The cable of a rail carriage taking workers into the mine in Gansu province snapped, sending the 34 miners plummeting into the pit, Xinhua news agency reported.
The injured have been transported to hospital, including three who were in a serious condition, it said.
Officials at the Baiyin city work safety administration, which oversees the Qusheng mine, refused to comment when contacted by AFP.
China is the world's biggest consumer of coal, relying on the fossil fuel for 70 percent of its growing energy needs.
But its mines are among the deadliest in the world because of lax regulation, corruption and inefficiency. Accidents are common because safety is often neglected by bosses seeking quick profits.
Tuesday's accident followed a gas explosion at a colliery in the southwest Sichuan province last month which killed 43 miners.
According to the latest official figures, 1,973 people died in coal mining accidents in China in 2011, a 19 percent fall on the previous year.
But labour rights groups say the actual death toll is likely to be much higher, partly due to under-reporting of accidents as mine bosses seek to limit their economic losses and avoid punishment.
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In your higher than Himalayas and deeper than the sea, more than 2000 people die each year in coal mines. And most of them are forced to work there.
Labor laws are just in efficient every where.Who knows how many victims are of such incidents, reported and unreported, in Pakistan ?
we want less aid from china this time. pak-china friendship zindabad.