Exhibit 3.10


                      BY-LAWS OF MICHIGAN ASH SALES COMPANY

Adopted at a meeting of stockholders held on the 3rd day of August, 1967.

                                     OFFICES

      1. The principal office of the corporation shall be in the City of Bay
City, Bay County, Michigan, and the business office of the corporation shall be
in the City of Bay City, Bay County, Michigan. The corporation may also have
offices at such other places as the board of directors may from time to time
appoint or the business of the corporation may require.

                             MEETING OF STOCKHOLDERS

      2. The annual meeting of the stockholders of the corporation for the
election of directors and the transaction of such other business as may properly
come before the meeting shall be held at the principal business office of the
corporation in the State of Michigan, on the 3rd Monday in May, at the hour of
2:00 P.M., in each year, commencing in 1968, if not a legal holiday, and if a
legal holiday, then on the next regular day following at 2:00 P.M. in the
afternoon. Notice of the annual meeting of the stockholders shall be given by
mailing at least ten (10) days previous to such meeting, postage prepaid, a
notice thereof addressed to each common stockholder at such address as shall
appear on the books of the corporation.

      3. The holders of a majority of the voting stock issued and outstanding
present in person or represented by proxy is requisite and shall constitute a
quorum at all meetings of the stockholders for he transaction of business except
as otherwise provided by law or by the articles of incorporation or by these
by-laws. If such majority shall not be present or represented, those present in
person or by proxy shall have power to adjourn the meeting from time to time,
without notice other than announcement at the meeting, until the requisite
amount of stock shall be present, when any business may be transacted which
might have been transacted at the meeting as originally notified.

      4. Special meetings of the stockholders for any purpose or purposes other
than those regulated by statute, may be called by resolution of the board of
directors or by the president, and shall be called by the president and
secretary at the request in writing of a majority of the board of directors, or
at the request in writing by stockholders owning fifty (50) per cent of the
voting stock of the company issued and outstanding. In case of refusal of the
president or secretary to call a meeting when so requested, stockholders of
record owning twenty-five (25) per cent or more of outstanding voting shares may
call a meeting in the manner prescribed herein. Business transacted at all
special meetings shall be confined to the objects stated in the call and matters
germane thereto. Written notice of a special meeting of stockholders stating the
time, place and object thereof shall be mailed, postage prepaid, at least three
days before the meeting to each common stockholder at such address as shall
appear on the books of the company.


                                    DIRECTORS

      5. In accordance with the articles of incorporation, the affairs of the
corporation shall be managed by a board of not less than three nor more than
five directors. Directors need not be stockholders and they shall be elected at
the annual meeting of the corporation, to serve for one year and until
successors are elected and qualified. Any director may be removed from office by
vote of a majority of outstanding voting shares at a meeting of stockholders
duly called for such purpose. A vacancy caused by such removal shall be filled
in like manner. The board of directors may designate an operating, financial, or
other committee from among the members of such board, upon proper resolution
defining and limiting the authority of such committee or committees, and action
duly taken by a majority of such committee or committees shall be deemed
corporate action and binding upon the corporation, if within the scope of the
resolution appointing such committee.

                            COMPENSATION OF DIRECTORS

      6. Directors as such shall not receive any stated salary for their
service; by resolution of the board a fixed sum and expenses of attendance, if
any, may be allowed for attendance at any meeting. Nothing herein contained
shall be construed to preclude any director from serving the corporation in any
other capacity and receiving compensation therefor.

                              MEETINGS OF THE BOARD

      7. Regular meetings of the board shall be held annually on the 3rd Monday
in May, at the hour of 3:00 P.M. in the afternoon, in each year, commencing in
1968, at the office of the company and/or at such other time as the board of
directors may by resolution appoint. Special meetings of the board may be called
by the president on three days' notice to each director, either personally or by
mail or by wire; special meetings shall be called by the president or secretary
on the written request of two directors. In case of refusal of the president or
secretary to call a meeting upon request of directors, call for such meeting may
be signed by two or more directors and notice given in the manner provided for
herein. At all meetings of the board the presence of a majority shall be
necessary to constitute a quorum and sufficient for the transaction of business
and any act of a majority present at a meeting, at which there is a quorum,
shall be the act of the board of directors, except as may be otherwise
specifically provided by statute, or by the Articles of Association or those
by-laws.

                                    OFFICERS

      8. The officers of the corporation shall be a president, vice-president,
secretary, and treasurer, who shall hold office for one year and until their
successors are chosen and qualified in the stand. Any officer elected or
appointed by the board of directors may be removed at any time by the
affirmative vote of a majority of the whole board of directors. Any two of the
above


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offices, except those of president and vice-president, may be held by the same
person, but no officer shall execute, acknowledge, or verify any instrument in
more than one capacity. The board of directors may fix the salaries of the
officers of the corporation.

      9. The board of directors, immediately after each annual meeting of
stockholders, shall appoint from their own number a president, vice-president,
and secretary, and shall also choose a treasurer who need not be a member of the
board; and a majority of the whole number of directors shall be necessary for
appointment of each of said officers.

                                    PRESIDENT

      10. The president shall preside at meetings of the stockholders and
directors and shall see that all orders and resolutions of the board of
directors are carried into effect, subject, however, to the rights of the
directors to delegate any specific powers except as may be by law conferred upon
the president, to any other officer of the corporation.

                                 VICE-PRESIDENT

      11. The vice-president, in the absence of the president, shall perform the
duties and exercise the powers of the president.

                                    SECRETARY

      12. The secretary shall attend all sessions of the board and all meetings
of the stockholders and act as clerk thereof, and record all votes and the
minutes of all proceedings in a book to be kept for that purpose, and shall
perform like duties for any committee of the board when required. He shall cause
to be given notice of all meetings of the stockholders and directors and shall
perform such duties as pertaining to his office. He shall keep in safe custody
the said records of the corporation,; he shall countersign all deeds, leases,
and conveyance executed by the corporation, affix the seal of the corporation
thereto and to such other papers all shall be required or directed to be sealed
and to safely and systematically keep all books, papers, records and documents
belonging to the corporation or in any way pertaining to the business thereof.

                                    TREASURER

      13. The treasurer shall have the custody of all the corporate funds and
securities and shall keep full and accurate accounts of receipts and
disbursements and books belonging to the corporation and shall deposit all
monies and other valuable effects in the name and to the credit of the
corporation in such depositories as he may see fit. The board may secure the
fidelity of any officer by bond or otherwise.



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                                    VACANCIES

      14. Except as otherwise provided by law or these by-laws if the office of
any director or president, vice-president, secretary, treasurer, or other
officer or agent is or remains unfilled or becomes vacant for any reason, the
directors in office, although less than a majority than the whole board, by a
majority vote may choose a director or successor officer who shall hold office
the unexpired term.

                                LOST CERTIFICATE

      15. Any person claiming a certificate of stock to be lost or destroyed
shall make an affidavit or affirmation of that fact and advertise the same in
such manner as the board may required and shall give the corporation a bond of
indemnity in form and with one or more sureties satisfactory to the board, in at
least double the par value of the stock represented by said certificate,
whereupon a new certificate may be issued of the same tenor and for the same
number of shares as the one alleged to be lost or destroyed but always subject
to the approval of the board of directors.

                                TRANSFER OF STOCK

      16. Transfer of stock shall be made on the books of the corporation by the
person named in the certificate or by his attorney or by his attorneys, lawfully
constituted, and upon surrender of such certificate. Every transfer of stock
shall be entered on the stock book of the corporation which shall be kept at its
principal office of business in Michigan. The corporation shall be entitled to
treat the holder of record of any share or shares of stock as the holder in fact
thereof and accordingly shall not be bound to recognize any equitable or other
claim to or interest in such share on the part of any other person, unless it
shall have express or other notice thereof, or as provided by the laws of the
State of Michigan. The corporation shall have the first lien on all the shares
of the capital stock and upon all dividends declared upon the same for any
indebtedness of the respective holders there notice and proceedings as provided
by statute.

                                     VOTING

      17. Each holder of voting stock of record shall be entitled at every
meeting of the corporation to cast one vote for each share of stock outstanding
in the name of such stockholder and such voting may be cumulative and may be
either by person or by proxy, subject, however, to the limitations, restrictions
and preference as set forth in the Articles of Incorporation, and statutes of
the State of Michigan.


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                     CHECKS, DRAFTS, PROMISSORY NOTES, ETC.

      18. All monies of the corporation other than petty cash shall be disposed
of by check or draft only, same to be executed in the corporation by either the
president or the secretary, or those other officers as the board of directors
may from time to time determine. Promissory notes shall be signed on behalf of
the corporation by the president or secretary, or such other officers as the
directors may from time to time determine. Mortgages and conditional sales
contracts may be executed and assigned by the president or secretary, or such
other officers as the board may from time to time determine.

                                     NOTICE

      19. Whenever under the provisions of these by-laws notice is required to
be given to any director, officer or stockholder, it shall not be construed to
mean personal notice, but such notice may be given in writing by depositing the
same in a post office or letter box in a postpaid sealed wrapper, addressed to
such stockholder, officer or director at such address as appears on the books of
the corporation or in default of other address to such stockholder, officer or
director at such address, to such stockholder at the general post office in the
City of Bay City, Bay County, Michigan, and such notice shall be deemed to have
been given at the time when the same was thus mailed.

                                   FISCAL YEAR

      20. The fiscal year of the corporation shall commence on the first day of
April and end on the 31st day of March, of each year.

                                   AMENDMENTS

      21. These by-laws may not be amended, altered or repealed in any
particular without the affirmative vote of a majority of outstanding voting
stock of the corporation.


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