Workers celebrate the holing-through at the construction site of the Lianyuanshan Tunnel in Liuyang, central China's Hunan Province, June 21, 2017. The tunnel, a key part of a over 1,800 km coal transport railway line connecting north China's Inner Mongolia Autonomous Region with Ji'an City in east China's Jiangxi Province, was successfully holed through on Wednesday. (Xinhua/Li Ga)