Expert on gold mine explosion in China: Unknown situation may bring more challenges
It's been 9 days since an explosion tore through a gold mine in Shandong Province, leaving 22 men missing. Rescuers are racing to free miners trapped underground. Crews suddenly got signs of life on Sunday night. Rescuers continue to drill holes to the tunnel. They plan to drill six holes, including one rescue hole and five contact holes. Professor Li Xuwei from University of Mining and Technology shares his analysis on the rescue work.