Document:

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                       [BACKWEB TECHNOLOGIES LETTERHEAD]

                                                                   EXHIBIT 10.20

                              BackWeb Confidential

                                                                    July 3, 2002

MICHAEL A. MORGAN
230 South Peter Drive
Campbell CA 95008

Dear Mike,

On behalf of BackWeb Technologies (the "Company"), we are delighted to present
to you an offer for the position of Chief Financial Officer. In this position,
you will report to the Chief Executive Officer and is anticipated that your
start date shall be on or before August 20, 2002.

Current Compensation
--------------------

Your initial salary will be $7,916.66 twice a month (equivalent to $190,000 on
an annual basis) less all required withholding taxes and Social Security. In
addition, you will receive an annual bonus of $80,000 (less all required
withholding taxes and Social Security) provided that you will meet 100% of your
plan. The 2002 bonus will be constructed: 50% MBO and 50% according to corporate
goals.
The bonus allocation will be modified from year to year based on company needs.
The bonus will be paid at the end of the fiscal year.

In addition, you will also receive a competitive benefit package that will
include a vacation package, medical plan, dental plan, vision plan, life
insurance, long term disability insurance and 401k (non-matching).

Subject to the terms of this letter, BackWeb Technologies may modify
compensation and benefits from time to time, as it deems necessary.

Stock Option
------------

BackWeb Technologies is also very pleased to offer you employee stock options
under the terms of our employee Stock Option Plan. Your options, subject to
approval by the Board of Directors, will be for 250,000 shares.

So long as you are employed by the company, the options will vest at a rate of
25% on the first anniversary of your employment date, and month to month
thereafter for a period of 3 years.
<PAGE>

In the event the company is acquired by merger, consolidation, or assets sell
and a comparable position is not available to you in the new combined company,
the initial cliff term will be waived and all of your options will be vested at
the time of the closing. The remainder of your non-vested options provided in
this offer will be automatically vested at the time of the closing.

Your option package and all of its terms require approval of the BackWeb board.

Vacation Days
-------------

You will be entitled to 17 vacation days per one year of service. You will also
be entitled to all local holidays per the Company policy.

Proprietary Information
-----------------------

BackWeb Technologies is very impressed with the experience and skills that you
will bring to us and hope you will seriously consider this offer. Should you
accept this offer, you will also be asked to review and to sign our standard
Proprietary Information and Inventions Agreement.

We are looking forward to a long and mutually beneficial relationship.

                                    Sincerely,

                                    Eli Barkat
                                    Chief Executive Officer

I understand the above and accept this offer of employment in accordance with
the above terms.

By:  /s/ MICHAEL A. MORGAN
     ----------------------
     Mike Morgan

     7/12/02
     ----------------------
     Date<PAGE>

                                                                  EXHIBIT 10.8.1

                              EMPLOYMENT AGREEMENT

         THIS EMPLOYMENT AGREEMENT, effective as of the______ day of May, 2003
(the "Agreement"), by and between UNITED STATES LIME & MINERALS, INC., a Texas
corporation (herein, together with its successors and permitted assigns,
"Employer") and TIMOTHY W. BYRNE ("Employee").

                                   WITNESSETH

         WHEREAS, Employee has been employed by Employer pursuant to an
agreement dated as of December 8, 2000;

         WHEREAS, Employer and Employee have agreed to amend and restate their
agreement as set forth herein; and

         WHEREAS, Employer desires to continue to employ Employee, and Employee
desires to continue to be so employed, on the terms and conditions hereinafter
set forth;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants herein contained, Employer and Employee hereby agree as follows:

         1.       Employment.

                  (a)      Employer hereby employs Employee to serve, subject to
the supervision and control of Employer's Board of Directors (the "Board"), as
Employer's President and Chief Executive Officer ("CEO"), and to undertake and
discharge, in accordance with the terms and conditions of this Agreement, such
duties, functions, and responsibilities for Employer and its subsidiaries as are
from time to time assigned to Employee by the Board.

                  (b)      Employer hereby agrees to use its best efforts to
cause the Board to nominate, and the shareholders of Employer to elect, Employee
as a director of Employer ("Director") at each successive annual meeting of
shareholders of Employer for so long as Employee serves as CEO. Employer hereby
also agrees to use its best efforts to cause the Board to name Employee to the
Executive Committee of the Board for so long as Employee serves as a Director
and CEO.

         2.       Term; Termination of Employment.

                  (a)      Employee's employment under this Agreement shall
commence as of May_____, 2003, and shall continue until December 31, 2008, and
for successive one-year periods thereafter (the "Employment Term"), unless
either Employee or Employer gives at least one-year's prior written notice of
intent not to renew the Employment Term, or Employee's employment is terminated
earlier by Employee or Employer as hereinafter provided.

<PAGE>

Immediately upon termination of Employee's employment hereunder for any reason
(other than death), Employee hereby agrees to resign as a Director and as a
director, officer, employee and agent of each of Employer's subsidiaries.

                  (b)      Employee may terminate his employment under this
Agreement, at any time, by giving at least three (3) months' prior written
notice of such termination to Employer. In the event that Employee terminates
his employment under this Agreement, on or after January 1, 2004, prior to or
later than nine (9) months after a Change in Control (as defined below),
Employee shall be entitled to two (2) months' Base Salary (as defined below) at
the end of the [three (3) months'] notice period. In the event that Employee
terminates his employment under this Agreement within nine (9) months after a
Change in Control, Employee shall be entitled to Severance Payments in the
amount and under the circumstances set forth in subsection 2(f) below.

                  (c)      Employer may terminate Employee's employment under
this Agreement, at any time, for any reason or for no reason, immediately by
giving written notice to Employee. In the event that Employer terminates
Employee's employment under this Agreement for Cause (as defined below),
Employee shall be entitled to no Severance Payments. In the event that Employer
terminates Employee's employment under this Agreement without Cause, Employee
shall be entitled to Severance Payments in the amount and under the
circumstances set forth in subsection 2(f). For purposes of this Agreement,
"Cause" shall be deemed to exist if (1) Employee commits fraud, theft, larceny,
or any other crime (other than minor misdemeanors); (2) Employee fails or
refuses to obey lawful instructions of the Board or of any committee thereof or
commits any willful misconduct or disloyalty; (3) Employee is guilty of habitual
insobriety, habitual inattention to his duties, functions, or responsibilities,
or repeated negligence in the performance of his duties, functions, or
responsibilities; or (4) Employee otherwise commits a material breach of this
Agreement.

                  (d)      Employee's employment under this Agreement shall
terminate automatically upon the death or disability of Employee, or upon the
expiration of the Employment Term after Employee or Employer has given the
notice of non-renewal provided for in subsection 2(a). For purposes of this
subsection 2(d), Employee shall be deemed to be disabled when he is deemed
disabled under Employer's disability policy for executive officers as in effect
at that time. In the event that Employee's employment under this Agreement
terminates due to death, disability, or non-renewal of the Employment Term,
Employee shall be entitled to no additional Base Salary or Severance Payments.

                  (e)      Upon any termination of Employee's employment under
this Agreement, Employee, his personal representatives, or his estate, as the
case may be, shall be entitled to receive, in addition to any additional Base
Salary or Severance Payments provided for herein, the Base Salary, Benefits (as
defined below), and Bonuses (as defined below) paid or provided to or earned by
Employee hereunder in respect of Employee's service through the date of such
termination. For purposes of this subsection 2(e), no EBITDA Bonus (as defined
below) shall be deemed to be earned by Employee in respect of a given fiscal
year unless he remains actively employed under this Agreement through June 30 of
such year, and, in the event that Employee's employment hereunder terminates
between July 1 and December 31 of such year, he shall be deemed to have earned a
EBITDA Bonus in respect of such year to the extent and in proportion

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to the percentage by which EBITDA has improved through the fiscal quarter end
(i.e., June 30, September 30, or December 31) closest to the date of such
termination (whether such termination occurs before or after such fiscal quarter
end) (a "Proportional EBIDTA Bonus")

                  (f)      (1) In the event that Employer terminates Employee's
                           employment under this Agreement without Cause
pursuant to subsection 2(c), or Employee terminates his employment under this
Agreement within nine (9) months after a Change in Control pursuant to
subsection 2(b), Employee shall be entitled to receive the Base Salary,
Benefits, and Bonuses paid or provided to or earned by Employee hereunder in
respect of Employee's service through the date of such termination and, in
addition, shall be entitled to receive severance payments (the "Severance
Payments") in the amount and under the circumstances set forth in this
subsection 2(f). Except in the case of a Change in Control as provided in
paragraph 2(f)(3), the Severance Payments shall consist of a continuation of
Employee's annual Base Salary, Benefits, and Bonuses in effect on the date of
termination, paid and provided on the same periodic and other bases as provided
for in subsections 3(a) and (b) below, as if Employee's employment hereunder
were continuing. In the case of a Change in Control after which Employee elects
to receive his Severance Payments in a lump-sum as provided in paragraph
2(f)(3), the Severance Payments shall be paid in a lump-sum as provided therein,
calculated based upon Employer's out-of-pocket costs to provide the Base Salary,
Benefits, and Bonuses with no discounting for present value, no tax gross-up or
discount, and no effort to pay for or otherwise provide comparable Benefits to
Employee. For purposes of subsection 2(f), "Bonuses" shall mean the aggregate of
the EBITDA Bonus and Discretionary Bonus (as defined below) earned or awarded in
respect of the last full fiscal year during which Employee was employed under
this Agreement immediately preceding Employee's termination, shall be considered
to be the bonus continuation for the severance period at issue, and shall be
separate and apart from the payment of any EBITDA or Discretionary Bonus paid or
earned in respect of that last full fiscal year and from any Proportional EBITDA
Bonus to which Employee may be entitled for the year in which the termination
occurs.

                           (2)      In the event that Employer terminates
Employee's employment under this Agreement without Cause pursuant to subsection
2(c) prior to a Change in Control or after two (2) years after a Change in
Control, Employee shall be entitled to Severance Payments equal to his
then-current annual Base Salary, Benefits, and Bonuses for (i) one (1) year if
such termination shall occur prior to January 1, 2004 or on or after January 1,
2006, or (ii) eighteen (18) months if such termination shall occur on or after
January 1, 2004 but prior to January 1, 2006.

                           (3)      In the event that Employer terminates
Employee's employment under this Agreement without Cause pursuant to subsection
2(c) at any time within two (2) years after a Change in Control, or Employee
terminates his employment under this Agreement pursuant to subsection 2(b) at
any time within nine (9) months after a Change in Control, then, notwithstanding
anything to the contrary contained in this Agreement, Employee shall be entitled
to Severance Payments equal to his then-current annual Base Salary, Benefits,
and Bonuses for (i) the greater of the number of full and partial years
remaining between the date of termination of employment and the end of the two
(2) year period following the Change in Control or eighteen (18) months, if such
termination shall occur prior to January 1, 2004, or (ii) two (2) years if such
termination shall occur on or after January 1, 2004. In the case of Severance

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Payments related to a termination of employment after a Change in Control, or
Severance Payments related to a termination of employment before a Change in
Control which Severance Payments continue after a Change in Control, the
Severance Payments, or any remaining portion thereof, shall, at the election of
Employee, be payable in a lump sum, net of withholding for all applicable taxes
and other amounts which may be properly withheld, within thirty (30) calendar
days following such election. For purposes of this Agreement, a "Change in
Control" shall be deemed to occur if, but only if, (a) Inberdon Enterprises Ltd.
("Inberdon") and its affiliates and associates, on a collective basis, cease to
beneficially own, directly or indirectly, at least forty percent (40%) of the
then-outstanding common stock of Employer, or (b) the current shareholders of
Inberdon and their affiliates and associates, on a collective basis, cease to
beneficially own, directly or indirectly, at least fifty percent (50%) of the
then-outstanding common stock of Inberdon.

                           (4)      Employee acknowledges and agrees that the
Severance Payments provided for herein shall be in full and total satisfaction
and settlement of any and all claims, suits, demands, judgments, actions, and
causes of action, of whatever nature, which at the time of such termination
Employee then has or may have against Employer or any affiliate, subsidiary,
Director, officer, employee, agent, or shareholder of Employer or of any of its
subsidiaries, arising by virtue of any thing whatsoever, including without
limitation claims based upon this Agreement, claims based upon other agreements,
claims based upon quasi-contract, claims sounding in tort, employment
discrimination claims, claims under the Employee Retirement Income Security Act
of 1974, and claims under any other federal, state, or local statute,
regulation, or common law. Employee and Employer further agree that, except in
the case of a termination of Employee's employment under this Agreement after a
Change in Control pursuant to paragraph 2(f)(3), prior to payment by Employer of
any Severance Payment or Payments, Employee and Employer shall each execute and
deliver irrevocable mutual general releases of Employer and all affiliates,
subsidiaries, Directors, officers, employees, agents, and shareholders of
Employer and all of its subsidiaries, and of Employee and his heirs and
executors, and releasing Employer, Employee, and such persons from all such
claims, in form and content reasonably acceptable to Employer, Employee, and
their respective counsel.

         3.       Compensation.

                  (a)      In consideration of the services to be rendered by
Employee under this Agreement, Employer shall pay Employee a salary (the "Base
Salary") at an annual rate of at least U.S. $250,000 per annum. During the first
(1st) quarter of each calendar year, commencing with the first (1st) quarter
2004, the Board or the Compensation Committee of the Board shall review and may,
in its discretion, increase the Base Salary, effective retroactive to January 1
of that year, and shall determine the amount of any bonus that Employee is to be
awarded with respect to the previous year based on the percentage increase in
EBITDA (the "EBITDA Bonus"). In addition to the EBITDA Bonus, Employee shall be
awarded such additional bonuses, from time to time, as the Board or the
Compensation Committee of the Board may in its discretion determine (a
"Discretionary Bonus"). The Base Salary shall be payable on a periodic basis, in
arrears, in accordance with Employer's customary payroll practices for its
executives from time to time, net of withholding for all applicable taxes and
other amounts which may be properly withheld. Employee's EBITDA Bonus, if any,
shall be paid within fifteen (15) calendar days after Employer publicly
announces its year-end results for the previous fiscal year in respect

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of which the EBITDA Bonus is to be calculated and paid. Discretionary Bonuses,
if any, shall be determined and paid as the Board or the Compensation Committee
of the Board may in its discretion determine.

                  (b)      During the course of his employment under this
Agreement, Employee shall be entitled to participate in all employee health
insurance, life insurance, sick leave, long-term disability, relocation (up to a
maximum of U.S. $80,000 for actual relocation costs), and other fringe benefit
programs of Employer, to the extent and on the same terms and conditions
(subject, however, to the terms and conditions of any such programs) as from
time to time are accorded other employees serving as executive officers of
Employer (the "Benefits"). As a part of Employee's Benefits, Employee shall also
be entitled to (1) an annual contribution of U.S. $30,000, to be paid by
Employer on January 1 of each year commencing January 1, 2004, to fund a life
insurance/retirement arrangement for Employee, and (2) to have Employer pay for
a single country club/social club membership in the Dallas, Texas area (up to a
maximum of U.S. $40,000, or such greater amount as may be mutually agreed upon
between Employee and the Executive Committee of the Board) and the annual club
membership dues for such club, during Employee's employment under this
Agreement.

                  (c)      Employee shall also be entitled to at least four (4)
weeks' paid vacation each calendar year, at times to be mutually agreed upon
between Employee and the Executive Committee of the Board.

                  (d)      Employer hereby agrees to use its best efforts to
cause the Compensation Committee of the Board to grant to Employee (1) 30,000
stock options, effective upon the date hereof, at the fair market value of a
share of Employer's common stock on the date of grant, and (2) 30,000 stock
options, effective on the last business day of Employer's fiscal year 2004 and
of each fiscal year thereafter during Employee's employment under this
Agreement, at the fair market value of a share of Employer's common stock on
such date.

                  (e)      Employer shall reimburse Employee for expenses
reasonably paid or incurred by Employee in connection with the performance of
his duties, functions, and responsibilities under this Agreement, provided that
Employee shall document all such expenses in accordance with Employer's
procedures in effect from time to time, including but not limited to the
following reasonable expenses incurred by Employee in performing his duties,
responsibility, and functions for Employer under this Agreement in Dallas,
Texas: travel to and from his home in Virginia, to Dallas, and lodging and other
expenses in the Dallas area, all subject to mutual agreement between Employee
and the Executive Committee of the Board. In addition, Employer shall provide to
Employee in Texas the use of a late model motor vehicle suitable to Employee's
executive position and shall pay the reasonable costs of maintaining and
operating such vehicle pursuant to the customary practices of Employer. Such
vehicle shall promptly be returned to Employer, in the same condition as
provided to Employee, reasonable wear and tear excepted, upon the termination of
Employee's employment for any reason.

                  (f)      In respect of Employee's employment under this
Agreement, Employer shall maintain directors' and officers' liability insurance
having coverage limits at least as high as presently being maintained by
Employer if the same shall be reasonably available in the judgment of the Board.

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<PAGE>

         4.       Confidential Information. Employee hereby agrees that he shall
not, during his employment under this Agreement or at any time thereafter,
furnish, disclose, or reveal to any third party, firm, or person (except in the
course of, and only to the extent required for, the proper performance of his
duties, functions, and responsibilities hereunder), nor use or appropriate to
his own personal use or benefit or permit any third party, firm, or other person
to use or benefit from, any information of any kind or character related in any
manner to Employer or its affiliates or subsidiaries, including without
limitation information with respect to it or their financial condition,
products, businesses, operations, plans, employees, customers, suppliers,
vendors, or prospective employees, customers, suppliers, or vendors, whether or
not acquired, learned, obtained, or developed by Employee alone or in
conjunction with others ("Confidential Information"). Upon the termination of
his employment under this Agreement for any reason, Employee shall promptly
return to Employer all papers, documents, films, blueprints, drawings, magnetic
tapes, diskettes, and other storage media (of any kind) in his possession either
containing or reflecting Confidential Information, or otherwise relating to
Employer or any of its affiliates or subsidiaries, and shall not retain copies
thereof.

         5.       Covenant Not To Compete; No Raid or Solicitation.

                  (a)      Employee agrees that, without the prior written
consent of Employer, he shall not, during his employment under this Agreement,
and for one (1) year following Employee's termination of his employment pursuant
to subsection 2(b) other than within nine (9) months after a Change in Control,
for six (6) months following the expiration of the Employment Term as a result
of Employee's notice of non-renewal given pursuant to subsection 2(a), for six
(6) months following Employer's termination of Employee's employment pursuant to
subsection 2(c) for Cause, for three (3) months following Employee's termination
of his employment pursuant to subsection 2(b) within nine (9) months after a
Change in Control, and for three (3) months following Employer's termination of
Employee's employment pursuant to subsection 2(c) without Cause (collectively,
the "Noncompetition Period"), engage or participate, directly or indirectly,
whether as an owner, partner, limited partner, member, director, officer,
employee, agent, consultant, or representative, in any business or other
enterprise competing, directly or indirectly, with Employer or any of its
affiliates or subsidiaries, whether now existing or hereafter created or
acquired (all the foregoing being collectively referred to herein as the
"Companies"), within the Noncompetition Areas (as defined below). A business or
other enterprise shall be deemed to be "competing" with the Companies if, within
any Noncompetition Area, it conducts (1) any line of business which the
Companies, or any of them, then conducts or has conducted within such
Noncompetition Area at any time within the one (1) year preceding the date of
termination of Employee's employment; and (2) any line of business which the
Companies, or any of them, plans, as of the date of termination of Employee's
employment, to enter within such Noncompetition Area within the one-year period
following the termination of Employee's employment. For purposes of this
Agreement, the term "Noncompetition Areas" shall mean all those geographic areas
where the Companies, or any of them, is doing business or competing for business
at the date of termination of Employee's employment for any reason. For purposes
of this subsection 5(a), a business enterprise shall be deemed to be conducting
"business" within the Noncompetition Areas if it maintains manufacturing,
production, quarrying, sales, or distribution facilities within the
Noncompetition Areas, or solicits or services customers located within such
Noncompetition Areas. Notwithstanding anything to the contrary contained in this
subsection 5(a), the described restrictions on Employee's activities shall not
be

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deemed to include Employee's direct or indirect beneficial ownership of any
equity securities in a publicly-traded business or other entity, which
securities do not constitute more than two percent (2%) of the relevant class of
equity security issued and outstanding, or give Employee "control" (as such term
is used in the Securities Act of 1933 and the rules and regulations promulgated
thereunder) of such entity.

                  (b)      During the Noncompetitive Period, Employee shall also
not, either alone or with or on behalf of any third party, firm, or other
person, solicit, induce, or influence any third party, firm, or other person to:
(1) solicit, divert, take away, or induce customers (wherever located) of any of
the Companies to avail themselves of the services or products of others which
are competitive with those of any of the Companies, or sell or furnish or seek
to sell or furnish such services or products to such customers; or (2) solicit,
divert, take away, or induce any employee of any of the Companies to leave the
employ of the Companies, or hire or employ or seek to hire or employ any person
who, at any time within six (6) months preceding such action, was an employee of
any of the Companies. For purposes of this subsection 5(b), the term "customers"
shall include any and all individuals, business organizations and entities, and
governmental agencies, no matter how organized and regardless of whether they
are organized for profit or not, with which any of the Companies has or had
agreements, contracts, or arrangements, to which any of the Companies has sold
any product or provided any service, or with which any of the Companies has
conducted business negotiations, in each such case at any time within three (3)
years prior to the termination of Employee's employment under this Agreement.

                  (c)      In the event that any court of competent jurisdiction
shall determine that any restriction on Employee contained in this Section 5 is
illegal, invalid, or unenforceable by reason of the nature, scope, temporal
period, or geographic area of such restriction, or for any other reason, the
parties agree that such restriction shall be modified and reformed to the
minimum extent necessary so that such restriction, as so modified and reformed,
shall be legal, valid, and enforceable in such jurisdiction. In such event, such
restriction as so modified and reformed shall continue in effect in such
jurisdiction and such restriction, as existing prior to such modification and
reformation, shall continue in full force and effect in all other jurisdictions.
It is the intention of the parties that all restrictions on Employee contained
herein shall be enforceable for the benefit of Employer to the maximum possible
extent.

         6.       Enforcement.

                  (a)      Employee recognizes and agrees that, in the event of
a breach of any of the provisions of Section 4 or 5 by Employee, Employer may
suffer irreparable harm and not have an adequate remedy at law. Accordingly,
Employee hereby agrees that, in the event of a breach or threatened breach by
Employee of any of the provisions contained in such Sections, Employer shall be
entitled, in addition to all other remedies which may be available to Employer,
to equitable relief, including without limitation enforcement of such provision
by temporary restraining order, preliminary and permanent injunction, and decree
of specific performance.

                  (b)      Except as set forth in subsection 6(a), any
controversy or claim arising out of or relating to this Agreement, or any breach
thereof, shall be settled by binding arbitration in the city in which Employer's
principal executive offices are located in accordance with the

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<PAGE>

Commercial Arbitration Rules of the American Arbitration Association, and
judgment upon the award rendered by the arbitrator(s) may be entered in any
court having jurisdiction thereof. The parties hereby agree to be bound by the
decision of the arbitrator(s).

         7.       Governing Law. This Agreement and the employment relationship
between Employer and Employee hereunder shall be governed by and construed and
enforced in accordance with the laws of the State of Texas, without regard to
the conflicts of law rules thereof.

         8.       Severability. If any provision of this Agreement is held to be
illegal, invalid, or unenforceable (and, with respect to provisions contained in
Section 5, cannot be modified and reformed pursuant to subsection 5(c) such that
such provision is thereafter legal, valid, and enforceable), such provision
shall be severed and stricken from this Agreement, and in all other respects
this Agreement shall remain in full force and effect.

         9.       Only Agreement; Amendments. This Agreement constitutes the
only agreement between Employer and Employee concerning the within subject
matter, and supersedes any and all prior oral or written communications between
Employer and Employee regarding the within subject matter. No amendment,
modification, or supplement to this Agreement shall be effective, unless it is
in writing and signed by Employer and Employee.

         10.      Agreement Binding; Successors and Assigns. This Agreement has
been duly authorized on behalf of Employer by the Board. This Agreement is
personal in nature, and no party hereto shall assign or transfer this Agreement
or any of its or his respective rights or obligations hereunder without the
prior written consent of the other party hereto. This Agreement shall inure to
the benefit of and be binding upon Employer and Employee and their respective
heirs, successors, and permitted assigns.

         11.      Notices. Any notice required or permitted to be given
hereunder shall be in writing and shall be delivered in person, by certified or
registered mail, return receipt requested, or by overnight courier, at the
address set forth opposite the intended recipient's name below. Either party may
by notice to the other party hereto change the address of the party to whom
notice is to be given. The date of notice shall be the date delivered, if
delivered in person, or the date received, if delivered by mail or overnight
courier.

         12.      Waiver. No waiver by any party to this Agreement of any
violation, breach, or default shall be effective unless the same shall be in
writing and signed. No waiver by any party of any violation, breach, or default
shall be construed to constitute a waiver of or consent to the present or future
violation, breach, or default of the same or of any other provision hereof.

         13.      No Reliance; Review by Attorney. Employee hereby acknowledges
and represents that he has had full opportunity to review financial statements
and other documents relating to Employer and to ask questions of Employer
concerning its condition, financial and otherwise, business, and prospects, but
has relied solely upon his independent analysis of Employer in deciding to
execute this Agreement, having received no representations or warranties from
Employer concerning its condition, financial or otherwise, business, or
prospects. In addition, Employee acknowledges and represents that he has had
full opportunity

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to review the terms and conditions of this Agreement with an attorney, that he
is executing this Agreement with full knowledge of the legal effect thereof
after advice of counsel, and that his execution of this Agreement and the
performance of his duties, functions, and responsibilities hereunder will not
conflict with, violate, breach, or constitute a default under any law,
ordinance, or regulation or any agreement, arrangement, or understanding to
which he is bound.

         IN WITNESS WHEREOF, Employer and Employee have executed this Agreement
as of the date first set forth above.

                                          UNITED STATES LIME &

                                          MINERALS, INC.

                                          By: __________________________________
                                              Edward A Odishaw, Esquire
                                              Chairman of the Board of Directors

Witness:                                  EMPLOYEE

__________________________________        ______________________________________

Employee's Address:                       Timothy W. Byrne
Timothy W. Byrne
c/o United States Lime & Minerals, Inc.
13800 Montfort Drive
Suite 330
Dallas, TX 75240

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