E21D 17/08
Cap joints for obtaining a coal-face free of pit-props
E21D17/08 (Cap joints for obtaining a coal-face free of pit-props) appears on 1 US grants and 0 published applications in this corpus.
Search patents in E21D- Granted patents
- 1
- Published applications
- 0
- Assignees
- 1
- Inventors
- 1
- Latest grant
- 16 Nov 1976
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| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
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