Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4883322 | Mining and conveying apparatus | Heinz Kunzer, Kurt Plaga | 1989-11-28 |
| 4798417 | Method of separating the upper coal in seams | Gustav Neu, Karl-Heinz Berger, Siegmar Block | 1989-01-17 |