Issued Patents 1989
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4798417 | Method of separating the upper coal in seams | Gunter Blumenthal, Karl-Heinz Berger, Siegmar Block | 1989-01-17 |
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4798417 | Method of separating the upper coal in seams | Gunter Blumenthal, Karl-Heinz Berger, Siegmar Block | 1989-01-17 |