EXHIBIT 21


                                  SUBSIDIARIES


1.       American Shield Coal Company is a Texas corporation doing business
         under its corporate name.

2.       Pioche-Ely Valley Mines, Inc. is a Nevada corporation doing business
         under its corporate name. The Company beneficially owns approximately
         51% of the capital stock of Pioche-Ely Valley.

3.       American Shield Refining Company is a Texas corporation doing business
         under its corporate name.

4.       Texas Oil and Chemical Co. II, Inc. is a Texas corporation doing
         business under its corporate name. American Shield Refining Company
         owns 100% of the capital stock of Texas Oil and Chemical.

5.       South Hampton Refining Co. is a Texas corporation doing business under
         its corporate name. Texas Oil and Chemical Co. II, Inc. owns 100% of
         the capital stock of South Hampton.

6.       INC Acquisition Company is a Delaware corporation doing business as INC
         Surveys. American Shield Refining Company owns 15% of the capital stock
         of INC Acquisition Company.

7.       Productos Quimicos Coin, S.A. de C.V. is a Mexico corporation doing
         business under its corporate name. Texas Oil and Chemical Co. II, Inc.
         owns approximately 92% of the capital stock of Productos Quimicos Coin,
         S.A.