(under subclass 29) Apparatus including means to prevent material which comprises the upper wall of an underground mine chamber from descending into the chamber.
SEE OR SEARCH THIS CLASS, SUBCLASS:
11, for a process of stabilizing underground mine structure, including supporting the mine roof.
31+, for a stepper type advance causing means which may also function as a walking roof support.
SEE OR SEARCH CLASS
248, Supports,
351+, for a prop or brace of general utility. 405, Hydraulic and Earth Engineering,
132+, for shaft and tunnel linings, per se, or combined with excavating means; and subclasses 288+ for temporary mine roof supports (props).
