An ambulance with survived workers leaves a railway tunnel in Lanzhou, capital of northwest China's Gansu Province, Dec. 14, 2012. Five construction workers who were buried in a tunnel that was under construction around 2:50 p.m. on Wednesday were rescued at 10:07 p.m. Friday. (Xinhua/Nie Jianjiang)

A trapped worker receives treatment on an ambulance at a railway tunnel in Lanzhou, capital of northwest China's Gansu Province, Dec. 14, 2012. Five construction workers who were buried in a tunnel that was under construction around 2:50 p.m. on Wednesday were rescued at 10:07 p.m. Friday. (Xinhua/Nie Jianjiang) 

An ambulance with survived workers leaves a railway tunnel in Lanzhou, capital of northwest China's Gansu Province, Dec. 14, 2012. Five construction workers who were buried in a tunnel that was under construction around 2:50 p.m. on Wednesday were rescued at 10:07 p.m. Friday. (Xinhua/Nie Jianjiang)

An ambulance with survived workers leaves a railway tunnel in Lanzhou, capital of northwest China's Gansu Province, Dec. 14, 2012. Five construction workers who were buried in a tunnel that was under construction around 2:50 p.m. on Wednesday were rescued at 10:07 p.m. Friday. (Xinhua/Nie Jianjiang)

A trapped worker receives treatment at a railway tunnel in Lanzhou, capital of northwest China's Gansu Province, Dec. 14, 2012. Five construction workers who were buried in a tunnel that was under construction around 2:50 p.m. on Wednesday were rescued at 10:07 p.m. Friday. (Xinhua/Nie Jianjiang)