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                                                             EXHIBIT 10.3(b)

                        MAGNESIUM CORPORATION OF AMERICA
                               238 NORTH 2200 WEST
                           SALT LAKE CITY, UTAH 84116


                                  June 11, 1996


Mr. Ron L. Thayer
c/o Magnesium Corporation of America
238 North 2200 West
Salt Lake City, Utah  84116


Dear Sir: 

                  Reference is made to your net worth appreciation participation
agreement with this Corporation (the "Agreement").

                  This will confirm our agreement with you as follows:

                  1. As you know, our parent company, Renco Metals, Inc. ("Renco
         Metals") is contemplating a refinancing under which it will issue
         $150,000,000 of Senior Notes due 2003 ("New Notes") and retire its
         presently outstanding $75,000,000 of Senior Notes due 2000 (the
         "Existing Notes"). On the issuance of the New Notes this company will
         pay a dividend to Renco Metals. Concurrently with the payment of such
         dividend this company will make a payment to you on account of the
         dividend and the Agreement and you will accept same in full settlement
         of all of your rights arising from the payment of the dividend. In
         consideration of such payment and your agreement to the amendments to
         the Agreement as outlined in paragraph 2 below, the Company agrees that
         although after paying the above mentioned payment "Cumulative Net
         Income" under the Agreement would be approximately negative
         $50,000,000, nevertheless, your Cumulative Net Income will be deemed to
         be zero as of July 31, 1996. Your Cumulative Net Income participation
         shall be calculated on the company's Cumulative Net Income accruing
         after that date.

                  2. Notwithstanding anything in the Agreement in the contrary,
         you agree, effective upon your receipt of the payment referred to in
         paragraph 1 of this letter, as follows:

                           (a) Should you voluntarily leave the employ of this
                  company before the earlier of the 15th anniversary of this
                  agreement or your attainment of age 62, then the payment of
                  the Payment (as defined in the "Agreement") to you shall not
                  commence until such anniversary or your attaining age 62.
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                           Notwithstanding the foregoing, payments shall
                  commence immediately upon your death or upon your continuing
                  disability making it impossible for you to continue to perform
                  your normal business duties.


                           (b) You agree that, so long as you are entitled to
                  any part of the Payment, you will not, directly or indirectly,
                  whether as employee, consultant, proprietor, partner,
                  stockholder or other capacity, engage in any aspect of the
                  magnesium business (production, marketing, sales, use) in any
                  part of the world. In this respect, you and we acknowledge
                  that the primary magnesium industry is a worldwide industry,
                  that the participants therein compete against each other in
                  all parts of the world, and that therefore this restriction is
                  reasonable.

                               Should you engage in any activity proscribed by
                  the preceding paragraph then the company's obligation to you
                  to make the Payment (or any unpaid part thereof) shall
                  automatically and permanently cease, and you shall be deemed
                  to have irrevocably released you right to same.

                           (c) Should you voluntarily leave the company, you
                  shall give 30 days advance written notice, and the amount of
                  your Payment will be calculated as to the close of the fiscal
                  quarter in which such 30 day notice period ends. 

                  3. The parties hereby reaffirm the Agreement as amended
                  hereby.

                  Please confirm your agreement to the foregoing by signing and
returning the enclosed copy.

                                            Very truly yours, 

                                            MAGNESIUM CORPORATION 
                                              OF AMERICA

                                            By /s/ Michael H. Legge
                                            -----------------------

CONFIRMED AND AGREED TO:


   /s/ Ron L. Thayer
-------------------------
     Ron L. Thayer