Document:

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                                                                   EXHIBIT 10.18

                                                                  Execution Copy

                                      NOTE
                                (NON-NEGOTIABLE)

$817,800                                                Pittsburgh, Pennsylvania
                                                               December 29, 2000

   FOR VALUE RECEIVED and intending to be legally bound hereby, the
undersigned, Richard A. Byers, an individual ("Maker"), hereby unconditionally
promises to pay PITT-DES MOINES, INC., a Pennsylvania corporation ("PDM"), in
immediately available funds, the principal sum of eight hundred seventeen
thousand eight hundred dollars ($817,800), together with interest at a rate
equal to the greater of (1) the rate charged to PDM under its senior credit
facility from time to time or (2) the Applicable Federal Short-Term per annum
interest rate, as published by the Internal Revenue Service from time to time,
calculated on the basis of a 360 day calendar year and 30 day month for
prorating the calculation of interest, on the dates and in the manner set forth
herein. The aforesaid interest rate shall continue to apply whether or not
judgment shall be entered on this Note.

   The principal balance and any accrued interest under this Note shall be due
in a single lump sum on the date of consummation (in a single transaction or
series of related transactions) of the sale of all or substantially all (more
than 50%) of the common stock, no par value, of PDM whether by tender offer,
merger or otherwise. All payments of principal and interest shall be made in
United States currency. If any payment or action to be made or taken hereunder
shall be stated to be or become due on a Saturday, Sunday or on any other day
which is a legal bank holiday under the laws of the Commonwealth of
Pennsylvania, such payment or action shall be or become due on the next
succeeding business day and such extension of time shall be included in
computing interest in connection with such payment.

   Maker shall be in default under this Note upon the happening of any of the
following events of default (each being referred to herein as an "Event of
Default"): (a) default in the payment within three (3) business days of the due
date of any principal or interest on this Note; or (b) insolvency, appointment
of a receiver of any part of the property of, assignment for the benefit of
creditors by or the commencement of proceedings under any bankruptcy or
insolvency laws by or against Maker or any guarantor or surety of any of the
obligations of Maker, for so long as such proceedings or appointment are not
reasonably contested in good faith by Maker.

   Upon the occurrence of any Event of Default under subparagraph (a) of the
preceding paragraph, PDM may declare the outstanding principal amount of this
Note, together with all accrued and unpaid interest thereon to be immediately
due and payable and the same shall thereupon become immediately due and payable
without any further action on the part of PDM. Upon the occurrence of any Event
of Default under subparagraph (b) of the preceding paragraph, the outstanding
principal amount of this Note, together with all accrued and unpaid interest
thereon shall be immediately due and payable and the same shall thereupon
become immediately due and payable without any further action on the part of
PDM. If the principal of this Note or any portion hereof and, to the extent
permitted by law, interest hereon shall not be paid when due, whether by
acceleration or otherwise, the same shall bear interest for any period during
which the same shall be overdue at a rate per annum equal to the Default Rate,
and payable on demand. "Default Rate" means a rate of interest that is three
percentage points above the prime lending rate being charged by PNC Bank, N.A.
in Pittsburgh, Pennsylvania.

   Maker shall have the right at any time to prepay all, or any part of, the
principal amount of this Note without prepayment premium or penalty of any
kind.

   Maker shall have no off-set rights against amounts due under this Note for
claims against PDM.
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   Maker waives demand, presentment for payment, notice of dishonor, protest
and notice of protest and diligence in collection and bringing suit and the
holder hereof may extend the time for payment or accept partial payment without
discharging or releasing Maker.

   This Note shall bind Maker and the heirs, personal representatives,
successors and assigns of Maker, and the benefits hereof shall inure to the
benefit of PDM and its successors and assigns. All references herein to "Maker"
shall be deemed to apply to Maker and to the heirs, personal representatives,
successors and assigns of Maker, and all references herein to "PDM" shall be
deemed to apply to PDM and its successors and assigns.

   This Note and any other documents delivered in connection herewith and the
rights and obligations of the parties hereto and thereto shall for all purposes
be governed by and construed and enforced in accordance with the substantive
law of the Commonwealth of Pennsylvania without giving effect to conflict of
laws principles.

   IN WITNESS WHEREOF, Maker, intending to be legally bound, has executed this
Note on the day and year first above written with the intention that this Note
shall constitute a sealed instrument.

WITNESS:

-------------------------------------
                                          -------------------------------------
                                          Richard A. Byers

                                       2<PAGE>

                                                                   EXHIBIT 10.19

                              SEPARATION AGREEMENT

     It is hereby agreed by and between ROBERT J. BENSH ("Employee") and
BELLWETHER EXPLORATION COMPANY ("Bellwether"), that Employee has voluntarily
resigned from his position as Senior Vice President - Finance effective January
1, 2001; provided, however, Employee shall remain an employee of Bellwether
until his resignation of employment becomes effective on or before June 1, 2001
(hereinafter "Separation Date"), and that in order to resolve amicably all
matters concerning his employment and release, Employee and Bellwether, in
consideration of their mutual promises and other consideration itemized below,
hereafter enter into the following agreements:

     1.  Nothing stated in this Agreement, or stated or done in connection
herewith, shall constitute or indicate in any way any wrongdoing of any kind
either by Employee or Bellwether.

     2.  Bellwether and Employee are parties to that certain Employment
Agreement entered into effective as of June 1, 2000 ("Employment Agreement").
Bellwether agrees that upon execution by Employee and receipt by its
representative of this Agreement and the Mutual Release appended as EXHIBIT A,
the Employment Agreement is terminated pursuant to Section 5(e) of the
Employment Agreement and the Employee shall not be entitled to any further
compensation other than any unpaid Salary and benefits accrued through the date
of termination; provided, however, Employee shall receive the following:

          (a) Current salary and benefits for Employee for a ninety (90) day
     period subsequent to the date of this Agreement. Such salary payment shall
     be made to the personal bank account of Robert J. Bensh;

          (b) Salary and benefits for Employee's assistant, Dana Dupriest,
     ("Assistant") for a ninety (90) day period;

          (c) Use of the following until June 1, 2001:  (i) office space for
     Employee and Assistant at the Company's Houston, Texas offices, (ii)
     furniture, (iii) telephone service, (iv) computer equipment and (v)
     necessary office supplies;

          (d) All of Employee's Company stock options shall immediately vest as
     of the date hereof and Employee shall have the right to exercise said stock
     option on or before the close of business on June 30, 2002;

          (e) One-half of the Houston Astro field box season tickets at Enron
     Field for the 2001 season only on the following basis:

             Odd-numbered games - Employee
             Even-numbered games - Bellwether

     Thereafter, the season tickets revert back to the Employee as previously
     stated in the Employee's original Employment Agreement entered into with
     the Company.
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     3.  Effective June 1, 2001, Employee acknowledges that during the course of
his employment, he has had access to certain trade secrets of Bellwether and
that such trade secrets constitute valuable, highly confidential, special and
unique property of Bellwether, which Employee agrees not to disclose.  These
"trade secrets" are maps, computer programs, engineering studies, geological
studies, and files, records and documents relating thereto.  Also, the "trade
secrets" include lists of customers who utilize Bellwether's services, related
customer information and the internal financial statements and related
information of Bellwether.  However, such customer lists do not include
customers which Employee knew before he was employed by Bellwether; neither do
such customer lists include customers which could readily be identified by
someone outside the employ of Bellwether.  These "trade secrets" shall not
include any information readily discernable from trade or general circulation
publications or otherwise existing or available in public domain.

     4.  Effective June 1, 2001, Employees of Bellwether shall refrain from
making any derogatory or disparaging remarks to any third party against Employee
with respect to his employment by Bellwether, his performance, his character, or
any such matters.  Further, employees of Bellwether shall refrain from
discussions among themselves using any such derogatory or disparaging remarks.
In compliance with the covenant, Bellwether's obligation shall be to make
reasonable efforts to have its employees refrain from making the type or remarks
described in this last paragraph.  Management shall instruct any employees
overheard to make such remarks to cease and desist.

     5.  Effective June 1, 2001, Employee shall refrain from making any
derogatory or disparaging remarks regarding his employment by Bellwether, or
Bellwether's services, management, or operations to any third party other than
members of Employee's immediate family.

     6.  Effective June 1, 2001, Employee acknowledges that he has been given a
period of up to twenty-one (21) days within which to consider this Agreement and
the Mutual Release to be executed hereunder, and that these documents have been
executed by him voluntarily prior to expiration of the 21-day period, with full
knowledge of all relevant information and after ample opportunity to consult
with legal counsel.  Employee is hereby advised to consult with and represents
that he has consulted with an attorney prior to entering into this Agreement and
the Mutual Release to be executed hereunder.  Employee and Bellwether further
agree that Employee has a period of seven (7) days following his execution of
this Agreement and the Mutual Release to be executed hereunder in which to
revoke these documents by delivering to Bellwether's undersigned representative
written notice of his revocation, and that this Agreement and the Mutual Release
executed hereunder shall not become effective or enforceable until such
revocation period has expired.

     7.  Effective June 1, 2001, Bellwether and Employee agree that they will
not disclose to any other person or entity and will keep confidential the fact
of the existence of this Agreement, and all other facts or information of every
kind concerning this Agreement.  Provided, however, that Employee may disclose
the existence of this Agreement or information

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therein to his family, his attorney(s) or to his financial advisors or tax
preparer or to the government for tax purposes, or as otherwise required by law.

     8.  This Agreement shall be binding on and inure to the benefit of Employee
and Bellwether as well as all of their heirs, executors, administrators,
officers, directors, employees, stockholders, successors and assigns, and all
subsidiaries, affiliates and representatives of any of the foregoing entities.

     9.  Bellwether and Employee agree that this Agreement and the Mutual
Release shall be construed under the laws of Texas and, if necessary, litigated
in Houston, Texas.

     10.  This Agreement contains the entire agreement of the parties in
complete satisfaction of all claims Employee or Bellwether may have against each
other as of the date of execution of this Agreement, including all accrued costs
and fees, if any.  This Agreement may be executed in one or more counterparts,
all of which together shall constitute a single instrument.

     IN WITNESS HEREOF, the parties to this Agreement have executed this
instrument on the dates set forth below.

                                             EMPLOYEE:

Date:
     -------------------------------         --------------------------------
                                             Robert J. Bensh

                                             BELLWETHER EXPLORATION
                                             COMPANY

Date:                                        By:
     -------------------------------            --------------------------------
                                                Douglas G. Manner, President

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