E21C 41/18
For brown or hard coal
Official title: for brown or hard coal
E21C41/18 (For brown or hard coal) appears on 133 US grants and 112 published applications in this corpus.
Search patents in E21C- Granted patents
- 133
- Published applications
- 112
- Assignees
- 72
- Inventors
- 585
- Latest grant
- 30 Jun 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 2 | 0 |
| 1977 | 7 | 0 |
| 1978 | 5 | 0 |
| 1979 | 1 | 0 |
| 1980 | 7 | 0 |
| 1981 | 5 | 0 |
| 1982 | 3 | 0 |
| 1983 | 4 | 0 |
| 1984 | 1 | 0 |
| 1985 | 1 | 0 |
| 1986 | 1 | 0 |
| 1987 | 1 | 0 |
| 1988 | 0 | 0 |
| 1989 | 2 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 1 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 1 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 0 | 0 |
| 2004 | 0 | 0 |
| 2005 | 0 | 0 |
| 2006 | 0 | 0 |
| 2007 | 0 | 0 |
| 2008 | 0 | 0 |
| 2009 | 0 | 0 |
| 2010 | 0 | 2 |
| 2011 | 1 | 2 |
| 2012 | 2 | 1 |
| 2013 | 2 | 4 |
| 2014 | 3 | 6 |
| 2015 | 4 | 4 |
| 2016 | 4 | 4 |
| 2017 | 4 | 3 |
| 2018 | 2 | 6 |
| 2019 | 3 | 5 |
| 2020 | 8 | 17 |
| 2021 | 10 | 12 |
| 2022 | 6 | 8 |
| 2023 | 8 | 15 |
| 2024 | 18 | 7 |
| 2025 | 11 | 8 |
| 2026 | 5 | 8 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Permeability enhancement device for coal-seam gas drainage30 Jun 2026US 12,669,055 B2Henan Polytechnic University
- High-concentration filling slurry of coal gangue and preparation method thereof9 Jun 2026US 12,649,887 B1Taiyuan University of Science and Technology
- Static crushing directional anchor withdrawal method at end of large-mining-height working face21 Apr 2026US 12,607,121 B2Huating Coal Group Co., Ltd.
- Method for recovering residual coal pillars by Freezing water accumulated in room-and-pillar mining area10 Mar 2026US 12,571,308 B2Taiyuan University of Technology
- Tunnel tunneling system3 Mar 2026US 12,565,837 B2Ccteg Taiyuan Research Institute
- Underground mining system and method30 Jul 2026US 2026/0218612 A1
- Post-mining water-resisting layer reconstruction method and related device23 Jul 2026US 2026/0210248 A1China University of Mining and Technology, Beijing
- Methods, devices, and storage medium for synchronous treatment of water hazard and subsidence25 Jun 2026US 2026/0176970 A1China University of Mining and Technology, Beijing
- High-concentration filling slurry of coal gangue and preparation method thereof11 Jun 2026US 2026/0159773 A1Taiyuan University of Science and Technology
- Method for determining feasibility of water-preserving mining with in-situ protection of floor confined water4 Jun 2026US 2026/0153426 A1China University of Mining and Technology
Most cited
By later US patents
- Slagging coal combustor for cementitious slag production, metal oxide reduction, shale gas and oil recovery, enviromental remediation, emission control and CO2 sequestration77US 8,337,613 B22012
- Hydraulic mining method56US 4,536,035 AThe United States of America as represented by the United States Department of Energy · 1985
- Underground mineral extraction48US 4,226,475 A1980
- Variable length conveyor assembly29US 4,474,287 A1984
- Continuous mining apparatus and method25US 4,312,540 A1982