Abstract: A mining system comprises a laterally deflectable segmented conveyor extending longitudinally along a longitudinal face from which material is to be cut, a mining machine displaceable longitudinally along the conveyor and engageable with the face to cut material therefrom and deposit in the conveyor, and a longitudinal succession of support frames each having a respective actuator connected to a respective segment of the conveyor and each also having a respective a respective retractile roof-engaging flap. The process of this invention comprises bracing the frames and conveyor in a safety zone immediately adjacent the mining machine against the roof with their flaps retracted. The machine is advanced in the safety zone while cutting the face in the safety zone, and the flaps of the frames in a zone immediately downstream of the safety zone are sequentially retracted and the flaps of the frames in a zone upstream of the safety zone are sequentially advanced.

Abstract: An adustable cap unit for a mine support frame including a main cap, an adjustable cap connected to the main cap with a hinge-type connection, an adjusting cylinder mechanism extending within the widths of the main cap and the adjustable cap, and a guide for guiding a portion of the adjusting cylinder mechanism in a restrictive manner. The adjusting cylinder mechanism is provided either in the main cap or in the adjustable cap and an end portion of the adjusting cylinder mechanism is hinged to a bearing member provided at the bottom edges of the main cap or the adjustable cap adjacent the hinge-type connection. The adjustable cap unit can be used in extremely small seam thicknesses of as little as approximately 500 mm, while the contact pressure available at the front end of the adjustable cap is sufficient.

Abstract: A hydraulic control arrangement for providing synchronism of a return cylinder between a face conveyor and a support, has a pushing cylinder which displaces the support transverse to a face, a control valve, a control cylinder influencing loading of the pushing cylinder via the control valve, and a control column provided between the return cylinder and the control cylinder and composed of a working fluid.

Abstract: A control arrangement for a hydraulically operated mine roof support having first and second consumers which require smaller and larger amount of the working medium per time unit, respectively, has first control elements for the first consumers and second control elements for the second consumers. The first control elements include a first bundle of hoses having a small inner diameter and arranged to select and apply pressure to the first consumers directly from a neighboring mine roof support. The second control elements include a second bundle of hoses with a small inner diameter, main control valves indirectly remotely controlled through the second bundle of hoses and arranged to select the second consumers, and conduits extending between the second consumers and the main control valves and arranged to apply pressure to the former. The conduits have an inner diameter which exceeds that of the hoses of the first and second bundles.

Abstract: A valve arrangement for operating a walking mine roof support so as to automatically move the props of the mine roof support first to a collapsed position and advancing the mine roof support and only thereafter moving the props to their extended position and in which control of the valve arrangement is carried out with the pressure fluid which acts on the members of the walking mine roof support.