There have been more arson attacks at the New Caledonian mining site at Kouaoua.
Local media reports say a fire overnight Monday burnt a stretch of the conveyor belt which feeds nickel ore to the coast for shipping to the SLN smelter in Noumea.
The reports say there were two more fires last week despite the deployment of about 20 police to the area.
Late last month, six people were charged over arson attacks which have numbered about 20 this year.
The Kouaoua site, which provides more than a third of SLN's ore, was closed for nearly three months this year as a result of two blockades set up by a local group opposed to expanded mining.
The French High Commission said Kouaoua residents and SLN employees were legitimately exasperated in the face of actions which nothing could justify.