At the Erzberg in the city of Eisenerz in Styria, Austria, mining operator VA Erzberg GmbH produces about 2.7 million tonnes of fine ore per year from an extraction volume of roughly 11 million tonnes. That makes Erzberg the largest iron ore surface mine in central Europe. A fully automated fine ore storage facility has been operating there since 2014. One of its key components is a reclaimer supplied by SBM Mineral Processing, an Austrian specialist in processing technology. WEG’s subsidiary Watt Drive provided the drive technology for the numerous conveyors of this advanced bridge bucket-wheel reclaimer.
SBM Mineral Processing (SBM), with headquarters in Oberweis (Austria), is part of the international MFL Group. SBM specialises in the development and production of concrete mixing plants as well as processing and conveying systems for the natural stone and recycling industries. Their Stationary Systems business area designs and builds high-performance solutions for the natural stone sector, the sand and gravel sector, building material recyclers and other industrial sectors. The application areas include crushing and processing of minerals, ores and coal, cost-effective transfer of processed bulk materials, and recycling of used building materials.
SBM’s new high-efficiency reclaimer is the core component of the fully automated Erzberg fine ore storage facility officially opened in 2014. The new reclaimer has significant advantages over the previous storage method of tipping fine ore from heavy-duty trucks and further transport by wheel loaders, including a distinct improvement in ore quality thanks to better mixing, lower cost due to elimination of a heavy-duty truck and a wheel loader, and substantial reduction of CO2 emissions by nearly 1,000 tonnes per year.
High availability is a key factor
The SBM reclaimer is specifically designed for the raw materials industry. With an overall width of about 65 m and a capacity of 1,100 t/h, it is a true giant in the processing technology world. Designed to operate reliably over a temperature range of -30C° to +40C°, it shrugs off extreme conditions such as snow, ice and high temperatures. Another special feature is the high storage capacity of 35,000 m³ per pile, with two piles handled simultaneously in a dynamic process. The first pile contains processed material with a particle size of 0 to 8 mm and is built up layer by layer using a reversible distribution belt. The second pile is processed by the reclaimer using a bucket wheel with a diameter of 9 m, which removes material automatically or semi-automatically and transports it to the railcar loading station over conveyor belts.
Reliable operation of the complex conveyor systems is crucial for reclaimer productivity. Failure of one or more conveyor belts can lead to total production stoppage in the worst case, with costly consequences. Ruggedness, low maintenance and reliable operation are therefore key requirements for the geared motors of the drive systems. In the harsh environment of surface mining, they must be able to withstand high dust loads as well as temperature swings and high humidity.
Marcus Altenreiter, Maintenance Manager at VA Erzberg, comments: “We already had good experience with gear units from Watt Drive in our processing plants. A significant success factor for the reclaimer project was that we could put this experience to good use in the layout and dimensioning of the new unit, and Watt Drive did a very good job of implementing our proposals.”