Document:

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                                                                    Exhibit 10.5
                                                                    ------------

                           COMFORCE OPERATING, INC.

                                  as Issuer,

                                      and

                           WILMINGTON TRUST COMPANY,

                                  as Trustee

                         SECOND SUPPLEMENTAL INDENTURE

                         Dated as of December 4, 2000

                      12% Senior Notes Due 2007, Series A

                      12% Senior Notes Due 2007, Series B

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     SECOND SUPPLEMENTAL INDENTURE, dated as of December 4, 2000 (the
"Supplemental Indenture"), between COMFORCE Operating, Inc., a Delaware
corporation (together with its successors as provided for in the Indenture
referred to below, the "Company"), and Wilmington Trust Company, as Trustee (the
"Trustee"), under an Indenture dated as of November 26, 1997, as previously
amended by the First Supplemental Indenture dated as of November 29, 2000 (as
amended thereby, the "Indenture"), with respect to the 12% Senior Notes due 2007
of the Company.

     Section 9.1(a)(1) of the Indenture provides that, without the consent of
any Securityholder, the Company and the Trustee may amend the Indenture or the
Securities to cure any ambiguity, omission, defect or inconsistency, provided
that such amendment or supplement does not, as evidenced by an Opinion of
Counsel delivered to the Trustee, adversely affect the rights of any
Securityholder in any material respect. The Company and the Trustee are
executing this Supplemental Indenture to amend the definition of "Eligible
Accounts Receivable" in Section 1.1 to cure an ambiguity and inconsistency
contained therein.

                                   ARTICLE I

                                  AMENDMENTS

Section 1.01.  Amendment of Section 1.1 of the Indenture.

     The definition of "Eligible Account Receivable" is amended and restated as
follows:

     "Eligible Account Receivable" means any account receivable, net of any
     prepayments, progress payments, deposits and retentions, owing to the
     Company or any Restricted Subsidiary or to a special purpose entity upon
     assignment thereto by the Company or any Restricted Subsidiary in
     connection with a Securitization, provided that the account meets the
     following specifications:

     (a)  The account is not more than one hundred and twenty (120) days from
          the date of the invoice therefor;

     (b)  The account is not subject to any prior assignment, claim, lien, or
          security interest other than in favor of the Company or any Restricted
          Subsidiary or in connection with a Securitization or the New Credit
          Facility, and the Company or any Restricted Subsidiary will not make
          any further assignment of the account or create any further security
          interest in the account other than in favor of the Company or any
          Restricted Subsidiary or in connection with a Securitization or the
          New Credit Facility, nor permit its rights in the account to be
          reached by attachment, levy, garnishment or other judicial process;

     (c)  The account arose in the ordinary course of the business of, or was
          acquired by, the Company or any Restricted Subsidiary;

     (d)  The account does not arise with respect to an account debtor from whom
          fifty percent (50%) or more of the accounts are more than one hundred
          and twenty days (120) from the date of the invoice therefore; and

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     (e)  No notice of bankruptcy, insolvency or material adverse change of the
          account debtor has been received by or is known to the Company.

                                  ARTICLE II

                                 MISCELLANEOUS

     Section 2.01.  Definitions.  All terms used in this Supplemental Indenture
                    -----------
have the meanings specified in the Indenture unless otherwise defined herein or
unless the context otherwise specifies or requires.

     Section 2.02.  Successors and Assigns.  All the covenants and agreements by
                    ----------------------
the Company contained in this Supplemental Indenture shall bind its successors
and assigns.  All agreements of the Trustee contained in this Supplemental
Indenture binds its successors.

     Section 2.03.  Execution in Counterparts.  This Supplemental Indenture may
                    -------------------------
be executed in any number of counterparts, each of which when so executed shall
be deemed to be an original, but all of which counterparts shall together
constitute one and the same instrument.

     Section 2.04   Governing Law.  This Supplemental Indenture shall be
                    -------------
governed by, and construed in accordance with, the laws of the State of New
York, but without giving effect to applicable principles of conflicts of laws to
the extent that the application of the laws of another jurisdiction would be
required thereby.

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     IN WITNESS WHEREOF, the parties have caused this Supplemental Indenture to
be duly executed as of the date first written above.

                                        COMFORCE OPERATING, INC.

                                        By:_____________________

                                        Name:

                                        Title:

                                        WILMINGTON TRUST COMPANY,
                                        as Trustee

                                        By:______________________

                                        Name:

                                        Title:

                                       4<PAGE>   1
                                                                    EXHIBIT 10.1

                           Second Amended and Restated
                               GUARANTY AGREEMENT

         This agreement is made and entered into as of 1st day of December,
2000, by and between AmerAlia, Inc., a Utah corporation whose address is 818
Taughenbaugh Blvd., Rifle, Colorado 81650 ("AmerAlia") and Jacqueline Mars as
trustee for the Jacqueline Badger Mars Trust, whose address is 6885 Elm Street,
McLean, Virginia 22101 (the "Trust").

                                    RECITALS

A.       AmerAlia has commenced operations necessary to build a plant for the
         production of sodium bicarbonate on property near Rifle, Colorado (the
         "Rock School Project"), and is seeking permanent financing to permit
         the Company to commence construction activities.

B.       AmerAlia has previously borrowed approximately $7,326,000 from the Bank
         of America, N.A. (the "Bank") for working capital purposes and to fund
         an escrow account established in accordance with the requirements of a
         Design/Build Contract entered into between AmerAlia and U.S. Filter
         Wastewater Group, Inc., a Delaware corporation, d/b/a U.S. Filter
         Corporation, HPD Products ("U.S. Filter"), which amounts the Trust has
         previously guaranteed pursuant to a Guaranty Agreement dated September
         13, 1999, a Guaranty Agreement dated January 21, 2000, a Guaranty
         Agreement dated June 30, 2000, and an amended and restated guaranty
         agreement dated as of September 14, 2000; and

C.       AmerAlia is seeking an additional loan of approximately $1,600,000 (the
         "Additional Loan") from the Bank to provide working capital to AmerAlia
         for certain expenses incurred and its continuing operations; and

D.       The Trust and AmerAlia wish to consolidate all existing loans with the
         Bank into a single loan of not more than $9,000,000 (the "Aggregate
         Loan" which includes the Additional Loan); and

E.       The Trust is willing to facilitate the additional loan and the
         Aggregate Loan by guaranteeing the repayment of the loan in a manner
         satisfactory to the Bank provided the Company expends the proceeds of
         the loan only for continuing operations necessary to maintain the
         Company and to permit the Company to complete its negotiations for
         permanent financing necessary to complete the construction of the Rock
         School Project as discussed between officers of the Company and the
         Trust (with the expectation that the funds will not be used for actual
         construction activities); and

F.       AmerAlia is willing to subject the use of the proceeds from the loan to
         such limitations, and to compensate the Trust for providing this
         guarantee.

Guaranty Agreement - AmerAlia, Inc.                                       Page 1
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         NOW, THEREFORE, in consideration of the mutual promises and covenants
contained herein, and for other good and valuable consideration the receipt and
sufficiency whereof is hereby acknowledged, AmerAlia and the Trust agree as
follows:

1.       AmerAlia will execute and deliver to the Bank an application for a loan
         for a period of one year from the date hereof, in an amount no greater
         than $9,000,000 (which amount includes all existing loans between
         AmerAlia and the Bank which have been guarantied by the Trust), the
         proceeds of which will be used for AmerAlia's working capital purposes.

2.       The Trust will execute and deliver to the Bank such forms as may be
         necessary or appropriate to provide a guaranty for the repayment of the
         Aggregate Loan in a form that is satisfactory to the Bank and to the
         Trust, and is consistent with this Agreement (the "Guaranty").

3.       AmerAlia will use the Additional Loan and any additional funds
         available from the Bank pursuant to the Aggregate Loan (the "Loan
         Proceeds") for the following purposes:

         (a)      to pay any interest accrued on the Aggregate Loan through the
                  date hereof to the extent not previously paid;

         (b)      to request advances from time-to-time from the Bank (but not
                  more often than once each calendar month) in amounts not
                  greater than $500,000 pursuant to the following procedure:

                  o        AmerAlia will make a written request to the Bank to
                           withdraw funds pursuant to the loan documents.

                  o        AmerAlia will provide the Trust written notice of the
                           amount requested and a description of the intended
                           use of proceeds as well as AmerAlia's efforts to
                           accomplish Development Arrangements as described in
                           paragraph 4(f), below. AmerAlia will also provide a
                           copy of the written request to the Bank to draw the
                           funds requested from the Aggregate Loan.

                  o        The Bank will advance the funds to AmerAlia at the
                           earlier of: (i) the date the Trust agrees in writing
                           to permit the advance; and (ii) seven days after
                           AmerAlia's written request unless the Trust objects
                           in writing to the advance.

                  o        If the Trust objects in writing to the advance
                           requested by AmerAlia, the Bank will not advance the
                           funds to AmerAlia.

4.       As a condition of the Trust's willingness to enter into this Guaranty
         Agreement and to make the funds to be provided by the Additional Loan
         available to AmerAlia, AmerAlia agrees as follows:

Guaranty Agreement - AmerAlia, Inc.                                       Page 2
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         (a)      AmerAlia will move its corporate offices to Rifle, Colorado,
                  and cease doing business from its offices in Kenilworth,
                  Illinois;

         (b)      AmerAlia will reduce its corporate, general, and
                  administrative expenses (including, without limitation, salary
                  expenses) to the maximum extent possible, with the requirement
                  that compensation to be paid to corporate officers shall be
                  reasonably related to the services they are expected to
                  perform for AmerAlia;

         (c)      AmerAlia hereby grants the Trust as collateral for the
                  repayment of the Aggregate Loan and the Trust's liability
                  under this Guaranty, AmerAlia's entire interest in Natural
                  Soda, Inc., a recently-formed Colorado corporation intended to
                  acquire AmerAlia's entire interest in the Rock School Project
                  and the federal lease associated therewith. The Trust agrees
                  to subordinate its security interest in these assets to any
                  construction financing or long-term financing obtained by
                  AmerAlia in a minimum amount of $20,000,000 on terms that are
                  acceptable to the Board of Directors of AmerAlia;

         (d)      AmerAlia will take such steps as is reasonably necessary or
                  appropriate to permit the transfer of the federal lease to
                  Natural Soda, Inc. and to permit the Trust to own a security
                  interest therein as may be required by the rules and
                  regulations of the Bureau of Land Management in as prompt a
                  period as possible;

         (e)      AmerAlia will take such steps as may be necessary or required
                  to extend the federal lease (which currently expires in June
                  2001) to another renewal term; and

         (f)      AmerAlia will use its best efforts to obtain necessary
                  financing or a strategic alliance for the development of the
                  Rock School Project ("Development Arrangements") as soon as
                  reasonably possible and if during the term of this Agreement
                  it appears that Development Arrangements are not reasonably
                  forthcoming, the Board will determine whether other actions
                  may be in the best interest of the creditors and shareholders
                  of AmerAlia. AmerAlia will make a report to the Trust
                  regarding its progress in achieving a Development Arrangement
                  no later than December 15, 2000 and from time-to-time
                  thereafter as AmerAlia may request further advances pursuant
                  to paragraph 3(b), above. Where the Trust and AmerAlia
                  determine that the progress toward achieving Development
                  Arrangements is insufficient, AmerAlia will determine whether
                  other arrangements may be in the best interests of AmerAlia,
                  its creditors, and its shareholders.

                  o        When used in the foregoing paragraph, the term
                           "necessary financing" means construction financing or
                           permanent financing reasonably sufficient to
                           carry-out AmerAlia's business plan as reviewed by the
                           Trust; and

Guaranty Agreement - AmerAlia, Inc.                                       Page 3
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                  o        When used in the foregoing paragraph, the term
                           "strategic alliance" means a joint venture,
                           partnership, or other business combination with an
                           affiliated or unaffiliated entity which will provide
                           capital or other resources reasonably sufficient for
                           the development of the Rock School Project.

         (g)      AmerAlia will apply the net proceeds of any Development
                  Arrangement, as received, to repay the Aggregate Loan, and the
                  amount of the Guaranty will be reduced to the extent of such
                  repayments. If the Development Arrangement provides for the
                  repayment of the Aggregate Loan in full by no later than
                  February 28, 2001, the Development Arrangement will be
                  "reasonably satisfactory" to the Trust and will meet the
                  requirements of paragraph 4(f).

5.       AmerAlia will pay the Trust compensation for executing and delivering
         the Guaranty to the Bank in an amount equal to 15% of the Aggregate
         Loan, payable in shares of AmerAlia's restricted common stock valued at
         the average closing price as reported by The Nasdaq Stock Market, Inc.
         SmallCap Market for the 30 days following the announcement by AmerAlia
         of the Development Arrangement or the announcement of a determination
         under paragraph 4(f) to pursue other arrangements, but not greater than
         $2.50 per share. If AmerAlia's common stock is not quoted on the Nasdaq
         SmallCap Market during any portion of the 30 days following the
         announcement, the price will be determined by reference to the prices
         quoted on the OTC Bulletin Board (if quoted on the OTC Bulletin Board)
         or as set forth in the National Quotation Bureau sheet listing AmerAlia
         common stock during such period, or (if not publicly traded or quoted
         in any independent source) as may be otherwise determined by the Board
         of Directors in good faith after reviewing all relevant facts and
         circumstances. For example, the Aggregate Loan is $9,000,000 and 15% of
         the Aggregate Loan is $1,350,000; if the average price is $4.25, the
         maximum price to be used to determine compensation to the Trust will be
         $2.50. Consequently, AmerAlia will issue 540,000 shares of restricted
         common stock to the Trust. If, on the other hand, the average price of
         AmerAlia common stock is $1.50 per share, AmerAlia will issue 900,000
         shares of its restricted common stock to the Trust as full compensation
         for this Guaranty. The shares will be issued to the Trust within three
         business days of this determination.

6.       If the Trust makes any payment to the Bank under the Guaranty, AmerAlia
         will indemnify and hold the Trust harmless for any such payment, and
         for all other costs and expenses, including reasonable attorneys' fees
         incurred in connection therewith.

7.       The Trust acknowledges that such shares, when issued, will be
         restricted as that term is defined in Rule 144 of the Rules and
         Regulations promulgated by the Securities and Exchange Commission. The
         Trust further acknowledges, represents and warrants to AmerAlia that:

Guaranty Agreement - AmerAlia, Inc.                                       Page 4
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         (a)      The Trust is an 'accredited investor' as that term is defined
                  in Section 2(a)(15) of the Securities Act of 1933 (the "1933
                  Act") and Rule 215 thereunder, and in Rule 501(a) of
                  Regulation D of the 1933 Act.

         (b)      AmerAlia has given the Trust and its legal, financial, tax,
                  and investment advisors the opportunity to ask questions of
                  and to receive answers from persons acting on AmerAlia's
                  behalf concerning the terms and conditions of this transaction
                  and the opportunity to obtain any additional information
                  regarding AmerAlia, its business and financial condition which
                  AmerAlia possesses or can acquire without unreasonable effort
                  or expense including (without limitation) all minutes of the
                  meetings of the Board of Directors of AmerAlia or committees
                  thereof, and other relevant documents requested by the Trust.
                  In addition, the Trust has spoken with the independent
                  auditors for AmerAlia and has made financial or other
                  inquiries as the Trust or its advisors have deemed necessary
                  or appropriate in the conduct of the Trust's due diligence
                  investigation.

         (c)      The Trust acknowledges and understands that, although there is
                  currently a market for AmerAlia's common stock, the market is
                  dependent on a number of factors beyond the control of
                  AmerAlia and may not continue. Furthermore the Trust
                  acknowledges that although AmerAlia believes that it is in
                  compliance with all requirements for continued listing of the
                  Common Stock on the Nasdaq SmallCap Market, continued listing
                  on the Nasdaq SmallCap Market is subject to a number of
                  objective and subjective criteria. Although AmerAlia believes
                  it is in material compliance with all objective criteria,
                  there can be no assurance that the staff of the Nasdaq
                  SmallCap Market may not reach a different conclusion or that
                  the Nasdaq staff may not reach a conclusion that AmerAlia is,
                  for some reason, not in compliance with subjective criteria
                  which is not specified in the rules applicable to the Nasdaq
                  SmallCap Market.

         (d)      The Trust understands that the securities being acquired
                  hereby are and will continue to be restricted securities
                  within the meaning of Rule 144, and applicable state statutes.
                  The Trust consents to the placement of an appropriate
                  restrictive legend or legends on any certificates evidencing
                  the securities and any certificates issued in replacement or
                  exchange therefor and acknowledges that AmerAlia will cause
                  its stock transfer records to note the restrictions.

                  o        The Trust must bear the economic risks of the
                           investment in the securities for an indefinite period
                           of time because they have not been registered under
                           the 1933 Act or any state securities laws;

                  o        As "restricted securities" (unless registered for
                           resale or another exemption from registration is
                           available for any transfer), the securities must be
                           held for a minimum of one year following the
                           purchase. Thereafter, the securities may be sold in
                           only limited amounts in a specified manner in

Guaranty Agreement - AmerAlia, Inc.                                       Page 5
<PAGE>   6

                           accordance with the terms and conditions of Rule 144
                           (the "Rule") if the Rule is applicable (there being
                           no representation by AmerAlia that it will be
                           applicable). In case the Rule is not applicable, any
                           sales may be made only pursuant to an effective
                           registration statement or an available exemption from
                           registration.

                  o        The securities cannot be sold unless they are
                           registered under the 1933 Act and any applicable
                           state securities laws or unless an exemption from the
                           registration requirements is available. To the extent
                           that AmerAlia files any registration statement under
                           the 1933 Act (not including a registration statement
                           on Form S-4, S-8, S-11, or other inappropriate form),
                           AmerAlia will endeavor to include the Securities in
                           such registration statement, subject to any
                           requirements that may be imposed by any underwriter
                           named in the registration statement (which
                           requirements may include, but are not limited to, a
                           delay in the ability of the selling security holder
                           to sell the shares, a requirement that any sales be
                           made through the underwriter, or a prohibition on any
                           sales by the selling security holder pursuant to the
                           registration statement in certain specified
                           circumstances, in the underwriter's sole discretion).

         (e)      The Trust has reviewed the terms of this agreement and the
                  transaction contemplated by this agreement with its legal,
                  investment, tax, and financial advisors to the extent the
                  Trust has deemed such consultation appropriate. The Trust has
                  also consulted with such advisors with regard to the
                  advisability of this investment to the extent the Trust has
                  deemed such consultation to be appropriate. The Trust
                  acknowledges that AmerAlia has advised the Trust that it
                  recommends that the Trust obtain advice and consultation. The
                  Trust further acknowledges that it has neither sought nor
                  received any advice from AmerAlia or any of its agents or
                  affiliates with respect to any aspect of this Agreement.

         (f)      The Trust acknowledges that the investment contemplated herein
                  is one of significant risk, and there can be no assurance that
                  the securities will ever be valuable. The Trust hereby
                  represents that the investment in the securities is a suitable
                  investment for it, taking into consideration the restrictions
                  on transferability and the other considerations affecting the
                  securities and AmerAlia as described herein and in AmerAlia's
                  reports filed with the Securities and Exchange Commission
                  pursuant to the Securities Exchange Act of 1934, as amended
                  (the "1934 Act").

         (g)      The Trust acknowledges that the acquisition of the securities
                  as contemplated herein will impose certain reporting
                  obligations on the Trust pursuant to Sections 13(d) and 16(a)
                  of the 1934 Act, and may impose certain obligations under the
                  Internal Revenue Code of 1986, as amended. The Trust will make
                  all necessary filings.

Guaranty Agreement - AmerAlia, Inc.                                       Page 6
<PAGE>   7

8.       All prior agreements for the Trust's guaranty of any portion of the
         Aggregate Loan (including, without limitation, the agreements described
         in Recital B, above) be and hereby are terminated. The Trust and
         AmerAlia affirmatively state and agree that no compensation has been
         paid under any prior agreement, and none is currently payable because
         (although the Trust has performed its obligations under the prior
         guaranties) all of the conditions precedent to payment have not been
         met. The compensation payable by AmerAlia for the Trust's guaranty of
         the Aggregate Loan pursuant to this Guaranty Agreement and all prior
         guaranty agreements relating to any portion of the Aggregate Loan will
         be determined by this Guaranty Agreement.

9.       All notices under this Agreement are to be delivered by (i) depositing
         the notice in the mail, using registered mail, return receipt
         requested, addressed to the address below or to any other address as
         the party may designate by providing notice, (ii) telecopying the
         notice by using the telephone number set forth below or any other
         telephone number as the party may designate by providing notice, (iii)
         overnight delivery service addressed to the address below or to any
         other address as the party may designate by providing notice, or (iv)
         hand delivery to the individual designated below or to any other
         individual as the party may designate by providing notice. The notice
         shall be deemed delivered (i) if by registered mail, four (4) days
         after the notice is deposited in the mail, (ii) if by telecopy, on the
         date the notice is delivered, (iii) if by overnight delivery service,
         on the date of delivery, and (iv) if by hand delivery, on the date of
         delivery.

                  If to AmerAlia, to the address set forth in the first
                  paragraph hereof (telecopy number 879-625-9137), with a copy
                  (which does not constitute notice) to:

                           Nortono Lidstone, P.C.
                           Suite 850, The Quadrant
                           5445 DTC Parkway
                           Englewood, CO 80111
                           Attn: Herrick K. Lidstone, Jr., Esq.
                           Telecopy: 303-221-5553

                  If to the Trust, to the attention of David Newby (telecopy
                  number) 703-519-7075) at the address set forth in the first
                  paragraph hereof, with a copy (which does not constitute
                  notice) to:

                           Hills & Stern
                           1200 Nineteenth Street, N.W.
                           Washington, D.C. 20036
                           Attn: Roderick M. Hills, Esq.
                           Telecopy: 202-822-1622

Guaranty Agreement - AmerAlia, Inc.                                       Page 7
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10.      General Provisions

         (a)      Complete Agreement. The parties agree that this Agreement is
                  the complete and exclusive statement of the agreement between
                  the parties, which supersedes and merges all prior proposals,
                  understandings and all other agreements, oral or written,
                  between the parties relating to this Agreement.

         (b)      Amendment. This Agreement may not be modified, altered or
                  amended except by written instrument duly executed by both
                  parties.

         (c)      Waiver. The waiver or failure of either party to exercise in
                  any respect any right provided for in this Agreement shall not
                  be deemed a waiver of any further right under this Agreement.

         (d)      Severability. If any provision of this Agreement is invalid,
                  illegal or unenforceable under any applicable statute or rule
                  of law, it is to that extent deemed omitted. The remainder of
                  the Agreement shall be valid and enforceable to the maximum
                  extent possible.

         (e)      Governing Law. This Agreement and performance hereunder shall
                  be governed by the laws of the State of Colorado.

Each party acknowledges that it has read and understands this Agreement and
agrees to be bound by its terms.

AmerAlia, Inc.                         The Jacqueline Badger Mars Trust

By: /s/ Bill H. Gunn                   By: /s/ Jacqueline Mars
   -----------------                      --------------------
Bill H. Gunn, President                   Jacqueline Mars, Trustee

Guaranty Agreement - AmerAlia, Inc.                                       Page 8

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