Exhibit 99.1

                                 AMENDMENT NO. 4
                                       TO
                                CREDIT AGREEMENT

         This AMENDMENT NO. 4 TO CREDIT AGREEMENT (this "Amendment"), made as of
October 23, 2002, among OGLEBAY NORTON COMPANY ("Borrower"), the banking
institutions named in Schedule 1 to the Credit Agreement (as hereinafter
defined) (collectively, the "Banks" and individually, "Bank"), KEYBANK NATIONAL
ASSOCIATION, as administrative agent for the Banks ("Agent"), BANK ONE, MICHIGAN
(now known as Bank One, NA), as syndication agent ("Syndication Agent") and THE
BANK OF NOVA SCOTIA, as documentation agent ("Documentation Agent").

                                   WITNESSETH:

         WHEREAS, Borrower, the Banks, Agent, the Syndication Agent and the
Documentation Agent have entered into that certain Credit Agreement, dated as of
May 15, 1998, as amended and restated as of April 3, 2000, and as subsequently
amended by that certain Amendment No. 1 to Credit Agreement and Waiver, dated as
of June 30, 2001, Amendment No. 2 to Credit Agreement and Waiver, dated as of
November 9, 2001 and Amendment No. 3 to Credit Agreement and Waiver, dated as of
December 24, 2001 (as so amended from time to time, the "Credit Agreement"),
pursuant to which the Banks have made certain loans and other financial
accommodations available to Borrower; and

         WHEREAS, Borrower and the Banks desire to amend the Credit Agreement
further as hereinafter set forth;

         NOW, THEREFORE, in consideration of the mutual promises and agreements
contained herein and other good and valuable consideration, the receipt and
adequacy of which are hereby acknowledged, Borrower and the Banks hereby agree
as follows:

1.      DEFINED TERMS.

         Each defined term used herein and not otherwise defined herein shall
have the meaning ascribed to such term in the Credit Agreement.

2.      SCHEDULES 1, 2 AND 3 TO CREDIT AGREEMENT; UPDATED DISCLOSURE SCHEDULES.

         Schedules 1, 2 and 3 to the Credit Agreement are amended by deleting
the existing Schedules 1, 2 and 3 and replacing such schedules with Schedule 1,
Schedule 2 and Schedule 3 as attached hereto and such revised Schedules 1, 2 and
3 shall be incorporated into the Credit Agreement as if fully written therein.
In addition, the following Schedules to the Credit Agreement, Schedules 6.1,
6.4, 6.5, 6.17 and 6.19, are amended by deleting the existing Schedules 6.1,
6.4, 6.5, 6.17 and 6.19, and replacing such schedules with new Schedules 6.1,
6.4, 6.5, 6.17 and 6.19, attached hereto as Annex I, and such revised Schedules
6.1, 6.4, 6.5, 6.17 and 6.19 shall be incorporated into the Credit Agreement as
if fully written therein.



3.      AMENDMENT TO THE CREDIT AGREEMENT.

         3.1      Amendment to Article I. Article I, Definitions, is amended by:
(i) adding thereto new definitions "Amendment No. 4 Closing Date," "Noteholder
Intercreditor Agreement," "Material Recovery Event," "Net Cash Proceeds," "Note
Purchase Agreement," "Restated Revolving Credit Notes," "Revolving Credit
Notes," and "2002 Senior Secured Fund Notes" to be inserted into Article I in
appropriate alphabetical order and (ii) amending the definitions of "Applicable
Commitment Fee Rate," "Applicable Margin," "Change in Control" and "Commitment
Period," to read as follows:

         "Amendment No. 4 Closing Date" shall mean date on which the "Amendment
Effective Date" (as such term is defined in Section 5 hereof) occurs.

         "Applicable Commitment Fee Rate" shall mean:

                  (a)    for the period commencing on the Amendment No. 4
         Closing Date until but excluding the first day of the month after the
         date of receipt by Agent of the financial statements for the fiscal
         quarter ending December 31, 2002, sixty two and one-half (62.50) basis
         points; and

                  (b)    commencing on the first day of the month after the date
         of receipt by Agent of the financial statements for the fiscal quarter
         ending December 31, 2002, the number of basis points set forth in the
         following matrix, based upon the result of the computation of the
         Leverage Ratio, shall be used to establish the number of basis points
         that will go into effect on such date and thereafter:



   -------------------------------------------------------------------------------------------------------
                                                                                   Applicable
                              Leverage Ratio                                  Commitment Fee Rate
   -------------------------------------------------------------------------------------------------------
                                                                         
    Greater than 6.50 to 1.00                                               65.00 basis points
   -------------------------------------------------------------------------------------------------------
    Greater than or equal to 6.00 to 1.00 but less than or equal to         62.50 basis points
    6.50 to 1.00
   -------------------------------------------------------------------------------------------------------
    Greater than or equal to 5.50 to 1.00 but less than 6.00 to 1.00             62.50 basis points
   -------------------------------------------------------------------------------------------------------
    Greater than or equal to 5.00 to 1.00 but less than 5.50 to 1.00             62.50 basis points
   -------------------------------------------------------------------------------------------------------
    Greater than or equal to 4.50 to 1.00 but less than 5.00 to 1.00             50.00 basis points
   -------------------------------------------------------------------------------------------------------
    Greater than or equal to 4.00 to 1.00 but less than 4.50 to 1.00             50.00 basis points
   -------------------------------------------------------------------------------------------------------
    Greater than or equal to 3.50 to 1.00 but less than 4.00 to 1.00             50.00 basis points
   -------------------------------------------------------------------------------------------------------
    Less than 3.50 to 1.00                                                       50.00 basis points
   -------------------------------------------------------------------------------------------------------


Changes to the Applicable Commitment Fee Rate shall be effective on the first
day of the month following the date upon which Agent received, or, if earlier,
Agent should have received, pursuant to Section 5.3 (a) or (b) hereof, the
quarterly or annual financial statements of the Companies and the Compliance
Certificate with respect thereto. The above matrix does not modify or waive, in
any respect, the requirements of Section 5.7 hereof, the rights of the Banks to
charge the Default Rate in lieu of the rate specified in the matrix above, or
the rights and remedies of the Banks pursuant to Articles VII and VIII hereof.

                                        2



         "Applicable Margin" shall mean:

                  (a)    for the period commencing on the Amendment No. 4
         Closing Date until but excluding the first day of the month after the
         date of receipt by Agent of the financial statements for the fiscal
         quarter ending December 31, 2002, (i) four hundred twenty five (425)
         basis points for LIBOR Loans, and (ii) two hundred (200) basis points
         for Prime Rate Loans, and

                  (b)    commencing on the first day of the month after the date
         of receipt by Agent of the financial statements for the fiscal quarter
         ending December 31, 2002, the number of basis points (depending upon
         whether Loans are LIBOR Loans or Prime Rate Loans) set forth in the
         following matrix, based upon the result of the computation of the
         Leverage Ratio, shall be used to establish the number of basis points
         that will go into effect on such date and thereafter; provided, however
         that, in the event Borrower does not permanently reduce the aggregate
         amount of the Term Loan Commitment under the Term Loan Agreement and
         the Revolving Credit Commitment under the Credit Agreement by a minimum
         of $75,000,000 (exclusive of the $60,000,000 permanent reduction of the
         Revolving Credit Commitments of the Banks hereunder effective as of the
         Amendment No. 4 Closing Date) within one (1) year after the Amendment
         No. 4 Closing Date, the number of basis points established with respect
         to each level of the matrix for the Applicable Margin for LIBOR Loans
         (and Letters of Credit Fees) and the Applicable Margin for Prime Rate
         Loans will in each case be increased by fifty (50) basis points (with
         such increased pricing remaining effective until such reduction does
         take place at which time the pricing indicated on the matrix shall
         again be controlling); provided, further, however, that the increase
         otherwise required pursuant to this proviso shall not be required if:
         (i) Borrower has proposed one or more asset sales or capital market
         transactions the aggregate proceeds of which would have resulted in the
         required permanent reduction in the Revolving Credit Commitment, (ii)
         the Agent has determined, in the exercise of its good faith discretion
         (which determination the Agent hereby agrees to complete in a
         reasonably prompt time schedule), that such proposed asset sale or
         sales or capital market transactions are financially reasonable from a
         credit perspective and (iii) notwithstanding such determination, the
         Banks have not consented to such sales or transactions:



- ------------------------------------------------------------------------------------------------------------------
                                                     Applicable Margin                  Applicable Margin
                   Leverage Ratio                     for LIBOR Loans                 for Prime Rate Loans
- ------------------------------------------------------------------------------------------------------------------
                                                                                
 Greater than 6.50 to 1.00                                 450 basis points              225 basis points
- ------------------------------------------------------------------------------------------------------------------
 Greater than or equal to 6.00 to 1.00 but less than       425 basis points              200 basis points
 or equal to 6.50 to 1.00
- ------------------------------------------------------------------------------------------------------------------
 Greater than or equal to 5.50 to 1.00 but less than       400 basis points              175 basis points
 6.00 to 1.00
- ------------------------------------------------------------------------------------------------------------------
 Greater than or equal to 5.00 to 1.00 but less than       375 basis points              150 basis points
 5.50 to 1.00
- ------------------------------------------------------------------------------------------------------------------


                                        3




                                                                                   
- ------------------------------------------------------------------------------------------------------------------
 Greater than or equal to 4.50 to 1.00 but less than       350 basis points              125 basis points
 5.00 to 1.00
- ------------------------------------------------------------------------------------------------------------------
 Greater than or equal to 4.00 to 1.00 but less than       325 basis points              100 basis points
 4.50 to 1.00
- ------------------------------------------------------------------------------------------------------------------
 Greater than or equal to 3.50 to 1.00 but less than       300 basis points               75 basis points
 4.00 to 1.00
- ------------------------------------------------------------------------------------------------------------------
 Less than 3.50 to 1.00                                    275 basis points               50 basis points
- ------------------------------------------------------------------------------------------------------------------


Changes to the Applicable Margin shall be effective on the first day of the
month following the date upon which Agent received, or, if earlier, Agent should
have received, pursuant to Section 5.3 (a) or (b) hereof, the quarterly or
annual financial statements of the Companies and the Compliance Certificate with
respect thereto. The above matrix does not modify or waive, in any respect, the
requirements of Section 5.7 hereof, the rights of the Banks to charge the
Default Rate in lieu of the rate specified in the matrix above, or the rights
and remedies of Agent and the Banks pursuant to Articles VII and VIII hereof.

         "Change of Control" shall mean the occurrence of any one of any the
following events: (a) the acquisition of, or, if earlier, the shareholder or
director approval of the acquisition of, ownership or voting control, directly
or indirectly, beneficially or of record, on or after the Closing Date, by any
Person or group (as the terms beneficial ownership, person, and group are used
for purposes of or are within the meaning of Rule 13d-3 of the SEC under the
Securities Exchange Act of 1934, as then in effect), shares representing more
than fifty-percent (50%) of the aggregate Voting Power (whether exclusive or
non-exclusive) represented by the issued and outstanding capital stock of
Borrower; (b) the occupation of a majority of the seats (other than vacant
seats) on the board of directors of Borrower by Persons who were neither (i)
nominated by the board of directors of Borrower nor (ii) appointed by directors
so nominated; (c) the Board of Directors or stockholders of Borrower shall
approve (i) any consolidation or merger of Borrower where the stockholders of
Borrower, immediately prior to the consolidation or merger, would not,
immediately after the consolidation or merger, beneficially own, directly or
indirectly, shares representing in the aggregate 50% or more of the voting
shares of the corporation issuing cash or securities in the consolidation or
merger (or of its ultimate parent corporation, if any), (ii) any asset sale of
all or substantially all of the assets of Borrower or any division thereof, and
(iii) any plan or proposal for the liquidation or dissolution of Borrower; or
(d) the 2002 Senior Secured Fund Notes (or any of them) or any other
Indebtedness under the 2002 Senior Secured Fund Notes shall cease to constitute,
or Borrower and its Subsidiaries (or any of them) shall challenge in writing or
otherwise that, the 2002 Senior Secured Fund Notes (or any of them) or any other
Indebtedness under the 2002 Senior Secured Fund Notes constitute "Senior
Indebtedness" and "Designated Senior Indebtedness" in each case as such term is
defined in the Indenture.

         "Commitment Period" shall mean the period from the Amendment No. 4
Closing Date to the earlier of: (i) October 31, 2004, (ii) the date on which the
Commitment shall have been terminated pursuant to Article VIII hereof or (iii)
so long as the Noteholder Intercreditor Agreement remains in effect, the date on
which there has been full, final and indefeasible repayment of all Debt
hereunder and under the Loan Agreement (as referenced in section 2.10 of

                                        4



the Noteholder Intercreditor Agreement).

         "Noteholder Intercreditor Agreement" shall mean that certain
Intercreditor Agreement, dated as of October 25, 2002, between the holders of
the 2002 Senior Secured Fund Notes, The 1818 Mezzanine Fund II, L.P., in its
capacity as secured collateral agent for such holders, and the Agent on behalf
of itself and the Banks.

         "Material Recovery Event" shall mean (a) any casualty loss in respect
of assets of Borrower or any of its Subsidiaries covered by casualty insurance,
(b) any compulsory transfer or taking under threat of compulsory transfer of any
asset of Borrower or any of its Subsidiaries with a fair market value in excess
of One Hundred Thousand Dollars ($100,000) by any agency, department, authority,
commission, board, instrumentality or political subdivision of the United
States, any state or municipal government, and (c) any recovery in good funds by
Borrower or any of its Subsidiaries by reason of a non-appealable judgment
against any other Person in excess of One Hundred Thousand Dollars ($100,000) to
the full extent thereof.

         "Net Proceeds" shall mean

         (a) the cash proceeds (including cash proceeds subsequently received in
respect of non-cash consideration initially received) from any sale, transfer or
other disposition of assets of Borrower or any of its Subsidiaries to a Person
(other than: (i) any sale of inventory in the ordinary course, (ii) disposition
in the ordinary course of Borrower's or any of its Subsidiaries' business of
assets that are obsolete, worn out or no longer used or useful in Borrower's or
any of its Subsidiaries business, (iii) any sale of accounts or contract claims
in each case reasonably deemed by Borrower to be of questionable collectability,
(iv) disposition of capital assets the proceeds of which (net of taxes payable
with respect to the disposition and the reasonable costs and expenses of sale)
are reinvested within a reasonable period of time and in the ordinary course of
business in capital assets of Borrower or its Subsidiaries, or (v) any sale,
transfer or other disposition of assets of Borrower or any of its Subsidiaries
to Borrower or any other Subsidiary of Borrower) to the extent that such sale
proceeds (in each case, net of (x) selling expenses, including without
limitation any reasonable broker's fees or commissions, costs of discontinuing
operations associated with such assets and sales, transfer and similar taxes and
(y) the repayment of any Indebtedness secured by a purchase money Lien on such
assets that is permitted under this Agreement) exceeds Two Hundred and Fifty
Thousand Dollars ($250,000) in any fiscal year of Borrower and its consolidated
Subsidiaries and only to the extent of such excess;

         (b) the cash proceeds from the issuance and/or sale of equity or debt
securities of Borrower or any Subsidiaries thereof pursuant to any public
offering, Rule 144A offering, or private placement with one or more
institutional investors, net of transaction costs (including customary fees,
costs and expenses including, without limitation, underwriters' or placement
agents' discounts and commissions and transfer and similar taxes) (excluding any
(i) proceeds from the issuance or sale of equity or debt securities in
connection with a Permitted Acquisition and (ii) proceeds from the issuance of
any equity or debt securities pursuant to compensation plans for employees,
executive officers or directors of Borrower and the Subsidiaries thereof, and

         (c) the cash proceeds from any Material Recovery Event (net of any
amounts in respect of insurance proceeds or proceeds of compulsory takings which
are reinvested in repair or replacement of the capital assets of Borrower or the
Subsidiaries thereof which were subject to such casualty or taking within a
reasonable period of time and in the ordinary course of

                                        5



business).

         "Note Purchase Agreement" shall mean that certain Senior Secured Note
Purchase Agreement, dated as of October 25, 2002, among Borrower, the guarantors
listed therein, The 1818 Mezzanine Fund II, L.P. and the other Purchasers which
are signatories thereto (as therein defined).

         "Restated Revolving Credit Note" shall mean each Restated Revolving
Credit Note executed and delivered in connection with that certain Amendment No.
4 to Credit Agreement, dated as of October 23, 2002.

         "Revolving Credit Note" shall mean any Restated Revolving Credit Note
executed and delivered in connection with that certain Amendment No. 4 to Credit
Agreement, dated as of October 23, 2002.

         "2002 Senior Secured Fund Notes" shall mean those certain Senior Notes
of Borrower in the original principal amount of $75,000,000 with a coupon of 18%
per annum, of which 13% per annum is payable in cash and 5% per annum is
payable, at the option of Borrower, in cash or in-kind and having a final
maturity date of October 25, 2008 issued by Borrower pursuant to the Note
Purchase Agreement.

         3.2      Amendment to Section 2.5.  The introductory clause of Section
2.5(c) is amended to read as follows:

         SECTION 2.5 COMMITMENT AND OTHER FEES; REDUCTION OF COMMITMENTS.

                  . . .

                         (c)   In addition to any mandatory reduction of
                  Commitments required by this Agreement, . . .


         3.3      Amendment to Section 2.7 Section 2.7 of the Credit Agreement
shall be amended in its entirety to read as follows:

                  SECTION 2.7.     MANDATORY PREPAYMENT; MANDATORY REDUCTION OF
         COMMITMENT.

                         (a)   MANDATORY PAYMENT. If the Revolving Credit
                  Exposure at any time exceeds the Total Commitment Amount,
                  Borrower shall, as promptly as practicable, but in no event
                  later than the next Business Day, prepay an aggregate
                  principal amount of the Revolving Loans sufficient to bring
                  the aggregate outstanding principal amount of all such Loans
                  and the aggregate undrawn face amount of all issued and
                  outstanding Letters of Credit within the Commitment. Any
                  prepayment of a LIBOR Loan pursuant to this Section 2.7(a)
                  shall be subject to the prepayment breakage fees set forth in
                  Section 2.4 hereof.

                         (b)   MANDATORY APPLICATION OF NET PROCEEDS; RESULTING
                  MANDATORY REDUCTION IN REVOLVING CREDIT COMMITMENTS AND TERM
                  LOANS.

                                       6



                               (I)     APPLICATION OF NET PROCEEDS. From and
                         after the Amendment No. 4 Closing Date, Borrower shall
                         apply all Net Proceeds relating to Borrower promptly
                         upon receipt thereof to prepay Term Loans under the
                         Loan Agreement and Revolving Loans hereunder
                         outstanding at the time of such receipt with such
                         prepayments being applied pro rata among the Banks;
                         provided, however, that Borrower shall have the option
                         of specifying the portion of the proceeds to be applied
                         to outstanding Term Loans under the Loan Agreement, in
                         the inverse order of maturity and to outstanding
                         Revolving Loans; provided, further, however, that
                         nothing in this Subsection or in the definition of "Net
                         Proceeds" shall (i) constitute authorization not
                         otherwise permitted by this Agreement for Borrower or
                         any Subsidiary thereof to enter into any transaction
                         that would generate Net Proceeds and (ii) affect the
                         application of proceeds of the 2002 Senior Secured Fund
                         Notes to prepayment of the Revolving Loans and the
                         reduction immediately thereafter to the Revolving
                         Credit Commitments of the Banks as required by
                         Amendment No. 4 to Credit Agreement.

                               (II)    POSTPONEMENT OF PREPAYMENT; EFFECT OF
                         PREPAYMENT AS COMMITMENT REDUCTION. Unless an Event of
                         Default has occurred which is continuing and has not
                         been waived in accordance with Section 10.3 hereof, in
                         the event that the making of any prepayment of
                         Revolving Credit Loans or Term Loans required by this
                         Section would result in an obligation on the part of
                         Borrower to make a breakage payment in respect thereof
                         under Section 2.4 of this Agreement (unless waived in
                         accordance with Section 10.3 hereof), Borrower may upon
                         notice to Agent postpone making such prepayment for a
                         period of up to 30 days or such shorter period as will
                         result in no such breakage payment being payable. Each
                         prepayment with respect to Term Loans and Revolving
                         Credit Loans required by this Section 2.7 shall
                         constitute not only a prepayment but also a permanent
                         reduction in the amount of the applicable Term Loan
                         Commitment under the Loan Agreement and Revolving
                         Credit Commitment of the Banks hereunder. Amounts
                         prepaid with respect to Term Loans may not be
                         reborrowed.

         3.4      Amendment to Section 5.7 Section 5.7 of the Agreement shall be
modified by amending Subsections (a), (b), (c), (d), (e), (f) and (g) thereof to
read as follows:

         SECTION 5.7 FINANCIAL COVENANTS

                  (a)    LEVERAGE RATIO. The Companies shall not suffer or
         permit at any time the Leverage Ratio to exceed: (i) 6.75 to 1.00 on
         July 1, 2002 through September 30, 2002, (ii) 6.35 to 1.00 on October
         1, 2002 through December 31, 2002, (iii) 6.50 to 1.00 on January 1,
         2003 through March 31, 2003, (iv) 6.55 to 1.00 on April 1, 2003 through
         June 30, 2003, (v) 6.25 to 1.00 on July 1, 2003 through September 30,
         2003, (vi) 5.90 to 1.00 on October 1, 2003 through December 31, 2003,
         (vii) 6.20 to 1.00 on January 1, 2004 through March 31, 2004, (viii)
         6.15 to 1.00 on April 1, 2004 through June 30, 2004, and (ix) 5.85 to
         1.00 on July 1, 2004 and thereafter.

                                        7



                  (b)    SENIOR SECURED DEBT RATIO. The Companies shall not
         suffer or permit at any time the ratio of: (x) Total Senior Funded
         Indebtedness to the extent such Indebtedness is a secured obligation
         (but, excluding for purposes hereof, the Indebtedness evidenced by the
         2002 Senior Secured Fund Notes) to (y) Consolidated Pro-Forma EBITDA to
         be greater than: (i) 4.60 to 1.00 on July 1, 2002 through September 30,
         2002, (ii) 3.55 to 1.00 on October 1, 2002 through December 31, 2002,
         (iii) 3.75 to 1.00 on January 1, 2003 through March 31, 2003, (iv) 3.80
         to 1.00 on April 1, 2003 through June 30, 2003, (v) 3.55 to 1.00 on
         July 1, 2003 through September 30, 2003, (vi) 3.25 to 1.00 on October
         1, 2003 through December 31, 2003, (vii) 3.55 to 1.00 on January 1,
         2004 through June 30, 2004, and (viii) 3.25 to 1.00 on July 1, 2004 and
         thereafter, in each case, based upon the financial statements of the
         Companies for the most recently completed four (4) fiscal quarters.

                  (c)    INTEREST COVERAGE. The Companies shall not suffer or
         permit at any time the ratio of: (x) Consolidated Pro-Forma EBITDA to
         (y) Consolidated Pro-Forma Interest Expense (less non cash amortized
         financing and FAS 133 costs to the extent included in Consolidated
         Pro-Forma Interest Expense in accordance with GAAP) to be less than:
         (i) 1.49 to 1.00 on July 1, 2002 through December 31, 2002, (ii) 1.47
         to 1.00 on January 1, 2003 through March 31, 2003, (iii) 1.45 to 1.00
         on April 1, 2003 through June 30, 2003, (iv) 1.48 to 1.00 on July 1,
         2003 through September 30, 2003, (v) 1.53 to 1.00 on October 1, 2003
         through December 31, 2003, (vi) 1.55 to 1.00 on January 1, 2004 through
         March 31, 2004, (vii) 1.60 to 1.00 on April 1, 2004 through June 30,
         2004, and (viii) 1.64 to 1.00 on July 1, 2004 and thereafter, in each
         case, based upon the financial statements of the Companies for the most
         recently completed four (4) fiscal quarters.

                  (d)    CASH-FLOW COVERAGE. The Companies shall not suffer or
         permit at any time the ratio of: (x) Consolidated Pro-Forma Cash Flow
         to (y) Consolidated Pro-Forma Fixed Charges (excluding from Pro-Forma
         Fixed Charges for purposes of calculating compliance with this
         covenant, amounts payable with respect to the Revolving Loans and the
         Term Loans (as defined in the Loan Agreement) to be less than: (i) 0.92
         to 1.00 on July 1, 2002 through September 30, 2002, (ii) 1.00 to 1.00
         on October 1, 2002 through December 31, 2002, (iii) 0.95 to 1.00 on
         January 1, 2003 through March 31, 2003, (iv) 0.94 to 1.00 on April 1,
         2003 through June 30, 2003, (v) 0.98 to 1.00 on July 1, 2003 through
         September 30, 2003, (vi) 1.00 to 1.00 on October 1, 2003 through
         December 31, 2003, (vii) 1.03 to 1.00 on January 1, 2004 through March
         31, 2004, (viii) 1.08 to 1.00 on April 1, 2004 through June 30, 2004,
         and (ix) 1.14 to 1.00 on July 1, 2004 and thereafter, in each case,
         based upon the financial statements of the Companies for the most
         recently completed four (4) fiscal quarters.

                  (e)    NET WORTH. The Companies shall not suffer or permit
         Consolidated Net Worth at any time, based upon the Consolidated
         financial statements of the Companies for the most recently completed
         fiscal quarter, to fall below the current minimum amount required,
         which current minimum amount required shall be: (i) as of June 30, 2002
         the amount required pursuant to this clause (e) as in effect prior to
         the Amendment No. 4 to Credit Agreement, (ii) as of September 30, 2002,
         an amount equal to $108, 513,000, (iii) as of December 31, 2002, an
         amount equal to $104,768,000, (iv) as of March 31, 2003, an amount
         equal to $98,643,000, (v) as of June 30, 2003, an amount

                                        8



         equal to $101,512,000, (vi) as of September 30, 2003, an amount equal
         to $104,524,000, (vii) as of December 31, 2003 an amount equal to
         $102,120,000, (viii) as of March 31, 2004, an amount equal to
         $96,395,000, (ix) as of June 30, 2004, an amount equal to $99,664,000
         and (x) as of September 30, 2004 and thereafter, an amount equal to
         $103,250,000; provided, however, in each case, that (i) any non-cash
         impact to Consolidated Net Worth related to FAS 142 shall be excluded
         in calculating Borrower's compliance with this covenant and (ii) any
         potential non-cash impact associated with the extinguishment of
         Indebtedness (as a result of the issuance of the 2002 Senior Secured
         Fund Notes and the required repayment of a portion of the Revolving
         Credit Loans) as indicated pursuant to EITF 96.19/SFAS 140 shall
         likewise be excluded in calculating Borrower's compliance with this
         covenant.

                  (f)    MINIMUM CONSOLIDATED PRO-FORMA EBITDA. The Companies
         shall not suffer or permit at any time Consolidated Pro-Forma EBITDA to
         be less than (i) $61,000,000 from the Amendment No. 4 Closing Date
         through September 30, 2002, (ii) $63,500,000 on October 1, 2002 through
         December 31, 2002, (iii) $65,000,000 on January 1, 2003 through March
         31, 2003, (iv) $66,000,000 on April 1, 2003 through June 30, 2003, (v)
         $67,500,000 on July 1, 2003 through September 30, 2003, and (vi) $68,
         000,000 on October 1, 2003 and thereafter, in each case, based upon the
         financial statements of the Companies for the most recently completed
         four (4) fiscal quarters.

                  (g)    MINIMUM REVOLVING CREDIT AVAILABILITY. The Companies
         shall at all times maintain a Revolving Credit Availability of not less
         than $7,500,000 from the Amendment No. 4 Closing Date and at all times
         thereafter.

         3.5      Amendment to Section 5.1. Section 5.1 is amended by deleting
in its entirety the proviso to the third sentence thereof.

         3.6      Amendment to Section 5.8. Section 5.8 is amended by (i)
deleting the word "or" at the end of subsection (g), (ii) deleting the period at
the end of subsection (h) and adding a semicolon followed by the word "or" and
(iii) adding the following subsection (i) at the end thereof to read as follows:

         . . .

         (i)      the Indebtedness incurred under the 2002 Senior Secured Fund
         Notes and, without effecting the limitation set forth in section 7.5(y)
         hereof, the Note Purchase Agreement.

         3.7      Amendment to Section 5.9. Section 5.9 is amended by (i)
deleting the word "or" at the end of subsection (h), (ii) deleting the period at
the end of subsection (i) and adding a semicolon followed by the word "or" and
(iii) adding the following subsection (j) at the end thereof to read as follows:

         . . .

         (i)      the Liens securing the 2002 Senior Secured Fund Notes but only
         to the extent such Liens are subordinated by agreement, in form and
         substance satisfactory to the Agent on behalf of the Banks, providing
         that such Liens can not be enforced against any collateral and such
         collateral can not be realized upon pursuant to such Liens until prior
         full, final and indefeasible payment of the Debt.

         3.8      Amendment to Section 5.13. Section 5.13 is amended to read as
follows:

                                        9



                  SECTION 5.13.  ACQUISITIONS. Without the prior written consent
         of Agent and the Majority Banks, no Company shall effect an Acquisition
         or Permitted Acquisition; provided the Banks hereby consent to the
         Acquisition of Erie Sand and Gravel so long as the Companies are in
         compliance with the Loan Documents both before and after such
         Acquisition and provided the total consideration paid does not exceed
         the amount specified in section 6.15 of the Note Purchase Agreement as
         originally executed.

         3.9      Amendment to Section 5.17. Section 5.17 is amended by adding
the following proviso at the end thereof to read as follows:

         . . .; provided, however, that no portion of the proceeds of the Loans
         or Letters of Credit shall be used to refund or repay or otherwise
         retire or redeem any portion of the Indebtedness with respect to the
         Indenture or the 2002 Senior Secured Fund Notes; provided, further,
         however that Borrower may use any portion of the proceeds to make
         scheduled interest payments with respect to such Indebtedness and to
         make the redemption payment required upon Borrower's failure to
         consummate the Acquisition of Erie Sand and Gravel as such requirement
         is specified in the Note Purchase Agreement as originally executed.

         3.10     Amendment to Section 5.18. Section 5.18 is amended to read as
follows:

                  SECTION 5.18.  CAPITAL EXPENDITURES. Borrower and its
         Subsidiaries shall not invest in Consolidated Capital Expenditures in
         an aggregate amount exceeding $27,500,000 in any fiscal year.

         3.11     Amendment to Section 5.21. Section 5.21 is amended to read as
follows:

                  SECTION 5.21.  RESTRICTED PAYMENTS. No Company shall (a) make
         any payment including, but not limited to, any prepayment, mandatory
         redemption or optional redemption of any kind, or (b) exercise any
         right of defeasance or covenant defeasance or similar right, with
         respect to any Subordinated Indebtedness or the 2002 Senior Secured
         Funds Notes, except that: (i) Borrower may (x) make regularly scheduled
         payments of interest with respect to the 2002 Senior Secured Fund
         Notes, (y) elect to make cash payments in lieu of additions to
         principal with respect to "PIK Interest" under and as defined in the
         Note Purchase Agreement and (z) make the redemption payment with
         respect to the 2002 Senior Secured Fund Notes permitted by the final
         proviso to Section 5.17 hereof and (ii) if no Event of Default shall
         then exist or immediately thereafter shall begin to exist, Borrower
         may: (x) make regularly scheduled payments of interest with respect to
         any Subordinated Indebtedness.

         3.12     Addition of Section 5.31  Article V is amended by adding
Section 5.31 thereto to read as follows:

                  SECTION 5.31.  APPRAISAL EXECUTIVE SUMMARY. Prior to the
         Amendment No. 4 Closing Date, Borrower shall have furnished to Agent,
         in scope mutually acceptable to Agent and Borrower, and in form and
         substance acceptable to Agent, executive summary reports of appraisals
         by an independent third party appraiser recognized in the industry of
         Companies' material mineral rights.

         3.13     Addition of Section 5.32  Article V is amended by adding
Section 5.32 thereto to read as follows:

                                       10



                  SECTION 5.32.  OTHER COVENANTS. In the event that Borrower
         shall enter into, or shall have entered into, any material Indebtedness
         (including the Indebtedness evidenced by the 2002 Senior Secured Fund
         Notes), wherein the covenants (excluding covenants relating to the
         preservation of personal property) are more restrictive than the
         covenants set forth herein, Borrower shall be bound hereunder by such
         covenants with the same force and effect as if such covenants and
         agreements were written herein and fully incorporated herein.

         3.14     Amendment to Section 7.2. Section 7.2 is amended in its
entirety to read as follows:

                  SECTION 7.2.   SPECIAL COVENANTS. If any Company or any
         Obligor shall fail or omit to perform and observe Sections 5.1, 5.2,
         5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 5.11, 5.12, 5.13, 5.14, 5.15, 5.16,
         5.17, 5.18, 5.19, 5.20, or 5.21 hereof.

         3.15 Amendment to Section 7.3. Section 7.3 is amended to replace the
words "thirty (30) days" with the words "fifteen (15) days" therein.

         3.16     Amendment to Section 7.5. Section 7.5 is amended in its
entirety to read as follows:

                  SECTION 7.5.   CROSS DEFAULT. If any Company or any Obligor
         (x) shall default in the payment of principal or interest due and owing
         upon any (A) obligation for borrowed money or in respect of any
         Indebtedness, other than Indebtedness incurred in the ordinary course
         of business and owed to trade creditors, in excess of One Hundred
         Thousand Dollars ($100,000) or (B) Indebtedness incurred in the
         ordinary course of business and owed to trade creditors in excess of
         Three Million Dollars ($3,000,000) beyond any period of grace provided
         with respect thereto or in the performance or observance of any other
         agreement, term or condition contained in any agreement under which
         such obligation is created, if the effect of such default is to allow
         the acceleration of the maturity of such Indebtedness or to permit the
         holder thereof to cause such Indebtedness to become due prior to its
         stated maturity or (y) suffer any event or condition which would allow
         the holder or holders of such obligations to require the mandatory
         repurchase or redemption of all or a portion of such Indebtedness
         (other than scheduled redemptions and other than the redemption
         required by section 6.15 of the Note Purchase Agreement as originally
         executed).

         3.17     Amendment to Section 7.6. Section 7.6 is amended to replace
the words "Two Million Five Hundred Thousand Dollars ($2,500,000)" with the
words "One Million Dollars ($1,000,000)" therein.

         3.18     Amendment to Section 7.8. Section 7.8 is amended to replace
the words "One Million Five Hundred Thousand Dollars ($1,500,000)" with the
words "Five Hundred Thousand Dollars ($500,000)" therein.

         3.19     Amendment to Section 7.12. Clause (d) of Section 7.12 is
amended to read as follows:

         . . . (d) any Company incurs (as defined in the Indenture) any
         Designated Senior Indebtedness (as defined in the Indenture) other than
         the Debt or the Debt (as defined in the Loan Agreement) or the
         Indebtedness evidenced by the 2002 Senior Secured Fund Notes; . . .

                                       11



         3.20     Amendment to Section 7.14. Article VII is amended by adding
Section 7.14 and 7.15 thereto to read as follows:

                  SECTION 7.14.  NOTE PURCHASE AGREEMENT. If (a) any Event of
         Default (as defined in the Note Purchase Agreement), or any event or
         condition that with the lapse of time or the giving of notice or both
         would constitute an Event of Default (as defined in the Note Purchase
         Agreement), shall exist under the Note Purchase Agreement or any
         agreement executed in connection therewith; (b) without the prior
         written consent of the Majority Banks, the financial covenants set
         forth in Article VIII of the Note Purchase Agreement shall be amended,
         restated or modified to be more restrictive than those set forth in the
         Note Purchase Agreement as originally executed or the Note Purchase
         Agreement is amended, restated or modified to add additional financial
         covenants not set forth in the Note Purchase Agreement as originally
         executed; provided, however, the limitation set forth in this clause
         (b) shall not prohibit the creation of a more restrictive covenant to
         the extent the creation of such more restrictive covenant does not
         decrease the proportional differential existing between such financial
         covenant in the Note Purchase Agreement as originally executed to the
         corresponding financial covenant in this Agreement as amended by
         Amendment No. 4 to Credit Agreement; (c) the Indebtedness incurred in
         connection with the Note Purchase Agreement shall be accelerated for
         any reason; (d) Borrower shall exercise any rights of prepayment,
         optional redemption or similar right under the Note Purchase Agreement
         other than the redemption payment with respect to the 2002 Senior
         Secured Fund Notes permitted by the final proviso to Section 5.17
         hereof.

                  SECTION 7.15   NOTEHOLDER INTERCREDITOR AGREEMENT. The
         Noteholder Intercreditor Agreement is attempted to be revoked by any
         holder of the 2002 Junior Secured Fund Notes or any collateral agent
         thereof or is otherwise asserted to be invalid or unenforceable by the
         Company or any holder of the 2002 Junior Secured Fund Notes or any
         collateral agent thereof, or any such party asserts the invalidity or
         unenforceability of the Debt in connection with its rights under the
         Noteholder Intercreditor Agreement.

         3.21     Amendment to Section 10.3. Section 10.3 is amended to add the
following sentence at the end thereof to read as follows:

         No amendment, modification, action, notice or waiver of any provision
         of the Noteholder Intercreditor Agreement shall be taken by the Agent
         without the written consent of the Majority Banks.

4.      REPRESENTATIONS AND WARRANTIES.

         Borrower hereby represents and warrants as follows:

         4.1      The Amendment. This Amendment has been duly and validly
executed by an authorized executive officer of Borrower and constitutes the
legal, valid and binding obligation of Borrower enforceable against Borrower in
accordance with its terms. The execution, delivery, and performance of this
Amendment, the Credit Agreement (as amended hereby), and the other Loan
Documents to which Borrower is a party are within Borrower's corporate powers,
have been duly authorized, and are not in contravention of Law or the terms of
Borrower's Certificate of Incorporation or By-Laws or any indenture (including
the Indenture) or other document or

                                       12



instrument evidencing borrowed money or any other agreement or undertaking to
which Borrower is a party or by which it or its property is bound.

         4.2      Claims and Defenses. As of the date of this Amendment, neither
Borrower nor any of the Companies has any defenses, claims, counterclaims or
setoffs with respect to the Credit Agreement, the Loan Documents or any
obligations thereunder or with respect to any actions of Agent, the Syndication
Agent, the Documentation Agent, the Banks or any of their respective officers,
directors, shareholders, employees, agents or attorneys, and Borrower
irrevocably and absolutely waives any such defenses, claims, counterclaims and
setoffs and releases Agent, the Syndication Agent, the Documentation Agent, the
Banks, and each of their respective officers, directors, shareholders,
employees, agents and attorneys, from the same.

         4.3      Credit Agreement; Status of Credit Agreement. The Credit
Agreement, as amended by this Amendment, remains in full force and effect and
remains the valid and binding obligation of Borrower enforceable against
Borrower in accordance with its terms. As of the date of this Amendment, (i) the
representations and warranties of Borrower set forth in the Credit Agreement are
true and correct with the same force and effect as if made on and as of such
date except to the extent that any thereof expressly relate to an earlier date
and except that Borrower reserves the right to update the disclosures set forth
in Schedule 6.3 relating to permits such within 14 days after the date hereof
(such reservation being subject (a) to the condition that such updated
disclosure is in form and substance satisfactory to the Majority Banks and (b)
to Borrower's affirmation by execution hereof that the representations and
warranties of Borrower set forth in Section 6.3 are true and correct with the
same force and effect as if made on and as of such date) and (ii) no Unmatured
Event of Default or Event of Default shall then exist.

         4.4      Nonwaiver. The execution, delivery, performance and
effectiveness of this Amendment shall not, except to the extent provided in
Article 6 of this Amendment, operate, be deemed to be, or be construed to be a
waiver: (i) of any right, power or remedy of Agent, the Syndication Agent, the
Documentation Agent, any Bank under the Credit Agreement or (ii) of any term,
provision, representation, warranty or covenant contained in the Credit
Agreement or any other documentation executed in connection therewith. Further,
except to the extent provided in Article 6 of this Amendment, none of the
provisions of this Amendment shall constitute, be deemed to be or construed to
be: (i) a waiver of any Event of Default under the Credit Agreement as
previously amended and as further amended by this Amendment or (ii) a revocation
of any prior written waivers of any Events of Default thereunder.

         4.5      Reference to and Effect on the Credit Agreement. Upon the
effectiveness of this Amendment, each reference in the Credit Agreement to "this
Agreement," "hereunder," "hereof," "herein," or words of like import shall mean
and be a reference to the Credit Agreement, as previously amended and as further
amended hereby, and each reference to the Credit Agreement in any other
document, instrument or agreement executed and/or delivered in connection with
the Credit Agreement shall mean and be a reference to the Credit Agreement, as
previously amended and as further amended hereby.

5.      CONDITIONS PRECEDENT TO EFFECTIVENESS OF THIS AMENDMENT NO. 4.

         This Amendment shall become effective as of the time (the "Amendment
Effective Date") on which each of the following conditions precedent shall have
been fulfilled:

                                       13



         5.1      Amendment No. 4 to Credit Agreement. Agent shall have received
from Borrower and each of the Banks an original counterpart of this Amendment
No. 4 to Credit Agreement, executed and delivered by a duly authorized officer
of Borrower or such Bank, as the case may be.

         5.2      Amendment No. 4 to Loan Agreement. Agent shall have received
from Borrower and each of the Banks an original counterpart of Amendment No. 4
to Loan Agreement, in form and substance acceptable to Agent, executed and
delivered by a duly authorized officer of Borrower or such Bank, as the case may
be.

         5.3      Acknowledgment of Guarantors. Agent shall have received the
Acknowledgment of Guarantors, attached hereto, executed and delivered by a duly
authorized officer of each of the Guarantors.

         5.4      Amendment No. 1 to Security Agreements. Agent shall have
received from Borrower and each of the Banks an original counterpart of
Amendment No. 1 to Security Agreements, in form and substance acceptable to
Agent, executed and delivered by a duly authorized officer of Borrower or such
Bank, as the case may be.

         5.5      Issuance of 2002 Senior Secured Fund Notes; Permanent
Reduction of Revolving Credit Commitment. Borrower shall have: (i) successfully
issued its 2002 Senior Secured Fund Notes and received net proceeds
($75,000,000, net of selling expenses, including without limitation, any
reasonable broker's fees or commissions, and other costs directly related to
such sales) from such issuance (ii) used, immediately upon receipt by Borrower
of the funds, not less than $57,000,000 to repay, ratably among the Banks, the
Revolving Credit Loans and (iii) immediately thereafter shall permanently reduce
by $60,000,000 the Revolving Credit Commitment of the Banks; provided, however
that such repayment of the outstanding Revolving Loans shall not require
Borrower to pay any prepayment fee pursuant to Section 2.4 of Credit Agreement.
The Note Purchase Agreement and the other Junior Credit Documents shall have
been executed by the parties thereto.

         5.6      Noteholder Intercreditor Agreement. The Noteholder
Intercreditor Agreement, dated as of October 25, 2002, between the holders of
the 2002 Senior Secured Fund Notes, The 1818 Mezzanine Fund II, L.P., in its
capacity as secured collateral agent for such holders, Borrower and its
Subsidiaries which are Pledgors, and the Agent on behalf of itself and the
Banks, shall have been duly executed and delivered by and to all parties thereto
(the Agent being hereby authorized to execute the Noteholder Intercreditor
Agreement on behalf of the Banks as the secured party for the Banks under the
Loan Documents).

         5.7      Execution and Delivery of Restated Revolving Credit Notes.
Agent shall have received for delivery to the Banks, Restated Revolving Credit
Notes, duly executed by Borrower, evidencing the reduced Revolving Credit
Commitment of each of the Banks in the principal amount equal to the Revolving
Credit Commitment as so reduced.

         5.8      Amendment Fee; Agent Fees. Agent shall have received, for the
benefit of each Bank (including Agent in its capacity as a Bank) approving both
this Amendment and Amendment No. 4 to Loan Agreement, a one time amendment fee
in the amount of one hundred (100.00) basis points multiplied by the sum of the
Revolving Credit Commitment of such Bank (as set forth opposite such Bank's name
under the column headed "Revolving Credit

                                       14



Commitment Amount" in the revised Schedule 1 to the Credit Agreement attached
hereto) plus the Term Loan Commitment Amount (as defined in the Loan Agreement)
of such Bank.

         5.9      Opinion Concerning Amendment No. 4 to Credit Agreement and
Noteholder Intercreditor Agreement. Agent shall have received an opinion of
counsel to Borrower and its subsidiaries, in form and substance satisfactory to
the Agent, as to the authorization, due execution and delivery, and
enforceability by and against Borrower and the Subsidiaries thereof which are
parties thereto of this Amendment No. 4 to Credit Agreement, Amendment No. 4 to
Loan Agreement and the Noteholder Intercreditor Agreement.

         5.10     Opinion Concerning Indenture. Agent shall have received the
opinion issued by counsel to Borrower to the purchasers of the 2002 Senior
Secured Fund Notes as to the issuance of such notes in compliance with the
Indenture and a reliance letter from such counsel in favor of the Agent allowing
the Agent to rely on such opinion.

So long as each other conditions precedent is then satisfied, this Amendment
shall be deemed to be effective simultaneously with the satisfaction of the
conditions set forth in section 5.6 hereof.

6.      Waiver of Covenant Violation.

                  The Banks hereby waive Borrower's violation of Section 5.7(b)
[Senior Secured Debt Ratio] as of September 30, 2002 and agree not to enforce
their rights and remedies under the Credit Agreement with respect to the
resulting Events of Default; provided, however, that: (i) as of the effective
time of this waiver, in all other respects Borrower shall be in full compliance
with the Credit Agreement and (ii) the foregoing waiver shall not extend to or
prejudice any rights of the Agent and the Banks in respect of any other breach,
if any, by Borrower of any other provisions of the Credit Agreement. The
execution of this Amendment by Borrower shall serve as an acknowledgment (i)
that the foregoing waiver shall not affect the continued legality, validity and
binding effect of the Credit Agreement in its entirety and (ii) that the Credit
Agreement continues to be fully enforceable, in each case, except as otherwise
waived herein.

7.      MISCELLANEOUS.

         7.1      Governing Law. This Amendment has been delivered and accepted
at and shall be deemed to have been made at Cleveland, Ohio. This Amendment
shall be interpreted and the rights and liabilities of the parties hereto
determined in accordance with the laws of the State of Ohio, without regard to
principles of conflict of law, and all other laws of mandatory application.

         7.2      Severability. Each provision of this Amendment shall be
interpreted in such manner as to be valid under applicable law, but if any
provision hereof shall be invalid under applicable law, such provision shall be
ineffective to the extent of such invalidity, without invalidating the remainder
of such provision or the remaining provisions hereof.

         7.3      Counterparts. This Amendment may be executed in one or more
counterparts, each of which, when taken together, shall constitute but one and
the same agreement.

[Signature Page to Follow]

                                       15



         IN WITNESS WHEREOF, Borrower has caused this Amendment No. 4 to Credit
Agreement to be duly executed and delivered by its duly authorized officer as of
the date first above written.

Address:    1100 Superior Avenue           OGLEBAY NORTON COMPANY
            Cleveland, Ohio 44114
            Attention: Treasurer           By:  /s/ Julie A. Boland
                                              ----------------------------------
                                           Name:    Julie A. Boland
                                                --------------------------------
                                           Title:   Chief Financial Officer
                                                 -------------------------------



Address:    Key Center                     KEYBANK NATIONAL ASSOCIATION,
            127 Public Square              as a Bank and as Agent
            Cleveland, Ohio 44114-1306
            Attention: Large Corporate     By:  /s/ Thomas J. Purcell
            Banking Division                  ----------------------------------
                                           Name:    Thomas J. Purcell
                                                --------------------------------
                                           Title:   Sr. Vice President
                                                 -------------------------------


Address:    611 Woodward Avenue            BANK ONE, NA (formerly known as Bank
            Detroit, Michigan 48226        One, Michigan)
            Attention: Large Corporate
            Banking Division               By:  /s/ Glenn A. Currin
                                              ----------------------------------
                                           Name:    Glenn A. Currin
                                                --------------------------------
                                           Title:   Director
                                                 -------------------------------

Address:    600 Peachtree Street           THE BANK OF NOVA SCOTIA
            Suite 2700
            Atlanta, Georgia 30308         By:  /s/ N. Bell
                                              ----------------------------------
            Attention: Large Corporate     Name:    N. Bell
            Banking Division                    --------------------------------
                                           Title:   Assistant Agent
                                                  ------------------------------

                                       S-1



Address:    500 Woodward Avenue, 9th Fl.      COMERICA BANK
            Detroit, Michigan 48226
            Attention:  Large Corporate       By:      /s/ Jeffrey J. Judge
                                                 -------------------------------
            Banking Division                  Name:    Jeffrey J. Judge
                                                   -----------------------------
                                              Title:   Vice President
                                                    ----------------------------

Address:    231 S. LaSalle Street             BANK OF AMERICA, N.A.
            Chicago, Illinois 60697
            Attention:  Peter J. Gates        By:      /s/ Ronald Prince
                                                 -------------------------------
            Banking Division                  Name:    Ronald Prince
                                                   -----------------------------
                                              Title:   Sr. Vice President
                                                    ----------------------------

Address:    111 West Monroe, 10W              HARRIS TRUST AND SAVINGS BANK
            Chicago, Illinois  60603
            Attention:  Large Corporate       By:      /s/ Sarah U. Johnston
                                                 -------------------------------
            Banking Division                  Name:    Sarah U. Johnston
                                                   -----------------------------
                                              Title:   Vice President
                                                    ----------------------------

Address:    975 Euclid Avenue                 THE HUNTINGTON NATIONAL BANK
            Cleveland, Ohio  44115
            Attention:  Large Corporate       By:      /s/ John R. Macks
                                                 -------------------------------
            Banking Division                  Name:    John R. Macks
                                                   -----------------------------
                                              Title:   Vice President
                                                    ----------------------------

Address:    6 High Ridge Park                 GE CAPITAL CFE, INC.
            Building 6C, Mail Stop 4097-203
            Stamford Ct, 06927-5100           By:   /s/ William S. Richardson
                                                 -------------------------------
            Attention:  Commercial Finance    Name:    William S. Richardson
                                                   -----------------------------
                                              Title:   Duly Authorized Signatory
                                                    ----------------------------

Address:    1900 East Ninth Street            NATIONAL CITY BANK
            Cleveland, Ohio  44114
            Attention:  Large Corporate       By:     /s/ Janice E. Focke
                                                 -------------------------------
            Banking Division                  Name:    Janice E. Focke
                                                   -----------------------------
                                              Title:   Sr. Vice President
                                                    ----------------------------

Address:    250 West Huron                    JPMORGAN CHASE BANK
            Cleveland, Ohio  44113
            Attention:  Large Corporate       By:    /s/ Henry W. Centa
                                                 -------------------------------
            Banking Division                  Name:    Henry W. Centa
                                                   -----------------------------
                                              Title:   Vice President
                                                    ----------------------------

                                      S-2




                                    
Address:   1404 East Ninth Street         FIFTH THIRD BANK
           Cleveland, Ohio  44114
           Attention: Large Corporate     By:       /s/ Roy C. Lanctot
                                             ----------------------------------------
           Banking Division               Name:    Roy C. Lanctot
                                               --------------------------------------
                                          Title:   Vice President
                                                -------------------------------------



Address:   1350 Euclid Avenue             U. S. BANK, NATIONAL ASSOCIATION
           Cleveland, Ohio                (f\k\a Firstar Bank National Association)
           Attention: Commercial          By:     /s/ Christine C. Gencer
                                             ----------------------------------------
           Banking Division               Name:    Christine C. Gencer
                                               --------------------------------------
                                          Title:   Vice President
                                                -------------------------------------


Address:   1185 Avenue of the Americas    FLEET NATIONAL BANK
           New York, New York 10036
           Attention:  Manhattan          By:     /s/ Thomas G. Carley
                                             ----------------------------------------
           Commercial                     Name:    Thomas G. Carley
                                               --------------------------------------
                                          Title:   Vice President
                                                -------------------------------------


Address:   110 South Stratford Road       BRANCH BANKING & TRUST CO.
           Suite 301
           Winston-Salem, NC 27104        By:     /s/ James C. Stallings
                                             ----------------------------------------
           Attention: Large Corporate     Name:    James C. Stallings
                                               --------------------------------------
           Banking Division               Title:   Assistant Vice President
                                                -------------------------------------


                                       S-3



                          ACKNOWLEDGMENT OF GUARANTORS

         Each of the undersigned consents and agrees to and acknowledges the
terms of the foregoing Amendment No. 4 to Credit Agreement as of the date first
above written. Each of the undersigned further agrees that the obligations of
each of the undersigned pursuant to the Guaranty of Payment, the Security
Agreement and any other Loan Document to which any of the undersigned is a party
shall remain in full force and effect and be unaffected hereby.

                                ONCO Investment Company
                                Oglebay Norton Management Company
                                Oglebay Norton Industrial Sands, Inc.
                                Oglebay Norton Terminals, Inc.
                                Oglebay Norton Engineered Materials, Inc.
                                Michigan Limestone Operations, Inc.
                                Global Stone Corporation (successor by merger to
                                         Oglebay Norton Acquisition Company)
                                Global Stone Tenn Lutrell Company
                                Global Stone Chemstone Corporation
                                Global Stone St. Clair, Inc.
                                Global Stone Management Company
                                Global Stone Filler Products Company
                                Global Stone James River, Inc.
                                GS PC, Inc.
                                Oglebay Norton Minerals, Inc.
                                Oglebay Norton Specialty Minerals, Inc.
                                ON Coast Petroleum Company
                                ON Marine Services Company
                                ONCO WVA, Inc.
                                ONTEX, Inc.
                                Saginaw Mining Company

                                By:     /s/ Rochelle F. Walk
                                     ----------------------------------
                                         Rochelle F. Walk, as Vice President and
                                Secretary of each of the companies listed above.

                                Texas Mining, LP, by its General Partner
                                 ONTEX, Inc.

                                         By:      /s/ Rochelle F. Walk
                                              --------------------------------
                                                   Rochelle F. Walk
                                                   Vice President and Secretary

                                Global Stone PenRoc, LP, by
                                its General Partner, GS PC,
                                Inc,.

                                         By:      /s/ Rochelle F. Walk
                                              --------------------------------
                                                   Rochelle F. Walk,
                                                   Vice President and Secretary

                                Oglebay Norton Marine Services Company, L.L.C.,
                                by its Member ON Marine Services Company

                                         By:    /s/ Rochelle F. Walk
                                              ----------------------------
                                                  Rochelle F. Walk
                                                  Vice President and Secretary

                                       S-4



               Oglebay Norton Marine Management Company, LLC. by its member
               Oglebay Norton Marine Services Company, L.L.C.

                          By:     /s/ Rochelle F. Walk
                               ----------------------------
                                   Rochelle F. Walk
                                   Vice President and Secretary

               Global Stone Portage, LLC by its member Global Stone Corporation
               ---------------------------

                          By:     /s/ Rochelle F. Walk
                               ----------------------------
                                   Rochelle F. Walk
                                   Vice President and Secretary

                                       S-5