Abstract
An original underground wireless communication system was developed at Ikeshima coal mine. This system uses a UHF frequency band of 800 MHz wave and consists of a surface center station, underground stations and portable stations. Operatioanl tests indicated that this system was possible to communicate with high articulation of clear voice without influences of electric noise even in travelling and to keep high grade maintenance. Also this is can be used for emergency communication system and large effect in safety area is expected. These merits are going to introduce to overseas countries.
