Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4440070 | Mobile adjustable curtain apparatus for use in room and pillar coal mining ventilation system | David Vehovic | 1984-04-03 |
| 4368789 | Drilling apparatus | Thomas M. Orr | 1983-01-18 |
| 4330044 | Drill bit | Thomas M. Orr | 1982-05-18 |