Two miners work at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

Two miners push an ore cart at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

A minter works at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

Two miners move an ore cart at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

A miner arranges the waterpipe at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

Two miners sort out ores as others wait behind due to the small work space at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

Two miners push an ore cart at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

Two miners push a cart at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

Miners push a cart at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

A miner loads a cart with ores at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

Miners with head lamps make way for a cart at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

A miner loads a cart with ores at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

Two miners push a cart at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)

Two miners prepares a cart of ores for elevation at a gold mine in Linqu County, Weifang, east China's Shandong Province, Nov. 6, 2013. Over 120 miners work here at depths from 60 to 120 meters underground. (Xinhua/Sun Shubao)