299 / | HD | MINING OR IN SITU DISINTEGRATION OF HARD MATERIAL |
29 | DF | HARD MATERIAL DISINTEGRATING MACHINES {17} |
42 | DF | .~ Sidewall-working (e.g., drum-type cutter) {4} |
43 | DF | .~.~ With material-handling means {3} |
44 | .~.~.~ Undercutting, dislodging and conveying |