Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5199515 | Dry pneumatic system for hard rock shaft drilling | John R. England | 1993-04-06 |
| 5125692 | Dry pneumatic system for hard rock shaft drilling | John R. England | 1992-06-30 |
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5199515 | Dry pneumatic system for hard rock shaft drilling | John R. England | 1993-04-06 |
| 5125692 | Dry pneumatic system for hard rock shaft drilling | John R. England | 1992-06-30 |