<PAGE>

                                                                   Exhibit 10(b)
 
                    FIRST AMENDMENT TO EMPLOYMENT AGREEMENT
                    ---------------------------------------



         THIS AGREEMENT made as of September 15, 1997, between HERITAGE BANCORP,
INC., a Pennsylvania corporation formerly known as Miners National Bancorp, Inc.
("Employer"), having an office at 120 South Centre Street, Pottsville,
Pennsylvania 17901, and RICHARD A. KETNER, with an address at 118 Avenue E,
Schuylkill Haven, Pennsylvania 17972 ("Executive").

                              W I T N E S S E T H:

         WHEREAS, Executive and Employer are parties to that certain Employment
Agreement dated as of September 13, 1994 pursuant to which Executive has been
employed as Executive Vice President of Employer and Heritage National Bank
(formerly The Miners National Bank), a wholly-owned subsidiary of Employer (the
"Bank"); and

         WHEREAS, Employer and Executive desire to extend the terms of said
Employment Agreement and make certain other amendments as set forth herein.

         NOW, THEREFORE, in consideration of the mutual promises set fort herein
and in said Employment Agreement and intending to be legally bound, the parties
hereto hereby agree as follows:

         1. The "Term" of Executive's employment under said Employment Agreement
(said Employment Agreement as amended hereby is hereinafter referred to as the
"Employment Agreement") as provided in Section 2(a) is hereby extended until
September 30, 2000 and all references in the Employment Agreement to the Term
shall include the Term as extended hereby.
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         2. The first sentence of Section 2(b) of the Employment Agreement is
hereby amended to read as follows: "Executive's employment right hereunder shall
automatically terminate at the close of business on September 30, 2000."

         3. Executive's annual base salary during the remainder of the Term
shall be at least equal to executive's base salary currently in effect, subject
to increase by Employer from time to time with the approval of the Board of
Directors of Employer.

         4. Section 6(c) of the Employment Agreement is hereby amended to read
as follows:

            (c) Other Benefits. Executive acknowledges that, in the event of
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    termination of Executive's employment during the Term of his employment
    hereunder pursuant to paragraph (a) of this Section 6, the payments and
    benefits to be made or provided to Executive pursuant to this Section 6 are
    to be in full satisfaction of Employer's obligations to Executive under this
    Employment Agreement and Executive shall not be entitled to any other
    severance or termination benefits, whether pursuant to this Employment
    Agreement or otherwise; provided, however, that this paragraph (c) shall not
                            --------  -------
    be deemed to affect Executive's rights to payments or benefits under any
    existing or future benefit plan or arrangement (other than a severance or
    termination plan or arrangement) of the Corporation, the Bank or any
    successor in which Executive is or becomes a participant, or under which
    Executive has or obtains rights, including, without limitation, any
    qualified or nonqualified deferred compensation or retirement plans or
    programs or any outstanding stock options or similar agreements. Any such
    rights of Executive shall be determined in accordance with the terms and
    conditions of the applicable agreement, arrangements or plan and applicable
    law. Notwithstanding the foregoing, if during the Term Executive becomes
    entitled to receive benefits under any change in control agreement then in
    effect as a result of the termination of Executive's employment following a
    change in control event specified in said agreement, the benefits to be
    provided under such change in control agreement shall control and Executive
    shall not be entitled to also receive termination benefits under this
    Employment Agreement.

         5. Section 7 of the Employment Agreement is hereby amended by deleting
it in its entirety.

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         6. The terms of the Employment Agreement dated September 13, 1994, as
amended hereby, shall remain in full force and effect from and after the date
hereof.

         IN WITNESS WHEREOF, the following have caused their signatures and
seals to be hereunto affixed to this Amendment as of the date first above
written.

ATTEST:                                HERITAGE BANCORP, INC.


/s/  Beverly A. Riotto                 By: /s/  Allen E. Kiefer
-----------------------------             ---------------------------------
(Assistant) Secretary
(SEAL)



WITNESS:                                EXECUTIVE


/s/  David L. Scott                     /s/  Richard A. Ketner            (SEAL)
---------------------------             ----------------------------------
                                        Richard A. Ketner


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