Kiruna, in the northernmost part of Sweden, is a remote region that is home to the iron ore pelletising plant at Svappavaara, which is owned and operated by LKAB. As an international high-tech minerals group the company
is 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 20ft x 140ft rotary iron ore pelletising 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,” said 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, supervisor for field
service and retrofits, the project required extensive preparation ahead of the installation. “LKAB brought in four cranes for both heavy lifting and precision positioning,” he said.

“Metso had to co-ordinate 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 178t) presented
some unique challenges, but Mr Johnston said the project provided a great educational, as well as technical
opportunity for Metso.

He said: “Typically, we would not need more than one field service engineer on site. 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,” said Bengt Andersson, who
had overall responsibility for the project. “There was zero
tolerance when the new bearing ring and 5.5m diameter
casing was 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 Mr 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 said. “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.”