IPC Main Group
E21C 41/00 Methods of underground or surface mining; Layouts therefor
Introduced: September 1968
Last revised: January 2006
Classification Context
- Section:
- FIXED CONSTRUCTIONS
- Class:
- EARTH OR ROCK DRILLING; MINING
- Subclass:
- MINING OR QUARRYING
Related Keywords
mining CLAY(S)mining GOLDmining METAL(S)mining ORESmining ROCK(S)quarrying SLATE(S)mining STONE(S)quarrying STONE(S)
3 direct subcodes
Child Classifications
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- E21C 41/16 Methods of underground mining; Layouts therefor
- E21C 41/26 Methods of surface mining; Layouts therefor
- E21C 41/32 Reclamation of surface-mined areas
Top Applicants
Top 10 applicants by patent filingsfor class E21, 2013–2023, worldwide · Source: EPO PATSTAT
- HALLIBURTON ENERGY SERVICES GROUP US 26,607
- PETROCHINA COMPANY 14,382
- SINOPEC (CHINA PETROCHEMICAL CORPORATION) 10,137
- CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 6,517
- BAKER HUGHES US 6,269
- SCHLUMBERGER TECHNOLOGY US 5,929
- SAUDI ARABIAN OIL COMPANY SA 5,880
- SOUTHWEST PETROLEUM UNIVERSITY 4,477
- CHINA UNIVERSITY OF MINING AND TECHNOLOGY 4,357
- SCHLUMBERGER TECHNOLOGY NL 4,219