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PCE
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CPC Subgroup
E21C 41/28

for brown or hard coal

Full Title

Methods of underground or surface mining (E21C45/00 takes precedence); Layouts therefor (for peat E21C49/00) > Methods of surface mining (machines for obtaining, or the removal of, materials in open-pit mines E21C47/00); Layouts therefor > for brown or hard coal

Top Applicants

Top 10 applicants by patent filingsfor class E21, 2013–2023, worldwide · Source: EPO PATSTAT

  1. HALLIBURTON ENERGY SERVICES GROUP US 27,652
  2. SAUDI ARABIAN OIL COMPANY SA 7,755
  3. PETROCHINA COMPANY 7,025
  4. BAKER HUGHES US 6,589
  5. SCHLUMBERGER TECHNOLOGY US 6,151
  6. SINOPEC (CHINA PETROCHEMICAL CORPORATION) 4,443
  7. SCHLUMBERGER TECHNOLOGY NL 4,255
  8. CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 3,991
  9. SERVICES PETROLIERS SCHLUMBERGER FR 3,300
  10. SCHLUMBERGER CANADA CA 3,086