E21D SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS (soil-conditioning or soil-stabilising materials C09K17/00; drilling or cutting machines for mining or quarrying E21C; safety devices, transport, rescue, ventilation or drainage E21F)
Description
Covers the construction, design, and engineering of vertical and horizontal underground excavations for mining, transportation, utilities, and storage purposes. Includes shafts (vertical access routes), tunnels (horizontal or inclined passages), galleries (larger horizontal chambers), and spacious underground voids for coal mines, metal mines, civil engineering projects, and subsurface infrastructure. Excludes general drilling and boring techniques classified under E21B, and addresses structural support systems, ventilation arrangements, and access provisions specific to these large-scale underground structures.
14 direct subcodes
Child Classifications
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- E21D 1/00 Sinking shafts
- E21D 11/00 Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling (E21D15/00 - E21D23/00 take precedence; specially for shafts E21D5/00; ; lining pressure water galleries, linings therefor E02B9/06)
- E21D 13/00 Large underground chambers; Methods or apparatus for making them (lining E21D11/00)
- E21D 15/00 Props (in the building art E04G25/00); Chocks
- E21D 17/00 Caps for supporting mine roofs
- E21D 19/00 Provisional protective covers for working space (E21D9/06, E21D23/00 take precedence)
- E21D 20/00 Setting anchoring-bolts (anchoring bolts for shafts, tunnels or galleries E21D21/00; means for anchoring structural elements or bulkheads specially adapted to foundation engineering E02D5/74; dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose F16B13/00)
- E21D 21/00 Anchoring-bolts for roof, floor , or shaft-lining protection (; dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose F16B13/00 )
- E21D 23/00 Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor ( shifting of mine conveyors at the working face E21F13/08)
- E21D 3/00 Raising shafts, i.e. working upwards from the bottom
- E21D 5/00 Lining shafts; Linings therefor (E21D11/00 takes precedence )
- E21D 7/00 Shaft equipment, e.g. timbering within the shaft
- E21D 8/00 Shafts not provided for in groups E21D1/00 - E21D7/00
- E21D 9/00 Tunnels or galleries, with or without linings; Methods or apparatus for making thereof (E02D29/045, E02D29/063 take precedence; linings per se E21D11/00); Layout of tunnels or galleries
Top Applicants
Top 10 applicants by patent filingsfor class E21, 2013–2023, worldwide · Source: EPO PATSTAT
- HALLIBURTON ENERGY SERVICES GROUP US 27,652
- SAUDI ARABIAN OIL COMPANY SA 7,755
- PETROCHINA COMPANY 7,025
- BAKER HUGHES US 6,589
- SCHLUMBERGER TECHNOLOGY US 6,151
- SINOPEC (CHINA PETROCHEMICAL CORPORATION) 4,443
- SCHLUMBERGER TECHNOLOGY NL 4,255
- CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 3,991
- SERVICES PETROLIERS SCHLUMBERGER FR 3,300
- SCHLUMBERGER CANADA CA 3,086