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                                                                EXHIBIT 10(12.1)

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                                                                EXHIBIT 10(12.1)

                                 FIRST AMENDMENT

         THIS FIRST AMENDMENT (this "First Amendment") dated as of December 5,
1997 is to the Amended and Restated Credit Agreement (the "Credit Agreement")
dated as of July 25, 1997 among LAYNE CHRISTENSEN COMPANY (the "Company"), LAYNE
CHRISTENSEN AUSTRALIA PTY LIMITED ("Layne Australia"), various financial
institutions and BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION, as
Agent (in such capacity, the "Agent"). Unless otherwise defined herein, terms
defined in the Credit Agreement are used herein as defined therein.

         WHEREAS, the parties hereto have entered into the Credit Agreement
which provides for (i) the Banks to make U.S. Loans to the Company from time to
time, (ii) the Australian Banks to make Australian Loans to Layne Australia from
time to time, and (iii) the Issuer to issue Letters of Credit for the account of
the Company (or jointly for the account of the Company and any Subsidiary) from
time to time and for the Banks to purchase participations therein; and

         WHEREAS, the parties hereto desire to amend the Credit Agreement to add
two additional financial institutions as Australian Banks;

         NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration (the receipt and sufficiency of which are hereby
acknowledged), the parties hereto agree as follows:

         SECTION 1. NEW AUSTRALIAN BANKS. Effective on and as of the First
Amendment Effective Date (as defined below), each of Bank of New Zealand
Australia, A Division of National Australia Bank Limited ACN 004 044 937 and
Societe Generale Australia Limited ACN 002 093 021 shall be added as a party to
the Credit Agreement as an Australian Bank with an Australian Percentage as set
forth on Schedule 1.1(a) to the Credit Agreement, as amended hereby, and shall
have all of the rights and obligations of an Australian Bank under the Credit
Agreement, as amended hereby. The address for each new Australian Bank is set
forth below its signature hereto.

         SECTION 2. AMENDMENT. Effective on (and subject to the occurrence of)
the First Amendment Effective Date, the Credit Agreement shall be amended as set
forth in SECTIONS 2.1 AND 2.2 below.

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         SECTION 2.1 SECTION 1. The definition of "Note" in Section 1 of the
Credit Agreement is hereby amended by deleting the language "Section 3.1"
therein and substituting therefor the language "Section 3.2".

         SECTION 2.2 SECTION 3. Section 3 of the Credit Agreement is hereby
amended in its entirety to read as follows:

                    SECTION 3  NOTES AND LOAN ACCOUNTS.

                    3.1 LOAN ACCOUNT. The Loans made by each Bank shall be
         evidenced by one or more accounts or records maintained by such Bank in
         the ordinary course of business. The accounts or records maintained by
         the Agent and each Bank shall be rebuttable presumptive evidence of the
         amount of the Loans made by the Banks to the Borrowers, and the
         interest and payments thereon. Any failure so to record or any error in
         so recording shall not, however, limit or otherwise affect the
         obligation of the applicable Borrower hereunder to pay any amount owing
         with respect to any Loan.

                    3.2 NOTES. Upon the request of any Bank made through the
         Agent (and in the case of Australian Loans, so long as the issuance of
         such Note shall not result in the imposition of any stamp, withholding
         or other tax), the Loans made by such Bank to either Borrower may be
         evidenced by a promissory note (as amended, supplemented, replaced or
         otherwise modified from time to time, individually each a "Note" and
         collectively for all Banks the "Notes") substantially in the form of
         EXHIBIT A, instead of loan accounts. Each such Bank shall endorse on
         the schedules annexed to the applicable Note the date, amount and
         maturity of each applicable Loan made by it and the amount of each
         payment of principal made by such Borrower with respect thereto. Each
         such Bank is irrevocably authorized by such Borrower to endorse the
         applicable Note and each such Bank's record shall be conclusive absent
         demonstrable error; PROVIDED, HOWEVER, that the failure of a Bank to
         make, or an error in making, a notation on any Note with respect to any
         Loan shall not limit or otherwise affect the obligations of the such
         Borrower hereunder or under such Note to such Bank.

         SECTION 2.3 Schedule 1.1(a). Schedule 1.1(a) to the Credit Agreement is
amended in its entirety to read in the form of SCHEDULE 1.1(a) hereto.

         SECTION 3. EFFECTIVENESS. The provisions set forth in SECTIONS 1 and 2
above shall become effective, as of the day and year first above written, on
such date (the "First Amendment Effective Date") that the Agent shall have
received counterparts of this First Amendment executed by the parties hereto.

                                      -2-

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         SECTION 4.  MISCELLANEOUS.

         SECTION 4.1 CONTINUING EFFECTIVENESS, ETC. As herein amended, the
Credit Agreement shall remain in full force and effect and is hereby ratified
and confirmed in all respects.

         SECTION 4.2 COUNTERPARTS. This First Amendment may be executed in any
number of counterparts and by the different parties on separate counterparts,
and each such counterpart be deemed to be an original but all such counterparts
shall together constitute one and the same First Amendment.

         SECTION 4.3 GOVERNING LAW. This First Amendment shall be a contract
made under and governed by the internal laws of the State of Illinois.

         SECTION 4.4 SUCCESSORS AND ASSIGNS. This First Amendment shall be
binding upon the Company, Layne Australia, the Banks and the Agent and their
respective successors and assigns, and shall inure to the benefit of the
Company, Layne Australia, the Banks and the Agent and the successors and assigns
of the Banks and the Agent.


                                      -3-

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         Delivered at Chicago, Illinois, as of the day and year first above
written.


                             LAYNE CHRISTENSEN COMPANY


                             By: /s/ Jerry W. Fanska
                                ---------------------------------------------
                             Title: Vice President-Finance
                                   ------------------------------------------



                              LAYNE CHRISTENSEN AUSTRALIA PTY LIMITED
                                    ACN 078 167 610


                              By: /s/ A. B. Schmitt
                                ---------------------------------------------
                              Title:    Director
                                   ------------------------------------------



                               BANK OF AMERICA NATIONAL TRUST AND SAVINGS 
                                    ASSOCIATION,
                                    as Agent


                             By: /s/ R. G. Stapleton
                                ---------------------------------------------
                                        Managing Director



                             BANK OF AMERICA NATIONAL TRUST AND SAVINGS 
                             ASSOCIATION, as a Bank


                             By: /s/ R. G. Stapleton
                                ---------------------------------------------
                                        Managing Director


                             BA AUSTRALIA LIMITED ACN 004 617 841


                             By: /s/ R. G. Stapleton
                                ---------------------------------------------
                                        Attorney in Fact


                                      -4-

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                              MERCANTILE BANK, as Co-Agent and
                              as a Bank


                              By: /s/ Brian Hoban
                                ---------------------------------------------
                              Title:  Corporate Banking Officer
                                   ------------------------------------------



                              MICHIGAN NATIONAL BANK, as Co-Agent and as a Bank


                              By: /s/ Christopher J. Mayone
                                ---------------------------------------------
                              Title: Commercial Relationship Manager
                                   ------------------------------------------



                              BANK OF NEW ZEALAND AUSTRALIA, A
                              DIVISION OF NATIONAL AUSTRALIA BANK
                              LIMITED ACN 004 044 937


                              By: /s/ Mark Yarwood
                                ---------------------------------------------
                              Title: Head of Business Banking
                                    -----------------------------------------

                              Level 6, 395 Collins Street
                              Melbourne, Victoria
                              Australia
                              Attention:  Janine Anderiesz
                              Facsimile:  (61) (03) 9641-4600


                             THE BANK OF NOVA SCOTIA


                              By: /s/ F.C.H. Ashby
                                ---------------------------------------------
                              Title:  Senior Manager Loan Operations
                                    -----------------------------------------
  



                             SOCIETE GENERALE - CHICAGO BRANCH


                             By: /s/ Robert W. Bolt
                                ---------------------------------------------
                             Title: Vice President
                                   ------------------------------------------


                                      -5-

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                                 SOCIETE GENERALE AUSTRALIA LIMITED
                                 ACN 002 093 021


                                 By:  /s/  Yannick Chagnon
                                ---------------------------------------------
                                 Title:  Managing Director
                                       --------------------------------------

                                 350 George Street
                                 Sydney NSW
                                 Australia
                                 Attention:  Michel Vimal du Monteil
                                 Facsimile:  612 9235 3941


                                      -6-

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                                 SCHEDULE 1.1(A)

                        COMMITMENT LIMITS AND PERCENTAGES





                                               Amount of                                            Australian
Name of Bank                                   Commitment                       Percentage          Percentage
- ------------                                   ----------                       ----------          ----------

                                                                                                 
Bank of America National                         U.S.$25,000,000                    25.0%                 N/A
Trust and Savings Association

BA Australia Limited*                                N/A                            N/A                   40%

Mercantile Bank                                  U.S.$20,000,000                    20.0%                 N/A

Michigan National Bank                           U.S.$20,000,000                    20.0%                 N/A

Bank of New Zealand Australia,                       N/A                            N/A                   32%
 A Division of National
 Australia Bank Limited*

The Bank of Nova Scotia                          U.S.$17,500,000                    17.5%                 N/A

Societe Generale-Chicago                         U.S.$17,500,000                    17.5%                 N/A
 Branch

Societe Generale Australia                             N/A                          N/A                   28%
 Limited*
                                                ----------------                   ------               -----
TOTALS                                          U.S.$100,000,000                     100%                100%

* Designated as an Australian Bank by the Bank listed immediately above such
Australian Bank.





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