Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5967616 | Electrical control system for apparatus and method for continuous underground mining | David A. Christopher | 1999-10-19 |
| 5810447 | Apparatus and method for continuous mining | David A. Christopher | 1998-09-22 |
| 5709433 | Apparatus for continuous mining | David A. Christopher | 1998-01-20 |
| 5667279 | Apparatus and method for continuous mining | David A. Christopher | 1997-09-16 |