Abstract: A mine safety system for use with a direct current power supply delivering power via a pair of conductors to the direct current load components of mining apparatus which includes a conductive frame electrically isolated from ground and at least one of the conductors. In the safety system, an alternating current generator transmits a predetermined frequency signal over the pair of conductors to the mining apparatus. A filter which passes the predetermined frequency signal is disposed at the mining apparatus in a shunt circuit with the load components, the filter thereby being connected to the generator.

Abstract: A coal-gathering assembly for a continuous miner in which a platform is disposed behind a rotatable cutter, and a coal-transporting conveyor is located adjacent the platform for delivering coal rearwardly of the miner. The assembly includes a base plate rotatively mounted on the platform on each side of the coal-transporting conveyor. A plurality of bars are carried by each base plate, each bar extending across its associated base plate intermediate the rotative axis of the base plate and the base plate periphery. Each bar has one end adjacent the next angularly adjacent bar and has the other end extending beyond the base plate periphery. Each angularly adjacent pair of bars provide a substantially inwardly closed pocket. More particularly, each bar extends across the base place and is spaced from and intermediate the rotative axis and the base plate periphery, and extends substantially transverse to a radial line passed through the rotative axis and intermediate the ends of the bar.