Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4820081 | Head seal for a mine stopping | John M. Kennedy | 1989-04-11 |
| RE32871 | Mine stopping | John M. Kennedy | 1989-02-21 |
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4820081 | Head seal for a mine stopping | John M. Kennedy | 1989-04-11 |
| RE32871 | Mine stopping | John M. Kennedy | 1989-02-21 |