IPC Main Group
E21D 8/00 Shafts not provided for in groups
Introduced: January 2006
Classification Context
- Section:
- FIXED CONSTRUCTIONS
- Class:
- EARTH OR ROCK DRILLING; MINING
- Subclass:
- SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D 8/00 Introduced: January 2006