Using RFID tags worn by personnel and detection units mounted on mining machines, Cat Detect Personnel identifies the presence of people on a longwall or near a continuous miner and transmits the location information to the machine control system. The control system then takes appropriate actions—such as inhibiting machine movement and providing warning signals—when necessary to avoid potentially unsafe situations.  

For longwall systems, each roof support is equipped with a detection device, which transmits data to the control system governing automated roof support advance. In the case of the Cat PMC-R electrohydraulic control system, personnel would delay advancing roof supports when people are detected in the affected area. The PMC-R controls have a bright 180° LED warning light and an acoustic alarm to indicate that roof support movement is pending.

Cat Detect Personnel for continuous miners is in development. The system detects the presence of people within a certain distance of the machine and in potentially unsafe locations. When appropriate, the system provides a warning signal to such personnel and the machine operator and inhibits machine movement until the area is cleared.

Each RFID tag worn by underground personnel incorporates a battery-powered transponder, essentially a transmitter and receiver. Each tag also has an identifier that is configurable with software to suit the needs of the mine. The tag could be configured, for example, to identify each person wearing a tag in the mine and/or to identify the wearer’s job title and specialized skills. That information could be transmitted to the longwall gate ends and to a mine office underground or on the surface for use in scheduling and assignment of personnel.

Both the tags and readers are small and intrinsically safe. The tags are easy to wear, and the readers are easy to install on equipment because no explosion-proof enclosures are needed. Both the tags and readers have very low power consumption. Most important, the system is highly accurate, and the longwall system—because each roof support controller acts as the local controller—has no delay, unlike systems that rely on communications via gate end controls to process data. The software is flexible and offers plug-and-play capability with the Cat PMC-R longwall controls.