TAIYUAN - The northern Chinese province of Shanxi will phase out collieries with annual production capacity of less than 600,000 metric tons by the end of 2020, local authorities said Monday.

The small mines are encouraged to merge, said the provincial government in a guideline on mergers and capacity cuts of coal mines.

Any single coal mining company must have an annual capacity of over 3 million tons by 2020. Open-pit coal mines must have annual production capacity of no less than 5 million tonnes after mergers.

Shanxi had more than 900 coal mines in operation or under construction at the end of 2017.