Patent US1661389A successfully refreshed from Google Patents.
US1661389A
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US
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Method of mining oil and the like
Assignee: MIDWEST REFINING Co
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Filing: 1926-10-16
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Granted: 1928-03-06
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Expires: 1946-10-16
Abstract
No abstract record available.
Inventors
- 👤 Ewart G Sinclair
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:07
CPC Classifications
E; E21; E21C; E21C41/00; E21C41/16; E21C41/24
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1931-03-06 | 1931-09-05 | 1932-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1935-03-06 | 1935-09-05 | 1936-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1939-03-06 | 1939-09-05 | 1940-03-06 | $7700.00 | Window Closed / Lapsed |