each slip ring for more proficient performance. With additional safety options like alarms and automated notifications, concerns of downtime are erased.
ABB has been an industry leading manufacturer of electric motors, with more than 125 years of experience in applying medium and high voltage AC machines to virtually all industries. FMR Investments didn’t hesitate to work with ABB Australia to support their needs with purchasing and installing their NMK slip-ring motor for this application, given the long-standing assistance they always receive from the team which spans across eight years.
“ABB always delivers on their promises. The ABB name in motor manufacturing makes all the difference, and that’s why we’ll look to replace more existing motors with ABB products in the future,” said John Taaffe, Electrical Supervisor at FMR Investments.
FMR Investments is now looking to install another ABB motor on their Greenfield’s Mill plant, to operate their secondary ball mill.
ABB (ABBN: SIX Swiss Ex) is a leading global technology company that energizes the transformation of society and industry to achieve a more productive, sustainable future. By connecting software to its electrification, robotics, automation and motion portfolio, ABB pushes the boundaries of technology to drive performance to new levels. With a history of excellence stretching back more than 130 years, ABB’s success is driven by about 110,000 talented employees in over 100 countries. www.abb.com
