A total of 20 workers died in two separate accidents just kilometres (miles) apart and within 36 hours of each other in northern China, state media said Tuesday.
Seventeen were killed in an explosives accident in Yu county, Hebei province on Monday, after three died in nearby Chicheng county during the weekend, Xinhua news agency reported.
Xinhua did not give details of the Chicheng accident but the two incidents did not appear to be related.
Local authorities have closed all mines in the area while their safety precautions are checked.
China's mines are regarded as the world's most dangerous with nearly 6,000 workers dying in the industry last year, according to official figures.
Labor rights groups, such as the Hong Kong-based China Labour Bulletin, say the real number of mining deaths could be as high as 20,000 each year.
