LANZHOU, April 26 (Xinhua) -- Nine people were buried in a deserted mine pit in northwest China's Gansu Province after it suddenly caved in on Wednesday morning.

The accident occurred at around 8:00 a.m. on Wednesday when 15 local farmers were foraging in a deserted stibium mine in Lintan county, Tibetan Autonomous Prefecture of Gannan, said Feng Wenge, vice head of the prefecture, on Thursday.

Six escaped but nine others were buried 20 to 40 meters underground, after 16,000 cubic meters of earth collapsed, say rescuers, who have not yet been able to establish contact with the miners.

Snowfall and the location of the pit, on a slope about 3,000 meters above sea level, is hindering rescue efforts.