(under the class definition) Apparatus comprising the structure or arrangement of an opening into the earth which is utilized to recover a valuable material.
SEE OR SEARCH THIS CLASS, SUBCLASS:
11, for a mine layout involving a process of stabilizing underground structure.
12, for a mine layout involving a process relating to mine safety.
SEE OR SEARCH CLASS
405, Hydraulic and Earth Engineering, 132+, for the structure of a shaft or tunnel, per se, including means to support shaft and tunnel walls, etc.
454, Ventilation,
168+, for mine structure relating to providing proper air supply and circulation for workers in a mine.
