Under new regulations, mixed-type rare earth mines must have a minimum annual production capacity of 20,000 tonnes and smelting companies must ensure an annual output of at least 2,000 tonnes, according to the Ministry of Industry and Information Technology (MIIT).

The change could mean as many as one-third of the country's 23 rare earths mines and about half of the 99 smelting companies would be closed, according to director of the ministry's rare earths office Jia Yinsong, quoted in the China Daily newspaper.