It was May 2011, at a Gold Process Plant in proximity to Nelspruit and Barberton. One of the grinding SAG Ball Mills tripped on motor over-temperature. Fault finding on the Synchronous motor pointed to excitation failure, confirmed by a test of the exciter circuit.
We had a production problem - it would take more than a week to have this repaired. I found a solution and after sharing and agreement from the team, they fetched a spare 8 Ton Loco battery and charger from the mine entrance, matched copper area panel wiring, a circuit breaker, and a multi-meter. We selected the correct amount of cells to match the nameplate voltage/amps of the faulty equipment and arranged for it to be connected according to traced and marked panel wiring. It was done under my supervision with excellent team input.
In quick time the exciter was stripped off and ready for the OEM to collect. A few hours later, the Mill was started and ran like a clock with optimal excitation for the period awaiting delivery of the rewound exciter combination - actual was 5 days. The battery charger was kept connected in close proximity to the battery. Demand from the battery was only about 5 amps at 50 Volt = 250 Watt at optimal rheostat setting from the 800 Amp-Hour battery.
Outotec has signed a contract with a major copper producer for the design and supply of two grinding mills, for their concentrator in Southern Africa. The order value, over EUR10 million, has been booked in Outotecs 2017 fourth quarter order intake.
Mills ordered for the project are a semi autogenous mill, and a ball mill, with associated ancillaries and installation supervisory services. Equipment will be delivered at end of 2018, for commissioning in early 2019.
We are pleased that our customer could continue this project for which we did basic engineering already in the earlier phase. The equipment supply is expected to contribute to extending the life of mine significantly, notes Kimmo Kontola, head of Outotecs Minerals Processing business unit.Get in Touch with Mechanic