Methods of underground mining (winning machines therefor E21C25/00 - E21C39/00); Layouts therefor

Full Title

Methods of underground or surface mining (E21C45/00 takes precedence); Layouts therefor (for peat E21C49/00) > Methods of underground mining (winning machines therefor E21C25/00 - E21C39/00); Layouts therefor

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Child Classifications

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E21C 41/18 for brown or hard coal
E21C 41/20 for rock salt or potash salt
E21C 41/22 for ores, e.g. mining placers
E21C 41/24 for oil-bearing deposits

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