The Intrinsically Safe (IS) Proximity Box is located inside the Nautilus Explosion-Proof box (XP-Box). The circuit board inside the Proximity-Box contains all of the electronics required to provide the magnetic field for the two MF4 antennas. It also monitors the performance of the MF4 antennas and the cables that are connected to them.
 

The Proximity-Box electronics also monitor the status of the CM,. whether or not the cutter has been activated and the operating condition of the Coal-Buddy System. It contains two relays which are used to enable the Pump when the operator is a safe distance away from the CM.  The Pump will be shut down whenever the Continuous Miner gets too close to the Operator.