BEIJING (Reuters) – A train carrying bauxite owned by China’s biggest state-controlled aluminium producer, Chinalco, derailed on Wednesday night, local government said in a statement on the Twitter-like Weibo.

Six people are missing after the accident in Gongyi city in the central province of Henan, including four train staff and two villagers living near the rail line, the statement on Thursday said.

A spokesman for Chinalco, known formally as Aluminium Corp of China, told Reuters that rescue work is continuing and the company is investigating the reason for the derailment.

Bauxite is the raw material for aluminium.

The most-active aluminium futures on the Shanghai Futures Exchange opened down 0.1 percent at 13,835 yuan ($2,060.22) a tonne on Thursday.