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                                                                    EXHIBIT 3.12

                                     BY-LAWS

                                       OF

                            PORTER BROS. CORPORATION

                                    ARTICLE I
                                     OFFICES

         Section 1. The registered office shall be located in Bismarck, North
Dakota.

         Section 2. The corporation may also have offices at such other places
both within and without the State of North Dakota as the board of directors may
from time to time determine or the business of the corporation may require.

                                   ARTICLE II
                            MEETINGS OF SHAREHOLDERS

         Section 1. All meetings of shareholders for the election of directors
shall be held at such place as may be fixed from time to time by the board of
directors.

         Section 2. Regular meetings of shareholders need not be held unless
demanded by a shareholder pursuant to Section 10-19.1-17 (2) of the North Dakota
Business Corporation Act. At any regular meeting, the shareholders shall elect
by plurality vote a board of directors, and transact such other business as may
properly be brought before the meeting.

         Section 3. Written or printed notice of the regular meeting stating the
place, day and hour of the meeting shall be delivered not less than ten nor more
than fifty days before the date of the meeting, either personally or by mail, by
or at the direction of the president, the secretary, or the officer or persons
calling the meeting, to each shareholder or record entitled to vote at such
meeting.

         Section 4. The business transacted at any special meeting of
shareholders shall be limited to the purposes stated in the notice.

                                   ARTICLE III
                           QUORUM AND VOTING OF SHARES

         Section 1. The holders of a majority of the shares issued and
outstanding and entitled to vote, represented in person or by proxy, shall
constitute a quorum at all meetings of the shareholders for the transaction of
business except as otherwise provided by statute. If, however, such quorum shall
not be present or represented at any meeting of the shareholders, the
shareholders present in person or represented by proxy shall have power to
adjourn the meeting from time to time, without notice other than announcement at
the meeting, until a quorum shall be present or represented. At such adjourned
meeting at which a quorum shall be present or represented any business may be
transacted which might have been transacted at the meeting as originally
notified.


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         Section 2. If a quorum is present, the affirmative vote of a majority
of the shares represented at the meeting shall be the act of the shareholders
unless the vote of a greater number of shares is required by law or the articles
of incorporation.

         Section 3. Each outstanding share, having voting power shall be
entitled to one vote on each matter submitted to a vote at a meeting of
shareholders. A shareholder may vote either in person or by proxy executed in
writing by the shareholder or by his duly authorized attorney-in-fact.

         If notice in writing is given by any shareholder to any officer before
the time fixed for holding a meeting for the election of directors that he
intends to cumulate his votes in such election, each shareholder shall have the
right to multiply the number of votes to which he may be entitled by the number
of directors to be elected and he may cast all such votes for one candidate, or
distribute them among any two or more candidates.

         Section 4. Any action required or permitted to be taken at a meeting of
the shareholders may be taken without a meeting by written action signed by all
of the shareholders entitled to vote on that action. The written action is
effective when it has been signed by all of those shareholders, unless a
different effective time is provided in the written action.

                                   ARTICLE IV
                                    DIRECTORS

         Section 1. The number of directors shall be two. Directors need not be
residents of the State of North Dakota nor shareholders of the corporation. The
directors, other than the first board of directors, shall be elected at a
regular meeting (or by written action) of the shareholders, and each director
elected shall serve for an indefinite term that expires at the next regular
meeting of shareholders and shall hold office until a successor is elected and
has qualified, or until the earlier death, resignation, removal or
disqualification of the director.

         Section 2. Vacancies on the board resulting from the death,
resignation, removal or disqualification of a director may be filled by the
affirmative vote of the majority of the remaining directors, although the
remaining directors constitute less than a quorum; and vacancies on the board
resulting from duly created directorships may be filled by the affirmative vote
of the directors serving at the time of the increase. Each director elected to
fill a vacancy shall hold office until a qualified successor is elected by the
shareholders at the next regular or special meeting of the shareholders, or
until the earlier death, resignation or removal or disqualification of the
director.

         Section 3. The business affairs of the corporation shall be managed by
its board of directors which may exercise all such powers of the corporation and
do all such lawful acts and things as are not by statute or by the articles of
incorporation or by these by-laws directed or required to be exercised or done
by the shareholders.

         Section 4. The directors may keep the books of the corporation, except
such as are required by law to be kept within the state, outside of the State of
North Dakota, at such place or places as they may from time to time determine.


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         Section 5. The board of directors, by the affirmative vote of a
majority of the directors then in office, and irrespective of any personal
interest of any of its members, shall have authority to establish reasonable
compensation of all directors for services to the corporation as directors,
officers or otherwise.

                                    ARTICLE V
                       MEETINGS OF THE BOARD OF DIRECTORS

         Section 1. Meetings of the board of directors, regular or special, may
be held either within or without the State of North Dakota.

         Section 2. The first meeting of each newly elected board of directors
shall be held at such time and place as shall be fixed by the vote of the
shareholders at the regular meeting at which directors are elected, and no
notice of such meeting shall be necessary to the newly elected directors in
order legally to constitute the meeting, provided a quorum shall be present; or
it may convene at such place and time as shall be fixed by the consent in
writing of all the directors.

         Section 3. Regular meetings of the board of directors may be held upon
such notice, or without notice, and at such time and at such place as shall from
time to time be determined by the board of directors.

         Section 4. Special meetings of the board of directors may be called by
the president on three days' notice to each director, either personally or by
mail or by facsimile; special meetings shall be called by the president or
secretary in like manner and on like notice upon written request of any
director.

         Section 5. Attendance of a director at any meeting shall constitute a
waiver of notice of such meeting, except where a director attends for the
express purpose of objecting to the transaction of any business because the
meeting is not lawfully called or convened. Neither the business to be
transacted at, nor the purpose of, any regular or special meeting of the board
of directors need be specified in the notice or waiver of notice of such
meeting.

         Section 6. A majority of the directors currently holding office shall
constitute a quorum for the transaction of business unless a greater number is
required by statute. The act of a majority of the directors present at any
meeting at which a quorum is present shall be the act of the board of directors,
unless the act of a greater number is required by statute. If a quorum shall not
be present at any meeting of directors, the directors present thereat may
adjourn the meeting from time to time, without notice other than announcement at
the meeting, until a quorum shall be present.

                                   ARTICLE VI
                                   COMMITTEES

         Section 1. The board of directors by resolution adopted by the
affirmative majority vote of the board may designate one individuals, who need
not be directors, to constitute a committee, which committee shall have or more
and exercise only to the extent provided in such resolution the authority of the
board of directors in the management of the corporation, except as otherwise

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required by law. Vacancies in the membership of the committee shall be filled by
the board of directors at a regular or special meeting of the board of
directors. The committee shall keep regular minutes of its proceedings which
shall be made available on request to members of the committee and shall be
promptly distributed to each director.

                                   ARTICLE VII
                                     NOTICES

         Section 1. Whenever, under the provisions of the statutes or of the
articles of incorporation or of these by-laws, notice is required to be given
any director or shareholder, it shall not be construed to mean personal notice,
but such notice may be given in writing, by mail, addressed to such director or
shareholder, at his address as it appears on the records of the corporation,
with postage thereon prepaid, and such notice shall be deemed to be given at the
time when the same shall be deposited in the United States or Canadian mail.
Notice to directors may also be given by telegram (or by facsimile, if the
director has provided a facsimile number for this purpose).

         Section 2. Whenever any notice is required to be given under the
provisions of the statues or under the provisions of the articles of
incorporation or these bylaws, a waiver thereof in writing signed by the person
or person entitled to such notice, whether before or after the time stated
therein, shall be deemed equivalent to the giving of such notice.

                                  ARTICLE VIII
                                    OFFICERS

         Section 1. The officers of the corporation shall be chosen by the board
of directors and shall be a president, a vice-president, a secretary and a
treasurer. The board of directors may also choose additional vice-presidents,
and one or more assistant secretary and assistant treasurer.

         Section 2. The board of directors shall choose the officers described
in Section 1, none of whom needs to be a member of the board or a shareholder,
at its first meeting after each regular meeting of shareholders.

         Section 3. The board of directors may appoint such other officers and
agents as it shall deem necessary who shall hold their offices for such terms
and shall exercise such powers and perform such duties as shall be determined
from time to time by the board of directors.

         Section 4. The salaries of all officers and agents of the corporation
shall be fixed by the board of directors.

         Section 5. The officers of the corporation shall hold office until
their successors are chosen and qualify; but an officer may be removed at any
time, with or without cause, by the affirmative vote of a majority of the
directors present, without prejudice to any contractual rights or obligations.
Any vacancy occurring in any office of the corporation may be filled by the
board of directors.


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                                  THE PRESIDENT

         Section 6. The president shall be the chief executive officer of the
corporation, shall preside at all meetings of the shareholders and the board of
directors, shall have general and active management of the business of the
corporation and shall see that all orders and resolutions of the board of
directors are carried into effect.

         Section 7. He shall execute bonds, mortgages and other contracts of the
corporation, except where required or permitted by law to be otherwise signed
and executed and except where the signing and execution thereof shall be
expressly delegated by the board of directors to some other officer or agent of
the corporation.

                               THE VICE-PRESIDENTS

         Section 8. The vice-president, or if there shall be more than one, the
vice-presidents in the order determined by the board of directors, shall, in the
absence or disability of the president, perform the duties and exercise the
powers of the president and shall perform such other duties and have such other
powers as the board of directors may from time to time prescribe.

                     THE SECRETARY AND ASSISTANT SECRETARIES

         Section 9. The secretary shall attend all meetings of the board of
directors and all meetings of the shareholders and record all the proceedings of
the meetings of the corporation and of the board of directors in a book to be
kept for that purpose and shall perform like duties for committees of the board
when required. He shall give, or cause to be given, notice of all meetings of
the shareholders and special meeting of the board of directors, and shall
perform such other duties as may be prescribed by the board of directors or
president, under whose supervision he shall be.

         Section 10. The assistant secretary, or if there be more than one, the
assistant secretaries in the order determined by the board of directors, shall,
in the absence or disability of the secretary, perform the duties and exercise
the powers of the secretary and perform such other duties and have such other
powers as the board of directors may from time to time prescribe.

                     THE TREASURER AND ASSISTANT TREASURERS

         Section 11. The treasurer shall have the custody of the corporate funds
and securities and shall keep full and accurate accounts of receipts and
disbursements in books belonging to the corporation and shall deposit all moneys
and other valuable effects in the name and to the credit of the corporation in
such depositories as may be designated by the board of directors.

         Section 12. He shall disburse the funds of the corporation as may be
ordered by the board of directors, taking proper vouchers for such
disbursements, and shall render to the president and the board of directors, at
its regular meetings, or when the board of directors so requires, an account of
all his transactions as treasurer and of the financial condition of the
corporation.


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         Section 13. If required by the board of directors, he shall give the
corporation a bond in such sum and with such surety or sureties as shall be
satisfactory to the board of directors for the faithful performance of the
duties of his office and for the restoration to the corporation, in case of his
death, resignation, retirement or removal from office, of all books, papers,
vouchers, money and other property of whatever kind in his possession or under
his control belonging to the corporation.

         Section 14. The assistant treasurer, or, if there shall be more than
one, the assistant treasurers in the order determined by the board of directors,
shall, in the absence or disability of the treasurer, perform the duties and
exercise of the powers of the treasurer and shall perform such other duties and
have such other powers as the board of directors may from time to time
prescribe.

                                   ARTICLE IX
                             CERTIFICATES FOR SHARES

         Section 1. The shares of the corporation shall be represented by
certificates signed by the president or a vice-president and the secretary or an
assistant secretary of the corporation.

         Section 2. The signatures of the officers of the corporation upon a
certificate may be facsimiles if the certificate is countersigned by a transfer
agent, or registered by a registrar, other than the corporation itself or an
employee of the corporation. In case any officer who has signed or whose
facsimile signature has been placed upon such certificate shall have ceased to
be such officer before such certificate is issued, it may be issued by the
corporation with the same effect as if he were such officer at the date of its
issue.

                                LOST CERTIFICATES

         Section 3. The board of directors may direct a new certificate to be
issued in place of any certificate theretofore issued by the corporation alleged
to have been lost, stolen or destroyed. When authorizing such issue of a new
certificate, the board of directors, in its discretion and as a condition
precedent to the issuance thereof, may prescribe such terms and conditions as it
deems expedient, and may require such indemnities as it deems adequate, to
protect the corporation from any claim that may be made against it with respect
to any such certificate alleged to have been lost or destroyed.

                               TRANSFER OF SHARES

         Section 4. Upon surrender to the corporation of the transfer agent of
the corporation of a certificate representing shares duly endorsed or
accompanied by proper evidence of succession, assignment or authority to
transfer, a new certificate shall be issued to the person entitled thereto, and
the old certificate canceled and the transaction recorded upon the books of the
corporation.

                            CLOSING OF TRANSFER BOOKS

         Section 5. For the purpose of determining shareholders entitled to
notice of or to vote at any meeting of shareholders, or any adjournment thereof
or entitled to receive payment of any dividend, or in order to make a
determination of shareholders for any other proper purpose, the

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board of directors may provide that the stock transfer books shall be closed for
a stated period but not to exceed, in any case, fifty days. If the stock
transfer books shall be closed for the purpose of determining shareholders
entitled to notice of or to vote at a meeting of shareholders, such books shall
be closed for at least ten days immediately preceding such meeting. In lieu of
closing the stock transfer books, the board of directors may fix in advance a
date as the record date for any such determination of shareholders, such date in
any case to be not more than fifty days and, in case of a meeting of
shareholders, not less than ten days prior to the date on which the particular
action, requiring such determination of shareholders, is to be taken. If the
stock transfer books are not closed and no record date is fixed for the
determination of shareholders entitled to notice of or to vote at a meeting of
shareholders, or shareholders entitled to receive payment of a dividend is
adopted, as the case may be, shall be the record date for such determination of
shareholders. When a determination of shareholders entitled to vote at any
meeting of shareholders has been made as provided in this section, such
determination shall apply to any adjournment thereof.

                             REGISTERED SHAREHOLDERS

         Section 6. The corporation shall be entitled to recognize the exclusive
right of a person registered on its books as the owner of shares to receive
dividends, and to vote as such owner, and shall not be bound to recognize any
equitable or other claim to or interest in such share or shares on the part of
any other person, whether or not the corporation shall have express or other
notice thereof, except as otherwise provided by the laws of North Dakota.

                              LIST OF SHAREHOLDERS

         Section 7. The officer or agent having charge of the transfer books for
shares shall make, at least ten days before each meeting of shareholders, a
complete list of the shareholders entitled to vote at such meeting, arranged in
alphabetical order, with the address of each and the number of shares held by
each, which list, for a period of ten days prior to such meeting, shall be kept
on file at the registered office of the corporation and shall be subject to
inspection by any shareholder at any time during usual business hours. Such list
shall also be produced and kept open at the time and place of the meeting and
shall be subject to the inspection of any shareholder during the whole time of
the meeting. The original share ledger or transfer book, or a duplicate thereof
shall be prima facie evidence as to who are the shareholders entitled to examine
such list or share ledger or transfer book or to vote at any meeting of the
shareholders.

                                    ARTICLE X
                               GENERAL PROVISIONS

                        DIVIDENDS AND OTHER DISTRIBUTIONS

         Section 1. Dividends or other distributions may be declared by the
board of directors at any regular or special meeting in compliance with the
requirements of the North Dakota Business Corporation Act. Distributions may be
paid in cash, in property or in common shares.

                                     CHECKS


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         Section 2. All checks or demands for money and notes of the corporation
shall be signed by such officer or officers or such other person or persons as
the board of directors may from time to time designate.

                                   FISCAL YEAR

         Section 3. The fiscal year of the corporation shall be fixed by
resolution of the board of directors.

                                   ARTICLE XI
                                   AMENDMENTS

         Section 1. These by-laws may be altered, amended, or repealed or new
by-laws may be adopted by the affirmative vote of a majority of the board of
directors at any regular or special meeting of the board; provided that after
the adoption of the initial bylaws, the board may not adopt, amend or repeal a
by-law fixing a quorum for meetings of shareholders, prescribing procedures for
removing directors or filling vacancies on the board, or fixing the number of
directors or their classifications, qualifications, or terms of office, but may
adopt or amend a by-law to increase the number of directors.

         Section 2. These by-laws may be altered, amended or repealed or new
by-laws may be adopted at any regular or special meeting of shareholders at
which a quorum is present or represented, by the affirmative vote of a majority
of the shares entitled to vote, in accordance with the procedures set forth in
the North Dakota Business Corporation Act.


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                                  BY-LAW NO. 2

                                       OF

                            PORTER BROS. CORPORATION

         being a by-law increasing the number of directors of the Corporation

         BE IT ENACTED as a by-law of Porter Bros. Corporation (hereinafter
called the "Corporation") as follows:

1. The number of directors of the Corporation be and the same is hereby
increased from two to three so that the Board of Directors of the Corporation
shall hereafter be composed of three directors.

2. All prior by-laws and resolutions of the Corporation inconsistent herewith be
and the same are hereby amended, modified and revised in order to give effect to
this by-law.

         MADE by the Board as of June 30, 1996.

                                                    Glen Beeby
                                                    ----------------------------
Glen Beeby

                                                    Paul Kelly
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Paul Kelly


         CONFIRMED by the sole shareholder as of June 30, 1996.

                                          GERDAU MRM STEEL INC.

                                     By:  Glen Beeby
                                          --------------------------------------
                                          Glen Beeby
                                          Secretary and Treasurer