China has ordered the closure of all coal mines in southern Guangdong province and threatened to shutter up to one third of those around the country in a dramatic effort to address safety issues in its mining industry.

State-controlled media reported Friday that all 253 coal mines in Guangdong, which produces one-third of China’s exports, would be closed. Earlier this month, Guangdong ordered the closure of 112 coal mines after an accident at one killed 123 miners.