Kiruna, a remote region in the northernmost part of Sweden, is home to the iron ore pelletizing plant at Svappavaara, owned and operated by LKAB. The company is an international high-tech minerals group, one of the world’s leading producers of upgraded iron ore products for the steel industry and a growing supplier of industrial minerals products.
When LKAB needed to replace a section of kiln shell, riding ring, kiln support rollers and associated bearings on a 20 x 140' rotary iron ore pelletizing kiln, they called on their 40-year working relationship with Metso to plan and execute the project.
"This is one of the biggest repair jobs ever carried out at Svappavaara," says Petrus Esberg, maintenance engineer for LKAB. 'The need to replace the kiln shell section has been apparent for several years due to cracks in the shell and stress cracking of the riding ring." The situation was constantly monitored, and a slowdown in the market finally afforded LKAB the opportunity to make the repairs.According to Metso’s Chris Johnston, a supervisor for field service and retrofits, the project required extensive preparation prior to installation. "LKAB brought in four cranes for both heavy lifting and precision positioning," he says. "Metso had to coordinate multiple manufacturers and subcontractors for all the parts and replacement items."
The sheer size of the kiln and weight of the parts - the old shell section and riding ring weighed 178 tonnes - presented some unusual challenges, but Johnston said that the project provided educational and technical opportunities for Metso. "Typically, we would not need more than one field service engineer on site," he explains. "But this was such an unusual mechanical challenge that we brought in six more engineers so they could learn from the experience."
This attention to detail was well-received by LKAB. "It was really a precision job," says Bengt Andersson, who had overall responsibility for the project. "There was zero tolerance when the new bearing ring and 5.5 meter [~18'] diameter casing [were] installed. Because of everyone’s commitment to the project, we avoided any major disturbances."
LKAB was also pleased with how Metso handled the various sub-contractors. According to Johnston, the cooperative effort between Metso’s offices in Danville and Kiruna was key to the successful completion of the work. Bengt Hedlin did a great job in the bid process and awarding of contracts,” he says. “With several manufacturers supplying so many different components, there could have been a lot of problems. But we handled it to the complete satisfaction of the customer."