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                                                                    EXHIBIT 99.3




                    INSTRUCTIONS TO REGISTERED HOLDER AND/OR
         BOOK-ENTRY TRANSFER FACILITY PARTICIPANT FROM BENEFICIAL OWNER

                                       OF

                            CENTURY ALUMINUM COMPANY
              11 3/4% SENIOR SECURED FIRST MORTGAGE NOTES DUE 2008

To Registered Holder and/or Participant of the Book-Entry Transfer Facility:

    The undersigned hereby acknowledges receipt of the Prospectus, dated , 2000
(the "Prospectus") of Century Aluminum Company, a Delaware corporation (the
"Company"), and the accompanying Letter of Transmittal (the "Letter of
Transmittal"), that together constitute the Company's offer (the "Exchange
Offer"). Capitalized terms used but not defined herein have the meanings
ascribed to them in the Prospectus.

    This will instruct you, the registered holder and/or book-entry transfer
facility participant, as to action to be taken by you relating to the Exchange
Offer with respect to the 11 3/4% Senior Secured First Mortgage Notes due 2008
(the "Notes") held by you for the account of the undersigned.

    The aggregate face amount of the Notes held by you for the account of the
undersigned is (FILL IN AMOUNT):

$                   of the 11 3/4% Senior Secured First Mortgage Notes due 2008

    With respect to the Exchange Offer, the undersigned hereby instructs you
(CHECK APPROPRIATE BOX):

    [_] TO TENDER the following Notes held by you for the account of the
undersigned (INSERT PRINCIPAL AMOUNT OF NOTES TO BE TENDERED, IF ANY):$

    [_] NOT TO TENDER any Notes held by you for the account of the undersigned.


    If the undersigned instruct you to tender the Notes held by you for the
account of the undersigned, it is understood that you are authorized: (a) to
make, on behalf of the undersigned (and the undersigned, by its signature below,
hereby makes to you), the representation and warranties contained in the Letter
of Transmittal that are to be made with respect to the undersigned as a
beneficial owner, including but not limited to the representations that (i) the
undersigned's principal residence is in the state of (FILL IN
STATE)____________________, (ii) the undersigned is acquiring the Exchange Notes
in the ordinary course of business of the undersigned, (iii) the undersigned is
not participating, does not participate, and has no arrangement or understanding
with any person to participate in the distribution of the Exchange Notes, (iv)
the undersigned acknowledges that any person participating in the Exchange Offer
for the purpose of distributing the Exchange Notes must comply with the
registration and prospectus delivery requirements of the Securities Act of 1933,
as amended (the "Act"), in connection with a secondary resale transaction of the
Exchange Notes acquired by such person and cannot rely on the position of the
Staff of the Securities and Exchange Commission set forth in no- action letters
that are discussed in the section of the Prospectus entitled "The Exchange Offer
-- Resales of the Exchange Notes," and (v) the undersigned is not an
"affiliate," as defined in Rule 405 under the Act, of the Company; (b) to agree,
on behalf of the undersigned, as set forth in the Letter of Transmittal; and (c)
to take such other action as necessary under the Prospectus or the Letter of
Transmittal to effect the valid tender of such Notes.

                            SIGNATURE PAGE TO FOLLOW
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                SIGN HERE

Name of beneficial owner(s):

____________________________


Signature(s):

____________________________


Name (please print):

____________________________

Address:

____________________________

____________________________

____________________________

Telephone number:

____________________________

Taxpayer Identification or Social Security Number:

____________________________

Date:

____________________________