There has been another fire at the New Caledonian mining site at Kouaoua.
Local media reports said a stretch of the conveyor belt which feeds nickel ore to the coast for shipping to the SLN smelter in Noumea has been burnt.
An investigation has been opened.
There have been more than 20 arson attacks on the belt system in the past two years.
The Kouaoua site, which provides more than a third of SLN's ore, was closed for nearly three months last year as a result of two blockades set up by a local group opposed to expanded mining.
The disputes were settled and the site became operational while SLN was being hit by strikes at its other mines.
SLN, which has been running at a loss, last month secured the government's consent to export four million tonnes of nickel ore a year for ten years as part of its restructure.