The seven minors include four daughters of a local villager, aged between eight months to six years, state-run Xinhua news agency reported.
The 64 people, 48 male and 16 female, have gone missing after more than 15 dormitories and three houses owned by Wuzhou mining company in Shanyang County were buried under about 1 million cubic metres of mud in the mountainous county of Shanyang just after midnight Wednesday.
Earlier reports had put the number of missing at 65 as one person's name was recorded twice, said Kang Mingliang, a spokesperson for the government of Shanyang County.
After the landslide, 10 people managed to escape on their own and four others were dug out by rescuers who were admitted to a hospital where their condition was stated to be stable.
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More than 700 police, firefighters, mining rescuers and paramedics are still searching for the missing persons.
Nearby residents have been evacuated.
China, world's largest producer of coal, is grappling to find ways to improve standards in the mining sector, where regulations are often violated.
Accidents in Chinese coal mines killed about 930 people last year.