EXHIBIT 21 SUBSIDIARIES OF REGISTRANT Registrant has no parent; see proxy statement for Registrant's principal shareholders. The following are Registrant's subsidiaries which are included in the consolidated financial statements: Name of Subsidiary State or Other (Each Owned 100% by Registrant Jurisdiction Except as Otherwise Stated) of Incorporation --------------------------------------- ------------------- Castle Concrete Company Colorado Continental Catalina, Inc.* Arizona Continental Copper, Inc. Arizona Continental Quicksilver, Inc. Idaho Continental Uranium, Inc. Colorado Edens Industrial Park, Inc. Illinois Phoenix Manufacturing, Inc. Arizona ProSoft International, Inc.** Colorado Rocky Mountain Ready Mix Concrete, Inc.*** Colorado Transit Mix Concrete Co. Colorado Transit Mix of Pueblo, Inc. Colorado Williams Furnace Co. Delaware * owned by Continental Copper, Inc. **owned by Transit Mix Concrete Co. ***acquired December 31 2000