having protective means, e.g. shields, for preventing or impeding entry of loose material into the working space or support

Full Title

Mine roof supports for step-by-step movement, e.g. in combination with provisions for shifting of conveyors, mining machines or guides therefor > having protective means, e.g. shields, for preventing or impeding entry of loose material into the working space or support

Classification Context

Section:

FIXED CONSTRUCTIONS

Class:

EARTH OR ROCK DRILLING; MINING

Subclass:

SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS