CHINA Shenhua Energy Co, the nation's biggest coal producer, started trial operation of a mine after investing 4.484 billion yuan (US$636 million) in the project.

The 20-million-metric-ton-a-year Bu'ertai mine in China's Inner Mongolia Autonomous Region is the world's largest by capacity, parent Shenhua Group Corp said in a statement on the Website of the State-owned Assets Supervision and Administration Commission.