A whole mine, computer-controlled communication and monitoring system for both normal and emergency use is installed and operating in the U.S. Steel Robena Mine complex near Uniontown, Pa. Portions of the system, including the coaxial cable and the key underground and surf ace phones, have been operating for over a year and a half. During this time the basic concept has been modified and new line amplifiers with directional switches have been developed to eliminate some problems in implementing the loopback feature. The quality of the audio and the availability of the system have been outstanding. Since early summer almost all subsystems have been completed. The experience with the telephone system itself , the pocket-pager call alert , section wireless radio, hoistphone, television, environmental monitoring, control and monitoring of equipment, voice downlink/code uplink post disaster communications, post disaster through-the-earth monitoring, and the system center failure diagnostic routines are reviewed.