E21F SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINAGE IN OR OF MINES OR TUNNELS
Introduced: September 1968
Last revised: July 1974
Classification Context
- Section:
- FIXED CONSTRUCTIONS
- Class:
- EARTH OR ROCK DRILLING; MINING
- Subclass:
- SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINAGE IN OR OF MINES OR TUNNELS
Description
E21F covers safety and operational infrastructure systems specific to underground mining and tunneling environments. This subclass encompasses devices and methods for worker protection, personnel rescue, material transport, mine ventilation systems, water drainage, and mine filling operations. The classification addresses the unique hazards of subsurface work, including gas accumulation, flooding, equipment movement, and emergency evacuation requirements. Adjacent classes E21C (drilling and boring) and E21D (mining) focus on extraction methods, whereas E21F emphasizes the support systems and safety infrastructure necessary for safe mining and tunnel operations.
Filing statistics
IPC subclass E21F recorded 72,973 patent applications worldwide between 2013 and 2023. Annual filings grew from 3,134 in 2013 to 11,338 in 2023 (+262%). The most active applicants in class E21 are HALLIBURTON ENERGY SERVICES GROUP (26,607 applications), PETROCHINA COMPANY (14,382 applications) and SINOPEC (CHINA PETROCHEMICAL CORPORATION) (10,137 applications).
Source: EPO PATSTAT, worldwide filings
Related Keywords
10 direct subcodes
Child Classifications
Navigate with arrow keys, Enter to open
- E21F 1/00 Ventilation of mines or tunnels; Distribution of ventilating currents
- E21F 11/00 Rescue devices or other safety devices, e.g. safety chambers or escape ways
- E21F 13/00 Transport specially adapted to underground conditions
- E21F 15/00 Methods or devices for placing filling-up materials in underground workings
- E21F 16/00 Drainage
- E21F 17/00 Methods or devices for use in mines or tunnels, not covered elsewhere
- E21F 3/00 Cooling or drying of air
- E21F 5/00 Means or methods for preventing, binding, depositing or removing dust; Preventing explosions or fires
- E21F 7/00 Methods or devices for drawing-off gases with or without subsequent use of the gas for any purpose
- E21F 9/00 Devices preventing sparking of machines or apparatus
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