| Relationships | Role | Relationship Start | Relationship End |
| Rossma Beteiligungsgesellschaft Mbh | Parent | 12/31/1980 | 8/27/1989 |
| Didier Taylor Refractories Corp. | Subsidary | 12/31/1980 | 8/27/1989 |
| Zircoa Inc. | Subsidary | 12/9/1987 | 8/27/1989 |
| North American Refractories Company (Narco) | Subsidary | 4/27/1988 | 8/27/1989 |