Yuncheng, September 5 - As WIFI and smartphone had become essential in everyone's life, it’s rare to see them underground. Recently, Guotun Coal Mine of Heze Coal and Power Company, Shandong Energy Zibo Mining Group, has applied WIFI and smart phone at the mining faces. After the upgrade, the mining face is covered by 2.4G WIFI signal, allowing miners to access centralized control system via apps on their combust-proof smart phone and remotely control two conveyor belts. No longer is it necessary to run to the belt end which is more than 1000 meters away for overhaul. Now two people can finish the examination that used to require four people with one extra hour to spare.