IPC Main Group
E21D 13/00 Large underground chambers; Methods or apparatus for making them
Introduced: September 1968
Last revised: January 2006
Classification Context
- Section:
- FIXED CONSTRUCTIONS
- Class:
- EARTH OR ROCK DRILLING; MINING
- Subclass:
- SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
2 direct subcodes
Child Classifications
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- E21D 13/02 Methods
- E21D 13/04 Special equipment; Accessories