Lafarge has spent $646,000 replacing the hoop of its furnace at its cement factory in Bouc Bel Air, southern France.
The 70 tonne hoop is a central mechanical part of the oven to cook of material.
It is changed on average every 60 years. The work was carried out by Cofely Endel of the GDF Suez group, and required a three week furnace shut down.
The Bouc Bel Air factory can produce 800,000 tonnes a year.