1. Calcinor SA
2. Carmeuse Group
3. Great Lakes Calcium Corporation
4. Imerys S.A.
5. J.M. Huber Corporation
6. Kerford Limestone Co
7. Lhoist Group
8. Magnesita Refractories Co
9. Minerals Technologies Inc.
10. Mississippi Lime Company
11. Omya AG
12. Provencale SA
13. Sibelco Group
14. The National Lime & Stone Company