Kazakhstan has warned ArcelorMittal, the world’s biggest steel company, that it could be forced to close one of its coal mines if it does not improve safety following an explosion last month that killed 30 people.

Vladimir Bozhko, head of Kazakhstan’s ministry of emergencies, has given ArcelorMittal one month to draw up a plan to introduce 41 safety reforms at the company’s Abaiskaya mine in central Kazakhstan, where the blast took place.