Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5669739 | Prestressing of mine props | — | 1997-09-23 |
| 5547317 | Mine support system | Mark Howell | 1996-08-20 |
| 5318387 | Yieldable load support | Frans R. P. Pienaar, Brian Peter Lewis, Mark Howell, Richard G. King, Peter J. Cook | 1994-06-07 |