Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5196401 | Method of enhancing rock fragmentation and extending drill bit life | William H. Engelmann, Sanaa E. Khalafalla, John E. Pahlman, Patrick A. Tuzinski | 1993-03-23 |
| 4959164 | Rock fragmentation method | William H. Engelmann, Patrick A. Tuzinski, John E. Pahlman, Sanaa E. Khalafalla | 1990-09-25 |