1. Aldon Corporation
2. Atlantic Equipment Engineers Inc.
3. Calgon Carbon Corporation by Kuraray Co. Ltd
4. Dicalite Management Group
5. Imerys S.A
6. JiLin Yuantong Mineral Co. Ltd.
7. Merck KGaA
8. Noah Chemicals Inc.
9. Qingdao Best Diatomite CO. LTD.
10. Selective Minerals And Color Industries Private Limited.
11. Showa Chemical Industry Co. Ltd.
12. The Diamix Group
13. U.S. Silica Holdings Inc.