Abstract: This invention provides mine equipment for sensing the advance of mobile equipment, particularly on longwall face conveyors the equipment comprises two mine roof supports provided with sensor means for sensing relative movement between the associated roof supports and an elongate bar component secured to the conveyor and extending between the two supports in a direction rearwardly of the conveyor. The elongate component is magnetized so that a magnetic field is induced adjacent thereto, the induced magnetic field intensity varying longitudinally of the elongate component.

Abstract: A signal derived from means, e.g. a gyroscope, mounted on the machine is used to guide a shearer drum along a straight path, the shearer being mounted on an underframe including two pivotally connected parts.

Abstract: Mine equipment for measuring conveyor advance includes two roof support assemblies and control means to ensure each of the assemblies can be advanced only when the other assembly is anchored. The two assemblies are linked by a transducer which senses movement of one of the assemblies relative to the other assembly.

Abstract: In controlling advance of an armoured conveyor in an underground mine, detector means detect the advance of different conveyor sections and control means control current and/or subsequent advances of the conveyor in relation to the detected advances.