Repairs Begin at Tilden Mine

Cliffs Natural Resources, Michigan Operations, has started a major repair project at the Tilden Mine.  The mine is replacing a riding ring and a section of shell on one of its two rotary pelletizing kilns.  

The two kilns that operate at Tilden are unique to the iron ore business and are among the largest diameter kilns in the world. The repair of the kiln is necessary for maintaining efficiency and is a part of regularly scheduled maintenance at Tilden for 2012.  


Cliffs indicates that the kiln riding ring being replaced has an outside diameter of 29 feet, a width of 40 inches, is 20 inches thick and weighs approximately 124 tons. The project will include the replacement of the kiln riding ring, a section of kiln shell, two carrying rollers and one kiln thrust roller.  The Company said the entire cost of the project is estimated at $6.7 million.  


“This is a significant investment by Cliffs for the continued sustainability of the Tilden Mine,” said James Kochevar, interim general manager, Michigan Operations for Cliffs.  “Production will be interrupted on the kiln; however, the riding ring replacement is necessary in order for Cliffs to continue to provide a reliable operation well into the future.”


The repair is similar to the riding ring and kiln shell replacement that took place in June 2010 at Tilden.  The 2010 repair took place on the south side of the pellet plant and utilized a 1,000 ton crawler crane to remove and replace the ring and shell.  

The Company said that due to logistical challenges, two smaller cranes will be used for this year’s repair which occurs on the north side of the plant.  The cranes being used will be a 600 ton crawler crane and an 800-ton truck crane.  A section of the Tilden pellet plant roof will be removed to gain access to the kiln.  


The kiln shell was delivered by semi truck in December and the riding ring was delivered as a critical spare in 2009.  The two cranes arrived on the Tilden property in sections and were assembled on site.  Work on the project began this week and will last approximately 42 days.