Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4889694 | Recovery of zinc values from zinc and iron-bearing sulfide materials | Donald R. Spink | 1989-12-26 |
| 4865817 | Gas reacting apparatus | J. Stuart Burgess, Donald R. Spink | 1989-09-12 |