Document:

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                                                                    EXHIBIT 10.1

                  [ENVIRONMENTAL SAFEGUARDS, INC. LETTERHEAD]

                                August 17, 2000

Facsimile: 410-895-3805
Cahill, Warnock Strategic Partners Fund LP          Facsimile: 504-833-9506
Strategic Associates LP                             Newpark Resources, Inc.
One South Street, Ste 2150                          3850 N. Causeway, Ste 1770
Baltimore, Maryland 21202                           Metairie, LA 77002-1756
Attn: David L. Warnock                              Attn: Matt Hardy

James H. Stone
Stone Energy
909 Poydras Street, Ste 2650
New Orleans, LA 70112

RE: LOAN SECURITY AGREEMENT DATED DECEMBER 17, 1997 BETWEEN ENVIRONMENTAL
SAFEGUARDS, INC., NATIONAL FUEL & ENERGY, INC., ONSITE TECHNOLOGY L.L.C., JAMES
H. STONE, NEWPARK RESOURCES, INC., WARNOCK STRATEGIC PARTNERS FUND L.P.,
STRATEGIC ASSOCIATES, L.P. ("LOAN AGREEMENT") AND SERIES B CONVERTIBLE PREFERRED
AND SERIES C CONVERTIBLE PREFERRED STOCK PURCHASE AGREEMENT BETWEEN
ENVIRONMENTAL SAFEGUARDS, INC., JAMES H. STONE, NEWPARK RESOURCES, INC., WARNOCK
STRATEGIC PARTNERS FUND L.P., AND STRATEGIC ASSOCIATES, L.P. (STOCK AGREEMENT")

Dear Sirs:

Capitalized terms in this letter agreement shall have the same meaning as set
forth in the Loan Agreement. This letter agreement is to memorialize the
agreement in principle that has been reached between the parties to the Loan
Agreement and the Stock Agreement. The parties have agreed to the following with
regard to the Loan Agreement, the Stock Agreement the Notes and the Loan
Documents:

1.      Payment of principal and interest due and payable on September 4, 2000
        shall be deferred until March 4, 2001 and shall bear interest at the
        rate set forth in 2.2(a) of the Loan Agreement and not at the Default
        Rate.

2.      Payment of the Series C Preferred Stock Dividend due and payable on
        October 1, 2000 shall be deferred until April 1, 2001. Such deferred
        dividend shall bear interest at the rate set forth in 2.2(a) of the Loan
        Agreement and not at the Default Rate.

3.      Payment of principal only due and payable on December 4, 2000 shall be
        deferred until June 4, 2001 and shall bear interest at the rate set
        forth in 2.2(a) of the Loan Agreement and not at

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     the Default Rate.

4.   No late fees shall accrue with regard to any of the deferred amounts set
     forth in items 1 through 3 above.

5.   In consideration of the deferral of payments set forth in 1 through 3
     above, the Series C Preferred Shares shall be made convertible into common
     shares of Environmental Safeguards, Inc. From now through December 31, 2002
     the Series C Preferred shares shall be convertible into 1,777,777 shares of
     common stock of Environmental Safeguards at a conversion price of $2.25 per
     common share. Beginning on January 1, 2003 the Series C Preferred Shares
     shall be convertible into 4,000,000 shares of common stock of Environmental
     Safeguards at a conversion price of $1.00 per common share. Should
     Environmental Safeguards, at any time, default on any provisions of the
     Loan Agreement, the Series C Preferred Shares shall be convertible into
     shares of common stock of Environmental Safeguards and become immediately
     exercisable at a conversion price of the lesser of $1.00 per share or the
     average trailing 30 day stock price at the time of default. (Such
     conversion rights may be effected by either amendment of the Certificate of
     Designation of Series C Convertible Preferred Stock or exchange of the
     Series C Preferred Shares for newly created Series D Preferred Shares
     having conversion rights as stated herein). The Company shall take steps
     necessary to file a Certificate of Designation covering the new conversion
     provisions prior to September 4, 2000.

6.   The parties hereto agree to execute and deliver prior to September 4, 2000
     all documents necessary to effect the agreements set forth in this letter,
     including, but not limited to, amendments to the Loan Agreement, amendments
     to the Stock Agreement, amendments to the Notes, amendments to the
     Certificate of Designation of Series C Convertible Preferred Stock,
     amendments to the Loan Documents.

7.   EACH PARTY AGREES THAT TIME IS OF THE ESSENCE WITH REGARD TO THE MATTERS
     SET FORTH HEREIN. EACH PARTY FURTHER ADMITS AND AGREES THAT THE AGREEMENTS
     AND UNDERTAKINGS HEREIN SHALL BE ENFORCEABLE BY AN ACTION FOR SPECIFIC
     PERFORMANCE.

If this sets forth your understanding of the agreements reached by the parties,
please indicate by signing in the space provided below.

Very Truly Yours
Environmental Safeguards, Inc.
National Fuel & Energy, Inc.
OnSite Technology LLC

/s/ JAMES S. PERCELL
James S. Percell
President
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CAHILL, WARNOCK STRATEGIC PARTNERS FUND L.P.
BY: CAHILL, WARNOCK STRATEGIC PARTNERS L.P.

/s/ DAVID L. WARNOCK
--------------------------------------------
David L. Warnock
A General Partner
Date:

STRATEGIC ASSOCIATES L.P.
BY: CAHILL, WARNOCK & COMPANY LLC

/s/ DAVID L. WARNOCK
--------------------------------------------
David L. Warnock
Managing Member
Date:

NEWPARK RESOURCES, INC.

/s/ MATTHEW W. HARDY
--------------------------------------------
Matthew W. Hardy
V. P. Finance & CFO
8-18-2000

JAMES M. STONE

/s/ JAMES M. STONE
--------------------------------------------
Date:<PAGE>   1
                                                                    EXHIBIT 10.8

                              CONVEYANCE AGREEMENT

         This Conveyance Agreement is dated as of this 3rd day of April, 2000,
by and between Cal Dive International, Inc. ("Cal Dive"), a Minnesota
corporation, and OKCD Investments, Ltd., a Texas limited partnership, the
general partner of which is OKCD Holdings, Inc. (the "Partnership").

         WHEREAS, Cal Dive has entered into a Participation Agreement (the
"Agreement") executed on March 24, 2000, and effective as of February 1, 2000,
between it, Kerr-McGee Oil & Gas Corporation, a Delaware corporation
("Kerr-McGee") and certain others whereby Cal Dive has the right to participate
in an exploratory prospect and related wells and development thereafter; and

         WHEREAS, the Partnership has agreed to fund and bear the risk of the
exploration costs under the Agreement.

         NOW, THEREFORE, the parties, for the agreements contained herein, for
due and adequate consideration agree as follows:

         1. The Partnership agrees hereby to fund up to a total of $15 Million
in connection with the exploratory and appraisal activities of Cal Dive under
the Agreement. Upon execution of this Agreement the Partnership shall fund $4.5
Million cash pursuant to the express terms and conditions of the Agreement, as
all of Cal Dive's required capital contribution pursuant to the Agreement to
drill the first exploratory well. Cal Dive will not participate on a non-consent
basis unless and until the full amount committed by the Partnership hereby has
been called by Kerr-McGee under the Agreement and paid by the Partnership. Cal
Dive agrees to spend up to a total of $1.0 Million, in addition to the funding
of the Partnership for liabilities of Cal Dive under the Agreement for cost
overruns, under investment liability or abandonment liability accruing as a
result of non-consent participation in exploration and appraisal (all as defined
in the Agreement). Cal Dive further agrees to fund development costs up to $49
Million under the Agreement, Prior to non-consent or withdrawal of Cal Dive from
the Agreement.

         2. Cal Dive hereby agrees to convey to the Partnership the overriding
royalty of five percent (5%) of the 8/8ths as set forth on Exhibit A hereto,
upon the date of receipt of the working interest pursuant to the terms of the
Agreement, which is twenty percent (20%) of the 8/8ths.

         3. In the event that Cal Dive shall transfer any portion of its working
interest prior to commitment to the Initial Production System funding, then any
value received as a result of the transfer shall be conveyed to the Partnership.
The Partnership's overriding royalty interest in the Cal Dive working interest
shall be reduced on a pro-rata basis with the percentage of working interest
transferred.

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         4. Cal Dive and the Partnership agree to be bound by the express terms
and conditions of the Agreement and the Partnership hereby agrees that Cal Dive,
at all times, may make decisions pursuant to the Agreement that prefer Cal Dive
over the Partnership pursuant to the express terms and conditions of the
Agreement, and that Cal Dive may make all investment decisions thereunder
without regard to the benefit or cost to the Partnership.

         5. The parties hereto agree that Cal Dive shall have exclusive
authority and control over terms and conditions of the Agreement, the terms and
conditions of Cal Dive's participation in and decisions under the Agreement, the
working interest and that the sole purpose of this Agreement is to permit the
Partnership to fund the exploratory risk of Cal Dive under the Agreement.

         6. Cal Dive and the Partnership agree that the sole representation of
the Partner is OKCD Holdings, Inc., a Texas corporation, and sole general
partner of the Partnership.

         EXECUTED as of this date above written.

                                  CAL DIVE INTERNATIONAL, INC.
                                  a Minnesota corporation

                                  By:
                                      ------------------------------------------
                                  Printed Name:
                                                --------------------------------
                                  Title:
                                         ---------------------------------------

                                  OKCD INVESTMENTS, LTD.
                                  a Texas limited partnership

                                  By:      OKCD Holdings, Inc.
                                           General Partner

                                  By:
                                      ------------------------------------------
                                           Owen Kratz, President

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