The official Xinhua News Agency said Friday that the 26 men died in the mine in Lengshuijiang city in Hunan province happened when the brakes failed. It did not give any details on how that happened.
Xinhua said 19 men died immediately in the accident on Thursday and seven others later. Five men were injured but survived.
China's mines are the world's deadliest, although the closing of many small, dangerous mines has halved the average number of miners killed to about six a day in the first half of this year. Most accidents are blamed on failures to follow safety rules, including a lack of required ventilation or fire control equipment.