The collapse of the dam, holding back waste from iron ore production, in Liaoning province's Shiqiaozi village injured another 17, all of whom were in a stable condition.
Rescuers were searching for the missing as 10 bulldozers cleared mud and ore.
An 80-metre wide river of debris spilled across fields and into two low-lying villages, destroying cropland and 33 houses.
"The priority of our work is to look for the missing and resettle the homeless," Xinhua quoted Yang Jinfang, head of the publicity department in the nearby city of Anshan, as saying.
The dam, which Xinhua said belonged to the Dingyang Mining Co. Ltd, an iron ore producer, was supposed to be used to contain waste ore, but over the years there had been a buildup of water.
Authorities had sent inspectors to check four similar dams in the area, the report said.
China is frequently beset by industrial and environmental disasters.
Last week, 31 people were crushed in a landslide in central China, most of them trapped in a long-distance bus that was buried under an avalanche of boulders, earth and mud at the entrance to a railway tunnel being built near the site of the Three Gorges Dam.
Güncelleme Tarihi: 25 Kasım 2007, 14:48