Friday's decree also limits mining holdings to three concessions per company, and calls for revoking all their remaining concessions without compensation.

A top mining ministry official said the ministry will call affected companies for talks next week, and plan the suspension and revoking of concessions.

"We have flexibility to apply the decree and interpret it in some issues, but the suspension and holdings reduction is something we can't undo," said the official, who asked not to be named because he was not allowed to speak publicly.