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(Local Currency-Single Jurisdiction)

                                   ISDA(R)
                 International Swap Dealers Association, Inc.


                               MASTER AGREEMENT
                           dated as of April 3, 1998


   CORESTATES BANK, N.A.          and    UNITED STATES LIME & MINERALS, INC.
--------------------------------       ---------------------------------------
have entered and/or anticipate entering into one or more transactions (each a 
"Transaction") that are or will be governed by this Master Agreement, which 
includes the schedule (the "Schedule"), and the documents and other confirming 
evidence (each a "Confirmation") exchanged between the parties confirming 
those Transactions.

Accordingly, the parties agree as follows: -

1.   Interpretation

(a)  Definitions. The terms defined in Section 12 and in the Schedule will 
have the meanings therein specified for the purpose of this Master Agreement.

(b)  Inconsistency. In the event of any inconsistency between the provisions 
of the Schedule and the other provisions of this Master Agreement, the 
Schedule will prevail.  In the event of any inconsistency between the 
provisions of any Confirmation and this Master Agreement (including the 
Schedule), such Confirmation will prevail for the purpose of the relevant 
Transaction.

(c)  Single Agreement. All Transactions are entered into in reliance on the 
fact that this Master Agreement and all Confirmations form a single agreement 
between the parties (collectively referred to as this "Agreement"), and the 
parties would not otherwise enter into any Transactions.

2.   Obligations

(a)  General Conditions.

     (i)  Each party will make each payment or delivery specified in each 
     Confirmation to be made by it, subject to the other provisions of this 
     Agreement.

     (ii)  Payments under this Agreement will be made on the due date for 
     value on that date in the place of the account specified in the 
     relevant Confirmation or otherwise pursuant to this Agreement, in 
     freely transferable funds and in the manner customary for payments in 
     the required currency.  Where settlement is by delivery (that is, other 
     than by payment), such delivery will be made for receipt on the due 
     date in the manner customary for the relevant obligation unless 
     otherwise specified in the relevant Confirmation or elsewhere in this 
     Agreement.


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     (iii)  Each obligation of each party under Section 2(a)(i) is subject 
     to (1) the condition precedent that no Event of Default or Potential 
     Event of Default with respect to the other party has occurred and is 
     continuing, (2) the condition precedent that no Early Termination Date 
     in respect of the relevant Transaction has occurred or been effectively 
     designated and (3) each other applicable condition precedent specified 
     in this Agreement.
     
(b)  Change of Account. Either party may change its account for receiving a 
payment or delivery by giving notice to the other party at least five Local 
Business Days prior to the scheduled date for the payment or delivery to which 
such change applies unless such other party gives timely notice of a 
reasonable objection to such change.

(c)  Netting. If on any date amounts would otherwise be payable: -

     (i)  in the same currency; and

     (ii) in respect of the same Transaction,

by each party to the other, then, on such date, each party's obligation to 
make payment of any such amount will be automatically satisfied and discharged 
and, if the aggregate amount that would otherwise have been payable by one 
party exceeds the aggregate amount that would otherwise have been payable by 
the other party, replaced by an obligation upon the party by whom the larger 
aggregate amount would have been payable to pay to the other party the excess 
of the larger aggregate amount over the smaller aggregate amount.

The parties may elect in respect of two or more Transactions that a net amount 
will be determined in respect of all amounts payable on the same date in the 
same currency in respect of such Transactions, regardless of whether such 
amounts are payable in respect of the same Transaction.  The election may be 
made in the Schedule or a Confirmation by specifying that subparagraph (ii) 
above will not apply to the Transactions identified as being subject to the 
election, together with the starting date (in which case subparagraph (ii) 
above will not, or will cease to, apply to such Transactions from such date).  
This election may be made separately for different groups of Transactions and 
will apply separately to each pairing of branches or offices through which the 
parties make and receive payments or deliveries.

(d)  Default Interest; Other Amounts. Prior to the occurrence or effective 
designation of an Early Termination Date in respect of the relevant 
Transaction, a party that defaults in the performance of any payment 
obligation will, to the extent permitted by law and subject to Section 6(c), 
be required to pay interest (before as well as after judgment) on the overdue 
amount to the other party on demand in the same currency as such overdue 
amount, for the period from (and including) the original due date for payment 
to (but excluding) the date of actual payment, at the Default Rate.  Such 
interest will be calculated on the basis of daily compounding and the actual 
number of days elapsed.  If, prior to the occurrence or effective designation 
of an Early Termination Date in respect of the relevant Transaction, a party 
defaults in the performance of any obligation required to be settled by 
delivery, it will compensate the other party on demand if and to the extent 
provided for in the relevant Confirmation or elsewhere in this Agreement.

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3.  Representations

Each party represents to the other party (which representations will be deemed 
to be repeated by each party on each date on which a Transaction is entered 
into) that: -

(a)  Basic Representations.

     (i)   Status. It is duly organized and validly existing under the laws 
     of the jurisdiction of its organization or incorporation and, if 
     relevant under such laws, in good standing;

     (ii)  Powers. It has the power to execute this Agreement and any other 
     documentation relating to this Agreement to which it is a party, to 
     deliver this Agreement and any other documentation relating to this 
     Agreement that it is required by this Agreement to deliver and to 
     perform its obligations under this Agreement and any obligations it has 
     under any Credit Support Document to which it is a party and has taken 
     all necessary action to authorize such execution, delivery and 
     performance;

     (iii) No Violation or Conflict. Such execution, delivery and 
     performance do not violate or conflict with any law applicable to it, 
     any provision of its constitutional documents, any order or judgment of 
     any court or other agency of government applicable to it or any of its 
     assets or any contractual restriction binding on or affecting it or any 
     of its assets;

     (iv)  Consents. All governmental and other consents that are required 
     to have been obtained by it with respect to this Agreement or any 
     Credit Support Document to which it is a party have been obtained and 
     are in full force and effect and all conditions of any such consents 
     have been complied with; and

     (v)   Obligations Binding. Its obligations under this Agreement and any 
     Credit Support Document to which it is a party constitute its legal, 
     valid and binding obligations, enforceable in accordance with their 
     respective terms (subject to applicable bankruptcy, reorganization, 
     insolvency, moratorium or similar laws affecting creditors' rights 
     generally and subject, as to enforceability, to equitable principles of 
     general application (regardless of whether enforcement is sought in a 
     proceeding in equity or at law)).

(b)  Absence of Certain Events. No Event of Default or Potential Event of 
Default or, to its knowledge, Termination Event with respect to it has 
occurred and is continuing and no such event or circumstance would occur as a 
result of its entering into or performing its obligations under this Agreement 
or any Credit Support Document to which it is a party.

(c)  Absence of Litigation. There is not pending or, to its knowledge, 
threatened against it or any of its Affiliates any action, suit or proceeding 
at law or in equity or before any court, tribunal, governmental body, agency 
or official or any arbitrator that is likely to affect the legality, validity 


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or enforceability against it of this Agreement or any Credit Support Document 
to which it is a party or its ability to perform its obligations under this 
Agreement or such Credit Support Document.

(d)  Accuracy of Specified Information. All applicable information that is 
furnished in writing by or on behalf of it to the other party and is 
identified for the purpose of this Section 3(d) in the Schedule is, as of the 
date of the information, true, accurate and complete in every material 
respect.

4.   Agreements

Each party agrees with the other that, so long as either party has or may have 
any obligation under this Agreement or under any Credit Support Document to 
which it is a party: -

(a)  Furnish Specified Information. It will deliver to the other party any 
forms, documents or certificates specified in the Schedule or any Confirmation 
by the date specified in the Schedule or such Confirmation or, if none is 
specified, as soon as reasonably practicable.

(b)  Maintain Authorizations. It will use all reasonable efforts to maintain 
in full force and effect all consents of any governmental or other authority 
that are required to be obtained by it with respect to this Agreement or any 
Credit Support Document to which it is a party and will use all reasonable 
efforts to obtain any that may become necessary in the future.

(c)  Comply with Laws. It will comply in all material respects with all 
applicable laws and orders to which it may be subject if failure so to comply 
would materially impair its ability to perform its obligations under this 
Agreement or any Credit Support Document to which it is a party.

5.   Events of Default and Termination Events

(a)  Events of Default. The occurrence at any time with respect to a party or, 
if applicable, any Credit Support Provider of such party or any Specified 
Entity of such party of any of the following events constitutes an event of 
default (an "Event of Default") with respect to such party: -

     (i)   Failure to Pay or Deliver. Failure by the party to make, when 
     due, any payment under this Agreement or delivery under Section 2(a)(i) 
     or 2(d) required to be made by it if such failure is not remedied on or 
     before the third Local Business Day after notice of such failure is 
     given to the party;

     (ii)  Breach of Agreement. Failure by the party to comply with or 
     perform any agreement or obligation (other than an obligation to make 
     any payment under this Agreement or delivery under Section 2(a)(i) or 
     2(d) or to give notice of a Termination Event) to be complied with or 
     performed by the party in accordance with this Agreement if such 
     failure is not remedied on or before the thirtieth day after notice of 
     such failure is given to the party;



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      (iii) Credit Support Default.

          (1)  Failure by the party or any Credit Support Provider of such 
          party to comply with or perform any agreement or obligation to be 
          complied with or performed by it in accordance with any Credit 
          Support Document if such failure is continuing after any applicable
          grace period has elapsed;

          (2)  the expiration or termination of such Credit Support Document
          or the failing or ceasing of such Credit Support Document to be in
          full force and effect for the purpose of this Agreement (in either
          case other than in accordance with its terms) prior to the
          satisfaction of all obligations of such party under each Transaction
          to which such Credit Support Document relates without the written
          consent of the other party; or

          (3)  the party or such Credit Support Provider disaffirms,
          disclaims, repudiates or rejects, in whole or in part, or challenges
          the validity of, such Credit Support Document;

     (iv)  Misrepresentation. A representation made or repeated or deemed to 
     have been made or repeated by the party or any Credit Support Provider 
     of such party in this Agreement or any Credit Support Document proves to 
     have been incorrect or misleading in any material respect when made or 
     repeated or deemed to have been made or repeated;

     (v)   Default under Specified Transaction. The party, any Credit Support 
     Provider of such party or any applicable Specified Entity of such party 
     (1) defaults under a Specified Transaction and, after giving effect to 
     any applicable notice requirement or grace period, there occurs a 
     liquidation of, an acceleration of obligations under, or an early 
     termination of, that Specified Transaction, (2) defaults, after giving 
     effect to any applicable notice requirement or grace period, in making 
     any payment or delivery due on the last payment, delivery or exchange 
     date of, or any payment on early termination of, a Specified Transaction 
     (or such default continues for at least three Local Business Days if 
     there is no applicable notice requirement or grace period) or (3) 
     disaffirms, disclaims, repudiates or rejects, in whole or in part, a 
     Specified Transaction (or such action is taken by any person or entity 
     appointed or empowered to operate it or act on its behalf);

     (vi)  Cross Default. If "Cross Default" is specified in the Schedule as 
     applying to the party, the occurrence or existence of (1) a default, 
     event of default or other similar condition or event (however described) 
     in respect of such party, any Credit Support Provider of such party or 
     any applicable Specified Entity of such party under one or more 
     agreements or instruments relating to Specified Indebtedness of any of 
     them (individually or collectively) in an aggregate amount of not less 
     than the applicable Threshold Amount (as specified in the Schedule) 
     which has resulted in such Specified Indebtedness becoming, or becoming 
     capable at such time of being declared, due and payable under such 
     agreements or instruments, before it would otherwise have been due and 
     payable or (2) a default by such party, such Credit Support Provider or 
     such Specified Entity (individually or collectively) in making one or 

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     more payments on the due date thereof in an aggregate amount of not less 
     than the applicable Threshold Amount under such agreements or 
     instruments (after giving effect to any applicable notice requirement or 
     grace period);

     (vii) Bankruptcy. The party, any Credit Support Provider of such party 
     or any applicable Specified Entity of such party: -

          (1)  is dissolved (other than pursuant to a consolidation, 
          amalgamation or merger); (2) becomes insolvent or is unable to pay 
          its debts or fails or admits in writing its inability generally to 
          pay its debts as they become due; (3) makes a general assignment, 
          arrangement or composition with or for the benefit of its creditors;
          (4) institutes or has instituted against it a proceeding seeking a 
          judgment of insolvency or bankruptcy or any other relief under any 
          bankruptcy or insolvency law or other similar law affecting 
          creditors' rights, or a petition is presented for its winding-up or 
          liquidation, and, in the case of any such proceeding or petition 
          instituted or presented against it, such proceeding or petition (A) 
          results in a judgment of insolvency or bankruptcy or the entry of an
          order for relief or the making of an order for its winding-up or 
          liquidation or (B) is not dismissed, discharged, stayed or 
          restrained in each case within 30 days of the institution or 
          presentation thereof; (5) has a resolution passed for its winding-
          up, official management or liquidation (other than pursuant to a 
          consolidation, amalgamation or merger); (6) seeks or becomes subject 
          to the appointment of an administrator, provisional liquidator, 
          conservator, receiver, trustee, custodian or other similar official 
          for it or for all or substantially all its assets; (7) has a secured
          party take possession of all or substantially all its assets or has 
          a distress, execution, attachment, sequestration or other legal 
          process levied, enforced or sued on or against all or substantially 
          all its assets and such secured party maintains possession, or any 
          such process is not dismissed, discharged, stayed or restrained, in 
          each case within 30 days thereafter; (8) causes or is subject to any 
          event with respect to it which, under the applicable laws of any 
          jurisdiction, has an analogous effect to any of the events specified 
          in clauses (1) to (7) (inclusive); or (9) takes any action in 
          furtherance of, or indicating its consent to, approval of, or 
          acquiescence in, any of the foregoing acts; or

     (viii) Merger Without Assumption. The party or any Credit Support 
     Provider of such party consolidates or amalgamates with, or merges with 
     or into, or transfers all or substantially all its assets to, another 
     entity and, at the time of such consolidation, amalgamation, merger or 
     transfer: -

          (1)  the resulting, surviving or transferee entity fails to assume 
          all the obligations of such party or such Credit Support Provider 
          under this Agreement or any Credit Support Document to which it or 
          its predecessor was a party by operation of law or pursuant to an 
          agreement reasonably satisfactory to the other party to this 
          Agreement; or


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          (2)  the benefits of any Credit Support Document fail to extend 
          (without the consent of the other party) to the performance by such 
          resulting, surviving or transferee entity of its obligations under 
          this Agreement.

(b)  Termination Events. The occurrence at any time with respect to a party 
or, if applicable, any Credit Support Provider of such party or any Specified 
Entity of such party of any event specified below constitutes an Illegality if 
the event is specified in (i) below, and, if specified to be applicable, a 
Credit Event Upon Merger if the event is specified pursuant to (ii) below or 
an Additional Termination Event if the event is specified pursuant to (iii) 
below: -

     (i)   Illegality. Due to the adoption of, or any change ii), any 
     applicable law after the date on which a Transaction is entered into, 
     or due to the promulgation of, or any change in, the interpretation by 
     any court, tribunal or regulatory authority with competent jurisdiction 
     of any applicable law after such date, it becomes unlawful (other than 
     as a result of a breach by the party of Section 4(b)) for such party 
     (which will be the Affected Party): -

          (1)  to perform any absolute or contingent obligation to make a 
          payment or delivery or to receive a payment or delivery in respect 
          of such Transaction or to comply with any other material provision 
          of this Agreement relating to such Transaction; or

          (2)  to perform, or for any Credit Support Provider of such party to
          perform, any contingent or other obligation which the party (or such
          Credit Support Provider) has under any Credit Support Document 
          relating to such Transaction;

     (ii)  Credit Event Upon Merger. If "Credit Event Upon Merger" is 
     specified in the Schedule as applying to the party, such party ("X"), 
     any Credit Support Provider of X or any applicable Specified Entity of 
     X consolidates or amalgamates with, or merges with or into, or 
     transfers all or substantially all its assets to, another entity and 
     such action does not constitute an event described in Section 
     5(a)(viii) but the creditworthiness of the resulting, surviving or 
     transferee entity is materially weaker than that of X, such Credit 
     Support Provider or such Specified Entity, as the case may be, 
     immediately prior to such action (and, in such event, X or its 
     successor or transferee, as appropriate, will be the Affected Party); 
     or

     (iii) Additional Termination Event. If any "Additional Termination 
     Event" is specified in the Schedule or any Confirmation as applying, 
     the occurrence of such event (and, in such event, the Affected Party or 
     Affected Parties shall be as specified for such Additional Termination 
     Event in the Schedule or such Confirmation).

(c)  Event of Default and Illegality. If an event or circumstance which would 
otherwise constitute or give rise to an Event of Default also constitutes an 
Illegality, it will be treated as an Illegality and will not constitute an 
Event of Default.

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6.   Early Termination

(a)  Right to Terminate Following Event of Default. If at any time an Event of 
Default with respect to a party (the "Defaulting Party") has occurred and is 
then continuing, the other party (the "Non-defaulting Party") may, by not more 
than 20 days notice to the Defaulting Party specifying the relevant Event of 
Default, designate a day not earlier than the day such notice is effective as 
an Early Termination Date in respect of all outstanding Transactions. If, 
however, "Automatic Early Termination" is specified in the Schedule as 
applying to a party, then an Early Termination Date in respect of all 
outstanding Transactions will occur immediately upon the occurrence with 
respect to such party of an Event of Default specified in Section 
5(a)(vii)(1), (3), (5), (6) or, to the extent analogous thereto, (8), and as 
of the time immediately preceding the institution of the relevant proceeding 
or the presentation of the relevant petition upon the occurrence with respect 
to such party of an Event of Default specified in Section 5(a)(vii)(4) or, to 
the extent analogous thereto, (8).

(b)  Right to Terminate Following Termination Event.

     (i)   Notice. If a Termination Event occurs, an Affected Party will, 
     promptly upon becoming aware of it, notify the other party, specifying 
     the nature of that Termination Event and each Affected Transaction and 
     will also give such other information about that Termination Event as 
     the other party may reasonably require.

     (ii)  Two Affected Parties. If an Illegality under Section 5(b)(i)(1) 
     occurs and there are two Affected Parties, each party will use all 
     reasonable efforts to reach agreement within 30 days after notice 
     thereof is given under Section 6(b)(i) on action to avoid that 
     Termination Event.

     (iii) Right to Terminate. If: -

          (1)  an agreement under Section 6(b)(ii) has not been effected with 
          respect to all Affected Transactions within 30 days after an 
          Affected Party gives notice under Section 6(b)(i); or

          (2)  an Illegality other than that referred to in Section 6(b)(ii), 
          a Credit Event Upon Merger or an Additional Termination Event 
          occurs,

     either party in the case of an Illegality, any Affected Party in the 
     case of an Additional Termination Event if there is more than one 
     Affected Party, or the party which is not the Affected Party in the 
     case of a Credit Event Upon Merger or an Additional Termination Event 
     if there is only one Affected Party may, by not more than 20 days 
     notice to the other party and provided that the relevant Termination 
     Event is then continuing, designate a day not earlier than the day such 
     notice is effective as an Early Termination Date in respect of all 
     Affected Transactions.




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(c)  Effect of Designation.

     (i)   If notice designating an Early Termination Date is given under 
     Section 6(a) or (b), the Early Termination Date will occur on the date 
     so designated, whether or not the relevant Event of Default or 
     Termination Event is then continuing.

     (ii)  Upon the occurrence or effective designation of an Early 
     Termination Date, no further payments or deliveries under Section 
     2(a)(i) or 2(d) in respect of the Terminated Transactions will be 
     required to be made, but without prejudice to the other provisions of 
     this Agreement. The amount, if any, payable in respect of an Early 
     Termination Date shall be determined pursuant to Section 6(e).

(d)  Calculations.

     (i)   Statement. On or as soon as reasonably practicable following the 
     occurrence of an Early Termination Date, each party will make the 
     calculations on its part, if any, contemplated by Section 6(e) and will 
     provide to the other party a statement (1) showing, in reasonable 
     detail, such calculations (including all relevant quotations and 
     specifying any amount payable under Section 6(e)) and (2) giving 
     details of the relevant account to which any amount payable to it is to 
     be paid.  In the absence of written confirmation from the source of a 
     quotation obtained in determining a Market Quotation, the records of 
     the party obtaining such quotation will be conclusive evidence of the 
     existence and accuracy of such quotation.

     (ii)  Payment Date. An amount calculated as being due in respect of any 
     Early Termination Date under Section 6(e) will be payable on the day 
     that notice of the amount payable is effective (in the case of an Early 
     Termination Date which is designated or occurs as a result of an Event 
     of Default) and on the day which is two Local Business Days after the 
     day on which notice of the amount payable is effective (in the case of 
     an Early Termination Date which is designated as a result of a 
     Termination Event). Such amount will be paid together with (to the 
     extent permitted under applicable law) interest thereon (before as well 
     as after judgment), from (and including) the relevant Early Termination 
     Date to (but excluding) the date such amount is paid, at the Applicable 
     Rate. Such interest will be calculated on the basis of daily 
     compounding and the actual number of days elapsed.

(e)  Payments on Early Termination. If an Early Termination Date occurs, the 
following provisions shall apply based on the parties' election in the 
Schedule of a payment measure, either "Market Quotation" or "Loss", and a 
payment method, either the "First Method" or the "Second Method". If the 
parties fail to designate a payment measure or payment method in the Schedule, 
it will be deemed that "Market Quotation" or the "Second Method", as the case 
may be, shall apply. The amount, if any, payable in respect of an Early 
Termination Date and determined pursuant to this Section will be subject to 
any Set-off.

     (i)   Events of Default. If the Early Termination Date results from an 
     Event of Default: -

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          (1)  First Method and Market Quotation. If the First Method and 
          Market Quotation apply, the Defaulting Party will pay to the Non-
          defaulting Party the excess, if a positive number, of (A) the sum of 
          the Settlement Amount (determined by the Non-defaulting Party) in 
          respect of the Terminated Transactions and the Unpaid Amounts owing 
          to the Non-defaulting Party over (B)  the Unpaid Amounts owing to 
          the Defaulting Party.

          (2)  First Method and Loss. If the First Method and Loss apply, the 
          Defaulting Party will pay to the Non-defaulting Party, if a positive 
          number, the Non-defaulting Party's Loss in respect of this 
          Agreement.

          (3)  Second Method and Market Quotation. If the Second Method and 
          Market Quotation apply, an amount will be payable equal to (A) the 
          sum of the Settlement Amount (determined by the Non-defaulting 
          Party) in respect of the Terminated Transactions and the Unpaid 
          Amounts owing to the Non-defaulting Party less (B) the Unpaid 
          Amounts owing to the Defaulting Party. If that amount is a positive 
          number, the Defaulting Party will pay it to the Non-defaulting 
          Party; if it is a negative number, the Non-defaulting Party will pay 
          the absolute value of that amount to the Defaulting Party.

          (4)  Second Method and Loss. If the Second Method and Loss apply, an 
          amount will be payable equal to the Non-defaulting Party's Loss in 
          respect of this Agreement. If that amount is a positive number, the 
          Defaulting Party will pay it to the Non-defaulting Party; if it is a 
          negative number, the Non-defaulting Party will pay the absolute 
          value of that amount to the Defaulting Party.

     (ii)  Termination Events. If the Early Termination Date results from a 
     Termination Event: -

          (1)  One Affected Party. If there is one Affected Party, the amount 
          payable will be determined in accordance with Section 6(e)(i)(3), if 
          Market Quotation applies, or Section 6(e)(i)(4), if Loss applies, 
          except that, in either case, references to the Defaulting Patty and 
          to the Non-defaulting Party will be deemed to be references to the 
          Affected Party and the party which is not the Affected Party, 
          respectively, and, if Loss applies and fewer than all the 
          Transactions are being terminated, Loss shall be calculated in 
          respect of all Terminated Transactions.

          (2)  Two Affected Parties. If there are two Affected Parties: -

               (A)  if Market Quotation applies, each party will determine a 
               Settlement Amount in respect of the Terminated Transactions,
               and an amount will be payable equal to (I) the sum of (a) one-
               half of the difference between the Settlement Amount of the
               party with the higher Settlement Amount ("X") and the
               Settlement Amount of the party with the lower Settlement Amount
               ("Y") and (b) the Unpaid Amounts owing to X less (II) the
               Unpaid Amounts owing to Y; and


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               (B)  if Loss applies, each party will determine its Loss in 
               respect of this Agreement (or, if fewer than all the 
               Transactions are being terminated, in respect of all Terminated 
               Transactions) and an amount will be payable equal to one-half
               of the difference between the Loss of the party with the higher 
               Loss ("X") and the Loss of the party with the lower Loss ("Y").

          If the amount payable is a positive number, Y will pay it to X; if 
          it is a negative number, X will pay the absolute value of that 
          amount to Y.

     (iii) Adjustment for Bankruptcy. In circumstances where an Early 
     Termination Date occurs because "Automatic Early Termination" applies 
     in respect of a party, the amount determined under this Section 6(e) 
     will be subject to such adjustments as are appropriate and permitted by 
     law to reflect any payments or deliveries made by one party to the 
     other under this Agreement (and retained by such other party) during 
     the period from the relevant Early Termination Date to the date for 
     payment determined under Section 6(d)(ii).

     (iv)  Pre-Estimate. The parties agree that if Market Quotation applies 
     an amount recoverable under this Section 6(e) is a reasonable pre-
     estimate of loss and not a penalty. Such amount is payable for the loss 
     of bargain and the loss of protection against future risks and except 
     as otherwise provided in this Agreement neither party will be entitled 
     to recover any additional damages as a consequence of such losses.

7.   Transfer

Neither this Agreement nor any interest or obligation in or under this 
Agreement may be transferred (whether by way of security or otherwise) by 
either party without the prior written consent of the other party, except 
that: -

(a)  a party may make such a transfer of this Agreement pursuant to a 
consolidation or amalgamation with, or merger with or into, or transfer of all 
or substantially all its assets to, another entity (but without prejudice to 
any other right or remedy under this Agreement); and

(b)  a party may make such a transfer of all or any part of its interest in 
any amount payable to it from a Defaulting Party under Section 6(e).

Any purported transfer that is not in compliance with this Section will be 
void.

8.   Miscellaneous

(a)  Entire Agreement. This Agreement constitutes the entire agreement and 
understanding of the parties with respect to its subject matter and supersedes 
all oral communication and prior writings with respect thereto.

(b)  Amendments. No amendment, modification or waiver in respect of this 
Agreement will be effective unless in writing (including a writing evidenced 


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by a facsimile transmission) and executed by each of the parties or confirmed 
by an exchange of telexes or electronic messages on an electronic messaging 
system.

(c)  Survival of Obligations. Without prejudice to Sections 2(a)(iii) and 
6(c)(ii), the obligations of the parties under this Agreement will survive the 
termination of any Transaction.

(d)  Remedies Cumulative. Except as provided in this Agreement, the rights, 
powers, remedies and privileges provided in this Agreement are cumulative and 
not exclusive of any rights, powers, remedies and privileges provided by law.

(e)  Counterparts and Confirmations.

     (i)   This Agreement (and each amendment, modification and waiver in 
     respect of it) may be executed and delivered in counterparts (including 
     by facsimile transmission), each of which will be deemed an original.

     (ii)  The parties intend that they are legally bound by the terms of 
     each Transaction from the moment they agree to those terms (whether 
     orally or otherwise). A Confirmation shall be entered into as soon as 
     practicable and may be executed and delivered in counterparts 
     (including by facsimile transmission) or be created by an exchange of 
     telexes or by an exchange of electronic messages on an electronic 
     messaging system, which in each case will be sufficient for all 
     purposes to evidence a binding supplement to this Agreement. The 
     parties will specify therein or through another effective means that 
     any such counterpart, telex or electronic message constitutes a 
     Confirmation.

(f)  No Waiver of Rights. A failure or delay in exercising any right, power or 
privilege in respect of this Agreement will not be presumed to operate as a 
waiver, and a single or partial exercise of any right, power or privilege will 
not be presumed to preclude any subsequent or further exercise, of that right, 
power or privilege or the exercise of any other right, power or privilege.

(g)  Headings. The headings used in this Agreement are for convenience of 
reference only and are not to affect the construction of or to be taken into 
consideration in interpreting this Agreement.

9.   Expenses

A Defaulting Party will, on demand, indemnify and hold harmless the other 
party for and against all reasonable out-of-pocket expenses, including legal 
fees, incurred by such other party by reason of the enforcement and protection 
of its rights under this Agreement or any Credit Support Document to which the 
Defaulting Party is a party or by reason of the early termination of any 
Transaction, including, but not limited to, costs of collection.

10.  Notices

(a)  Effectiveness. Any notice or other communication in respect of this 
Agreement may be given in any manner set forth below (except that a notice or 
other communication under Section 5 or 6 may not be given by facsimile 

                                     12
<PAGE>   13
transmission or electronic messaging system) to the address or number or in 
accordance with the electronic messaging system details provided (see the 
Schedule) and will be deemed effective as indicated: -

     (i)   if in writing and delivered in person or by courier, on the date 
     it is delivered;

     (ii)  if sent by telex, on the date the recipient's answer back is 
     received;

     (iii) if sent by facsimile transmission, on the date that transmission 
     is received by a responsible employee of the recipient in legible form 
     (it being agreed that the burden of proving receipt will be on the 
     sender and will not be met by a transmission report generated by the 
     sender's facsimile machine);

     (iv)  if sent by certified or registered mail (airmail, if overseas) or 
     the equivalent (return receipt requested), on the date that mail is 
     delivered or its delivery is attempted; or

     (v)   if sent by electronic messaging system, on the date that 
     electronic message is received,

unless the date of that delivery (or attempted delivery) or that receipt, as 
applicable, is not a Local Business Day or that communication is delivered (or 
attempted) or received, as applicable, after the close of business on a Local 
Business Day, in which case that communication shall be deemed given and 
effective on the first following day that is a Local Business Day.

(b)  Change of Addresses. Either party may by notice to the other change the 
address, telex or facsimile number or electronic messaging system details at 
which notices or other communications are to be given to it.

11.  Governing Law and Jurisdiction

(a)  Governing Law. This Agreement will be governed by and construed in 
accordance with the law specified in the Schedule.

(b)  Jurisdiction. With respect to any suit, action or proceedings relating to 
this Agreement ("Proceedings"), each party irrevocably:-

     (i)   submits to the jurisdiction of the English courts, if this 
     Agreement is expressed to be governed by English law, or to the non-
     exclusive jurisdiction of the courts of the State of New York and the 
     United States District Court located in the Borough of Manhattan in New 
     York City, if this Agreement is expressed to be governed by the laws of 
     the State of New York; and

     (ii)  waives any objection which it may have at any time to the laying 
     of venue of any Proceedings brought in any such court, waives any claim 
     that such Proceedings have been brought in an inconvenient forum and 
     further waives the right to object, with respect to such Proceedings, 
     that such court does not have any jurisdiction over such party.


                                     13
<PAGE>   14
Nothing in this Agreement precludes either party from bringing Proceedings in 
any other jurisdiction (outside, if this Agreement is expressed to be governed 
by English law, the Contracting States, as defined in Section 1(3) of the 
Civil Jurisdiction and Judgments Act 1982 or any modification, extension or 
re-enactment thereof for the time being in force) nor will the bringing of 
Proceedings in any one or more jurisdictions preclude the bringing of 
Proceedings in any other jurisdiction.

(c)  Waiver of Immunities. Each party irrevocably waives, to the fullest 
extent permitted by applicable law, with respect to itself and its revenues 
and assets (irrespective of their use or intended use), all immunity on the 
grounds of sovereignty or other similar grounds from (i) suit, (ii) 
jurisdiction of any court, (iii) relief by way of injunction, order for 
specific performance or for recovery of property, (iv) attachment of its 
assets (whether before or after judgment) and (v) execution or enforcement of 
any judgment to which it or its revenues or assets might otherwise be entitled 
in any Proceedings in the courts of any jurisdiction and irrevocably agrees, 
to the extent permitted by applicable law, that it will not claim any such 
immunity in any Proceedings.

12.  Definitions

As used in this Agreement: -"Additional Termination Event" has the meaning 
specified in Section 5(b).

"Affected Party" has the meaning specified in Section 5(b).

"Affected Transactions" means (a) with respect to any Termination Event 
consisting of an Illegality, all Transactions affected by the occurrence of 
such Termination Event and (b) with respect to any other Termination Event, 
all Transactions.

"Affiliate" means, subject to the Schedule, in relation to any person, any 
entity controlled, directly or indirectly, by the person, any entity that 
controls, directly or indirectly, the person or any entity directly or 
indirectly under common control with the person. For this purpose, "control" 
of any entity or person means ownership of a majority of the voting power of 
the entity or person.

"Applicable Rate" means: -

(a)  in respect of obligations payable or deliverable (or which would have 
been but for Section 2(a)(iii)) by a Defaulting Party, the Default Rate;

(b)  in respect of an obligation to pay an amount under Section 6(e) of either 
party from and after the date (determined in accordance with Section 6(d)(ii)) 
on which that amount is payable, the Default Rate;

(c)  in respect of all other obligations payable or deliverable (or which 
would have been but for Section 2(a)(iii)) by a Non-defaulting Party, the Non-
default Rate; and

(d)  in all other cases, the Termination Rate.


                                     14
<PAGE>   15
"consent" includes a consent, approval, action, authorization, exemption, 
notice, filing, registration or exchange control consent.

"Credit Event Upon Merger" has the meaning specified in Section 5(b).

"Credit Support Document" means any agreement or instrument that is specified 
as such in this Agreement. 

"Credit Support Provider" has the meaning specified in the Schedule.

"Default Rate" means a rate per annum equal to the cost (without proof or 
evidence of any actual cost) to the relevant payee (as certified by it) if it 
were to fund or of funding the relevant amount plus 1% per annum.

"Defaulting Party" has the meaning specified in Section 6(a).

"Early Termination Date" means the date determined in accordance with Section 
6(a) or 6(b)(iii).

"Event of Default" has the meaning specified in Section 5(a) and, if 
applicable, in the Schedule.

"Illegality" has the meaning specified in Section 5(b).

"law" includes any treaty, law, rule or regulation and "lawful" and "unlawful" 
will be construed accordingly.

"Local Business Day" means, subject to the Schedule, a day on which commercial 
banks are open for business (including dealings in foreign exchange and 
foreign currency deposits) (a) in relation to any obligation under Section 
2(a)(i), in the place(s) specified in the relevant Confirmation or, if not so 
specified, as otherwise agreed by the parties in writing or determined 
pursuant to provisions contained, or incorporated by reference, in this 
Agreement, (b) in relation to any other payment, in the place where the 
relevant account is located, (c) in relation to any notice or other 
communication, including notice contemplated under Section 5(a)(i), in the 
city specified in the address for notice provided by the recipient and, in the 
case of a notice contemplated by Section 2(b), in the place where the relevant 
new account is to be located and (d) in relation to Section 5(a)(v)(2), in the 
relevant locations for performance with respect to such Specified Transaction.

"Loss" means, with respect to this Agreement or one or more Terminated 
Transactions, as the case may be, and a party, an amount that party reasonably 
determines in good faith to be its total losses and costs (or gain, in which 
case expressed as a negative number) in connection with this Agreement or that 
Terminated Transaction or group of Terminated Transactions, as the case may 
be, including any loss of bargain, cost of funding or, at the election of such 
party but without duplication, loss or cost incurred as a result of its 
terminating, liquidating, obtaining or reestablishing any hedge or related 
trading position (or any gain resulting from any of them). Loss includes 
losses and costs (or gains) in respect of any payment or delivery required to 
have been made (assuming satisfaction of each applicable condition precedent) 
on or before the relevant Early Termination Date and not made, except, so as 


                                     15
<PAGE>   16
to avoid duplication, if Section 6(e)(i)(1) or (3) or 6(e)(ii)(2)(A) applies. 
Loss does not include a party's legal fees and out-of-pocket expenses referred 
to under Section 9. A party will determine its Loss as of the relevant Early 
Termination Date, or, if that is not reasonably practicable, as of the 
earliest date thereafter as is reasonably practicable. A party may (but need 
not) determine its Loss by reference to quotations of relevant rates or prices 
from one or more leading dealers in the relevant markets.

"Market Quotation" means, with respect to one or more Terminated Transactions 
and a party making the determination, an amount determined on the basis of 
quotations from Reference Market-makers.  Each quotation will be for an 
amount, if any, that would be paid to such party (expressed as a negative 
number) or by such party (expressed as a positive number) in consideration of 
an agreement between such party (taking into account any existing Credit 
Support Document with respect to the obligations of such party) and the 
quoting Reference Market-maker to enter into a transaction (the "Replacement 
Transaction") that would have the effect of preserving for such party the 
economic equivalent of any payment or delivery (whether the underlying 
obligation was absolute or contingent and assuming the satisfaction of each 
applicable condition precedent) by the parties under Section 2(a)(i) in 
respect of such Terminated Transaction or group of Terminated Transactions 
that would, but for the occurrence of the relevant Early Termination Date, 
have been required after that date. For this purpose, Unpaid Amounts in 
respect of the Terminated Transaction or group of Terminated Transactions are 
to be excluded but, without limitation, any payment or delivery that would, 
but for the relevant Early Termination Date, have been required (assuming 
satisfaction of each applicable condition precedent) after that Early 
Termination Date is to be included. The Replacement Transaction would be 
subject to such documentation as such party and the Reference Market-maker 
may, in good faith, agree. The party making the determination (or its agent) 
will request each Reference Market-maker to provide its quotation to the 
extent reasonably practicable as of the same day and time (without regard to 
different time zones) on or as soon as reasonably practicable after the 
relevant Early Termination Date. The day and time as of which those quotations 
are to be obtained will be selected in good faith by the party obliged to make 
a determination under Section 6(e), and, if each party is so obliged, after 
consultation with the other. If more than three quotations are provided, the 
Market Quotation will be the arithmetic mean of the quotations, without regard 
to the quotations having the highest and lowest values. If exactly three such 
quotations are provided, the Market Quotation will be the quotation remaining 
after disregarding the highest and lowest quotations. For this purpose, if 
more than one quotation has the same highest value or lowest value, then one 
of such quotations shall be disregarded. If fewer than three quotations are 
provided, it will be deemed that the Market Quotation in respect of such 
Terminated Transaction or group of Terminated Transactions cannot be 
determined.

"Non-default Rate" means a rate per annum equal to the cost (without proof or 
evidence of any actual cost) to the Non-defaulting Party (as certified by it) 
if it were to fund the relevant amount.

"Non-defaulting Party" has the meaning specified in Section 6(a).



                                     16
<PAGE>   17
"Potential Event of Default" means any event which, with the giving of notice 
or the lapse of time or both, would constitute an Event of Default.

"Reference Market-makers" means four leading dealers in the relevant market 
selected by the party determining a Market Quotation in good faith (a) from 
among dealers of the highest credit standing which satisfy all the criteria 
that such party applies generally at the time in deciding whether to offer or 
to make an extension of credit and (b) to the extent practicable, from among 
such dealers having an office in the same city.

"Scheduled Payment Date" means a date on which a payment or delivery is to be 
made under Section 2(a)(i) with respect to a Transaction.

"Set-off" means set-off, offset, combination of accounts, right of retention 
or withholding or similar right or requirement to which the payer of an amount 
under Section 6 is entitled or subject (whether arising under this Agreement, 
another contract, applicable law or otherwise) that is exercised by, or 
imposed on, such payer.

"Settlement Amount" means, with respect to a party and any Early Termination 
Date, the sum of: -

(a)  the Market Quotations (whether positive or negative) for each Terminated 
Transaction or group of Terminated Transactions for which a Market Quotation 
is determined; and

(b)  such party's Loss (whether positive or negative and without reference to 
any Unpaid Amounts) for each Terminated Transaction or group of Terminated 
Transactions for which a Market Quotation cannot be determined or would not 
(in the reasonable belief of the party making the determination) produce a 
commercially reasonable result.

"Specified Entity" has the meaning specified in the Schedule.

"Specified Indebtedness" means, subject to the Schedule, any obligation 
(whether present or future, contingent or otherwise, as principal or surety or 
otherwise) in respect of borrowed money.

"Specified Transaction" means, subject to the Schedule, (a) any transaction 
(including an agreement with respect thereto) now existing or hereafter 
entered into between one party to this Agreement (or any Credit Support 
Provider of such party or any applicable Specified Entity of such party) and 
the other party to this Agreement (or any Credit Support Provider of such 
other party or any applicable Specified Entity of such other party) which is a 
rate swap transaction, basis swap, forward rate transaction, commodity swap, 
commodity option, equity or equity index swap, equity or equity index option, 
bond option, interest rate option, foreign exchange transaction, cap 
transaction, floor transaction, collar transaction, currency swap transaction, 
cross-currency rate swap transaction, currency option or any other similar 
transaction (including any option with respect to any of these transactions), 
(b) any combination of these transactions and (c) any other transaction 
identified as a Specified Transaction in this Agreement or the relevant 
confirmation.


                                     17
<PAGE>   18
"Terminated Transactions" means with respect to any Early Termination Date (a) 
if resulting from a Termination Event, all Affected Transactions and (b) if 
resulting from an Event of Default, all Transactions (in either case) in 
effect immediately before the effectiveness of the notice designating that 
Early Termination Date (or, if "Automatic Early Termination" applies, 
immediately before that Early Termination Date).

"Termination Event" means an Illegality or, if specified to be applicable, a 
Credit Event Upon Merger or an Additional Termination Event.

"Termination Rate" means a rate per annum equal to the arithmetic mean of the 
cost (without proof or evidence of any actual cost) to each party (as 
certified by such party) if it were to fund or of funding such amounts.

"Unpaid Amounts" owing to any party means, with respect to an Early 
Termination Date, the aggregate of (a) in respect of all Terminated 
Transactions, the amounts that became payable (or that would have become 
payable but for Section 2(a)(iii)) to such party under Section 2(a)(i) on or 
prior to such Early Termination Date and which remain unpaid as at such Early 
Termination Date and (b) in respect of each Terminated Transaction, for each 
obligation under Section 2(a)(i) which was (or would have been but for Section 
2(a)(iii)) required to be settled by delivery to such party on or prior to 
such Early Termination Date and which has not been so settled as at such Early 
Termination Date, an amount equal to the fair market value of that which was 
(or would have been) required to be delivered as of the originally scheduled 
date for delivery, in each case together with (to the extent permitted under 
applicable law) interest, in the currency of such amounts, from (and 
including) the date such amounts or obligations were or would have been 
required to have been paid or performed to (but excluding) such Early 
Termination Date, at the Applicable Rate. Such amounts of interest will be 
calculated on the basis of daily compounding and the actual number of days 
elapsed. The fair market value of any obligation referred to in clause (b) 
above shall be reasonably determined by the party obliged to make the 
determination under Section 6(e) or, if each party is so obliged, it shall be 
the average of the fair market values reasonably determined by both parties.


IN WITNESS WHEREOF the parties have executed this document on the respective 
dates specified below with effect from the date specified on the first page of 
this document.


      CORESTATES BANK, N.A.                UNITED STATES LIME & MINERALS, INC.
    ----------------------------          ------------------------------------
        (Name of Party)                          (Name of Party)


By:  \s\ William T. Breesmen              By:  \s\ F. Gene Winfield
    ----------------------------              -----------------------------
    Name:  William T. Breesmen                Name:  F. Gene Winfield 
    Title: Vice President                     Title: Treasurer
   Date:  April 3, 1998                      Date:  April 22, 1998


                                     18
<PAGE>   19
                                   SCHEDULE
                                    to the
                               MASTER AGREEMENT
                      dated as of April 3, 1998 between
                      CORESTATES BANK, N.A. ("Party A")
             and UNITED STATES LIME & MINERALS, INC. ("Party B")

I.  Termination Provisions
    ----------------------
(a)  "Specified Entity" for purposes of Section 5(a)(v) means each party's 
     Affiliates. If a party or any Credit Support Provider of a party is a 
     partnership, then for purposes of Sections 5(a)(v), 5(a)(vi), 5(a)(vii) 
     and 5(b)(ii), "Specified Entity" also means each general partner of that 
     partnership:

(b)  "Specified Transaction" has its meaning as defined in Section 12, 
     provided that "Default under Specified Transaction" excludes Force 
     Majeure as defined below.

(c)  "Cross Default" applies to both parties, but excludes Force Majeure. 
     "Force Majeure" means nonpayment resulting solely from a wire transfer or 
     operational problem or error (so long as sufficient funds are available), 
     or from the general unavailability of the relevant currency due to 
     exchange controls or other similar governmental action, but only if 
     payment is made within three Business Days after the problem has been 
     corrected, the error has been discovered or the currency becomes 
     available.

     With respect to Party B, "Cross Default" is amended by inserting at the 
     end of Section 5(a)(vi): "or (3) any default, event of default or other 
     similar condition or event (however described) under any Financial 
     Agreement."

     "Specified Indebtedness" means any obligation (whether present, future, 
     contingent or otherwise, as principal or surety or otherwise) in respect 
     of borrowed money or relating to the payment or delivery of funds, 
     securities or other property (including, without limitation, collateral).

     "Threshold Amount" means, with respect to Party A, an amount (including 
     its equivalent in another currency) equal to the higher of $10,000,000 or 
     2% of its stockholders' equity as reflected on its most recent financial 
     statements or call reports, and with respect to Party B, any amount of 
     Specified Indebtedness.

(d)  "Credit Event Upon Merger" applies to both parties.

(e)  "Automatic Early Termination" does not apply to either party.

(f)  Payments on Early Termination. "Market Quotation" and the "Second Method" 
     apply, subject to the following:

     (i)  "Market Quotation" for any Terminated Transaction that is, or is 
     subject to, any unexercised option shall be determined by taking into 
     account the economic equivalent of the option.

                                      1
<PAGE>   20
     (ii)  The Non-defaulting Party may, upon the occurrence of an Early 
     Termination Date, offset payments due by it under this Agreement (or 
     under any Specified Transaction) against, and apply such payments to the 
     satisfaction of, any obligations owing by the Defaulting Party (including 
     any Office of the Defaulting Party) to the Non-defaulting Party or any of 
     the Non-defaulting Party's Affiliates (including any Office of the Non-
     defaulting Party or its Affiliates) whether matured or unmatured, and it 
     is a condition precedent to the Non-defaulting Party's obligation to make 
     any such payments that such obligations of the Defaulting Party have been 
     paid in full or satisfied by offset as contemplated hereunder. For this 
     purpose, the Non-defaulting Party may convert any such payments or 
     obligations into the currency of the other at a rate of exchange 
     (including premiums and costs of exchange) at which it could purchase the 
     relevant currency acting in good faith.

II.  Documents
     ---------
(a)  Delivery of Documents. When it delivers this Agreement, Party B shall 
     also deliver to Party A the Closing Documents in form and substance 
     reasonably satisfactory to Party A. For each Transaction, Party B shall 
     deliver, promptly upon request, a duly executed incumbency certificate
     for the person(s) executing the Confirmation for Party B for that
     Transaction.

(b)  "Closing Documents" means an opinion of counsel covering Party B's Basic 
     Representations under Section 3(a), or in lieu thereof, Party B's 
     Authorizing Documents for this Agreement and the Transaction(s) and a 
     duly executed incumbency certificate for the person(s) executing this 
     Agreement for Party B.

(c)  "Authorizing Documents" of a party or its Credit Support Provider means a 
     certified copy of the board of directors' resolutions of that party' or 
     Credit Support Provider (or for a partnership, a copy of its partnership 
     agreement and a certified copy of the resolutions of the partnership or 
     of each general partner).

III.  Miscellaneous
      -------------
(a)  Addresses for Notices.

     To Party A:                      To Party B:

     CORESTATES BANK, N.A.            UNITED STATES LIME & MINERALS, INC.

     1500 Market Street               12221 Merit Drive, Suite 500
     Center Square West               Dallas, TX 75251

     P.O. Box 7618
     FC 1-3-91-8
     Philadelphia, PA 19101-7618

     Attention:  Wendy Havens         Attention:  Gene Winfield

     Fax:   (215) 973-8388            Fax:   (972) 385-1340
     Phone: (215) 973-2385            Phone: (972) 991-8400

                                      2
<PAGE>   21
(b)  "Calculation Agent" means Party A.

(c)  "Credit Support Document" means each document which by its terms secures, 
     guarantees or otherwise supports Party' B's obligations hereunder from 
     time to time, whether or not this Agreement, any Transaction, or any type 
     of Transaction entered into hereunder is specifically referenced or 
     described in any such document.

     "Credit Support Default" is amended by adding at the end of Section 
     5(a)(iii)(1):

     ", any default, event of default or other similar condition or event 
     (however described) exists under any Credit Support Document, any action 
     is taken to realize upon any collateral provided to secure such party's 
     obligations hereunder or under any Transaction, or the other party fails 
     at any time to have a valid and perfected first priority security
     interest in any such collateral;"

(d)  "Credit Support Provider" means each party' to a Credit Support Document 
     that provides or is obligated to provide security, a guaranty or other 
     credit support for Party B's obligations hereunder.

(e)  "Affiliate" has its meaning as defined in Section 12, except for Party A 
     under Section 5(a)(v), "Affiliate" means CoreStates Financial 
     Corporation.

(f)  Governing Law. This Agreement will be governed by and construed in 
     accordance with the law (and not the law of conflicts) of the State of 
     New York.

(g)  Waiver of Jury Trial. To the extent permitted by applicable law, each 
     party irrevocably waives any and all right to trial by jury in any legal 
     proceeding in connection with this Agreement, any Credit Support Document 
     to which it is a party, or any Transaction.

(h)  Netting of Payments. If payments are due by each party on the same day 
     under two or more Transactions, then Section 2(c)(ii) will not apply to 
     those payments if a party gives notice to the relevant Office(s) of the 
     other party on or before the second New York Business Day before that 
     payment date stating that those payments will be netted or, if given by 
     the Calculation Agent, stating the net amount due.

(i)  Recorded Conversations. Each party may electronically record all 
     telephone conversations between them in connection with this Agreement or 
     any Transaction, and any such recordings may be submitted in evidence in 
     any proceeding to establish any matters pertinent to this Agreement or 
     any Transaction.

(j)  Additional Representations. Section 3 is amended by adding the following 
     Sections 3(e) and 3(f):

     "(e) for any Relevant Agreement: (i) it acts as principal and not as 
     agent, (ii) it acknowledges that the other party acts only at arm's 
     length and is not its agent, broker, advisor or fiduciary in any respect, 

                                      3
<PAGE>   22
     and any agency, brokerage, advisory or fiduciary services that the other 
     party (or any of its affiliates) may otherwise provide to the party (or 
     to any of its affiliates) excludes the Relevant Agreement, (iii) it is 
     relying solely upon its own evaluation of the Relevant Agreement 
     (including the present and future results, consequences, risks, and 
     benefits thereof, whether financial, accounting, tax, legal, or 
     otherwise) and upon advice from its own professional advisors, (iv) it 
     understands the Relevant Agreement and those risks, has determined they 
     are appropriate for it, and willingly assumes those risks, and (v) it has 
     not relied and will not be relying upon any evaluation or advice 
     (including any recommendation, opinion, or representation) from the other 
     party, its affiliates or the representatives or advisors of the other 
     party or its affiliates (except representations expressly made in the 
     Relevant Agreement or an opinion of counsel required thereunder).

     "Relevant Agreement" means this Agreement, each Transaction, each 
     Confirmation, any Credit Support Document, and any agreement (including 
     any amendment, modification, transfer or early termination) between the 
     parties relating thereto or to any Transaction.

     (f)  it is an "eligible swap participant" within the meaning of 17 C.F.R. 
     "35.1."

(k)  Joint Party. If more than one entity or natural person is executing 
     this Agreement as Party B, then (i) the obligations of Party B hereunder 
     and under each Transaction shall be the joint and several obligations of 
     each such entity or natural person, (ii) any Event of Default or 
     Potential Event of Default occurring with respect to any such entity or 
     natural person shall be an Event of Default or Potential Event of 
     Default, respectively, with respect to Party B, (iii) the death, release 
     or discharge, in whole or in part, of any such entity or natural person, 
     or the occurrence of any bankruptcy, liquidation, dissolution or any 
     other event described in Section 5(a)(vii) with respect to any such 
     entity or natural person, shall not discharge or affect the liabilities 
     of any other such entity or natural person; (iv) unless the context 
     otherwise requires, each reference herein or in any Confirmation to 
     "party" shall, as applied to Party B, be construed as a joint and 
     several reference to each such entity or natural person; and (v) any 
     person or entity receiving notices given to Party B at the address shown 
     above shall be deemed to receive such notices on behalf of each such 
     entity or person.

IV.  ISDA Definitions
     ----------------
(a)  Incorporation. This Agreement and each Transaction are subject to the 
     1991 ISDA Definitions (as published by the International Swaps and 
     Derivatives Association, Inc.) and will be governed by the provisions of 
     the ISDA Definitions, without regard to any amendments to the ISDA 
     Definitions subsequent to the date hereof. The provisions of the ISDA 
     Definitions are incorporated by reference in, and shall be deemed to be 
     part of, this document and each Confirmation.

(b)  Inconsistency. In the event of any inconsistency between the provisions 
     of this document and the ISDA Definitions, this document will prevail.

                                      4
<PAGE>   23
V.  Additional Terms
    ----------------
(a)  Covenants of Financial Agreements. (i) Party B shall provide Party A at 
     all times hereunder with the same covenant protection as Party A requires 
     of Party B under Financial Agreements. Therefore, in addition to the 
     Cross Default provisions of this Agreement, and notwithstanding the 
     satisfaction of any obligation or promise to pay money to Party A under 
     any Financial Agreement, or the termination or cancellation of any 
     Financial Agreement, Party B hereby agrees to perform, comply with and 
     observe for the benefit of Party A hereunder all affirmative and negative 
     covenants contained in each Financial Agreement applicable to Party B 
     (excluding any obligation or promise to pay money under any Financial 
     Agreement) at any time Party B has any obligation (whether absolute or 
     contingent) under this Agreement.

     (ii)  For purposes hereof: (A) the affirmative and negative covenants of 
     each Financial Agreement applicable to Party B (together with related 
     definitions and ancillary provisions, but in any event excluding any 
     obligation or promise to pay money under any Financial Agreement) are 
     incorporated (and upon execution of any future Financial Agreement, shall 
     automatically be incorporated) by reference herein (mutatis mutandis); 
     (B) if other lenders or creditors are parties to any Financial Agreement, 
     then references therein to the lenders or creditors shall be deemed 
     references to Party A; and (C) for any such covenant applying only when 
     any loan, other extension of credit, obligation or commitment under the 
     Financial Agreement is outstanding, that covenant shall be deemed to 
     apply hereunder at any time Party B has any obligation (whether absolute 
     or contingent) under this Agreement.

     (iii) Notwithstanding the foregoing, if the incorporation of any 
     provision by reference from any Financial Agreement would result in the 
     violation by Party B of the terms of that Financial Agreement, this 
     Agreement shall not incorporate that provision.

(b)  "Financial Agreement" means each existing or future agreement or 
     instrument relating to any loan or extension of credit from Party A to 
     Party B (whether or not anyone else is a party thereto), as the same 
     exists when executed and without regard to any termination or 
     cancellation thereof, or unless consented to in writing by Party A, any 
     amendment, modification, addition, waiver or consent thereto or thereof.















                                      5
<PAGE>   24
IN WITNESS WHEREOF, the parties have executed this Schedule by their duly 
authorized signatories as of the date hereof.

                                 CORESTATES BANK, N.A.


                                 By:  \s\  William T. Breesmen
                                     -------------------------------
                                 Name:  William T. Breesmen
                                 Title: Vice President



                                 UNITED STATES LIME & MINERALS, INC.

                                 
                                 By:  \s\ F. Gene Winfield
                                     -------------------------------
                                 Name:  F. Gene Winfield
                                 Title: Treasurer



































                                      6
<PAGE>   25
     CoreStates Bank, N.A.
     CoreStates Capital Markets and
     Funding Operations
     P0 Box 8590
     Philadelphia PA 19101-8590



                       INTEREST RATE SWAP CONFIRMATION


UNITED STATES LIME & MINERALS. INC.
Attention:  GENE WINFIELD
12221 MERIT DRIVE
SUITE 500
DALLAS, TX  75251

Dear Customer:

The purpose of this document is to confirm the terms and conditions of the 
Rate Swap Transaction entered Into between CoreStates Bank, N.A. and UNITED 
STATES LIME & MINERALS. INC., on the contract date specified below.

The definitions and provisions contained in the 1991 ISDA Definitions (as 
published by the International Swap Dealers Association. Inc.) are 
Incorporated into this Confirmation.  In the event of any inconsistency 
between those definitions and provisions and this Confirmation. this 
Confirmation will govern.

This confirmation supplements, forms part of, and is subject to, the Interest 
Rate Agreement dated as of April 3, 1998, as amended and supplemented from 
time to time (the "Agreement"), between you and us. All provisions contained 
or incorporated by reference in the Agreement shall govern this Confirmation 
except as expressly modified below;

Notional Amount:          9,000,000.00 USD

Our Transaction No:       129410

Trade Date:               03APR98

Effective Date:           01MAY98

Termination Date:         01JUL03

FLOATING Rate Payer:      CoreStates Bank, N.A.

FIXED Rate Payer:         UNITED STATES LIME & MINERALS. INC.

Fixed Rate:               7.4500

Day Count Fraction:       ACTUAL/360



                                      1
<PAGE>   26
Payment Dates:
01JUN98, 01JUL98, 03AUG98, 01SEP98, 01OCT98, 02NOV98, 01DEC98, 04JAN99,
01FEB99, 01MAR99, 01APR99, 04MAY99, 01JUN99, 01JUL99, 02AUG99, 01SEP99,
01OCT99, 01NOV99, 01DEC99, 04JAN00, 01FEB00, 01MAR00, 03APR00, 02MAY00,
01JUN00, 03JUL00, 01AUG00, 01SEP00, 02OCT00, 01NOV00, 01DEC00, 02JAN01,
01FEB01, 01MAR01, 02APR01, 01MAY01, 01JUN01, 02JUL01, 01AUG01, 04SEP01,
01OCT01, 01N0V01, 03DEC01, 02JAN02, 01FEB02, 01MAR02, 02APR02, 01MAY02,
03JUN02, 01JUL02, 01AUG02, 03SEP02, 01OCT02, 01NOV02, 02DEC02, 02JAN03,
03FEB03, 03MAR03, 01APR03, 01MAY03, 02JUN03, 01JULO3.

Business Day Convention:  MODIFIED FOLLOWING BANK DAY

Floating Rate Option:     1M USD/BBA LIBOR

Spread:                   1.6500%

Initial Floating Rate:    TO BE SET (INCLUSIVE OF SPREAD)

Day Count Fraction:       ACTUAL/360

Reset Dates:
01MAY98, 01JUN98, 01JUL98, 03AUG98, 01SEP98, 01OCT98, 02NOV98, 01DEC98,
04JAN99, 01FEB99, 01MAR99, 01APR99, 04MAY99, 01JUN99, 01JUL99, 02AUG99,
01SEP99, 01OCT99, 01NOV99, 01DEC99, 04JAN00, 01FEB00, 01MAR00, 03APR00,
02MAY00, 01JUN00, 03JUL00, 01AUG00, 01SEP00, 02OCT00, 01NOV00, 01DEC00,
02JAN01, 01FEB01, 01MAR01, 02APR01, 01MAY01, 01JUN01, 02JUL01, 01AUG01,
04SEP01, 01OCT01, 01NOV01, 03DEC01, 02JAN02, 01FEB02, 01MAR02, 02APR02,
01MAY02, 03JUN02, 01JUL02, 01AUG02, 03SEP02, 01OCTO2, 01NOV02, 02DEC02,
02JAN03, 03FEB03, 03MAR03, 01APR03, 01MAY03, 02JUNO3.

Payment Dates:
01JUN98, 01JUL98, 03AUG98, 01SEP98, 01OCT98, 02NOV98, 01DEC98, 04JAN99,
01FEB99, 01MAR99, 01APR99, 04MAY99, 01JUN99, 01JUL99, 02AUG99, 01SEP99,
01OCT99, 01NOV99, 01DEC99, 04JAN00, 01FEB00, 01MAR00, 03APR00, 02MAY00,
01JUN00, 03JUL00, 01AUG00, 01SEP00, 02OCT00, 01NOV00, 01DEC00, 02JAN01,
01FEB01, 01MAR01, 02APR01, 01MAY01, 01JUN01, 02JUL01, 01AUG01, 04SEP01,
01OCT01, 01NOV01, 03DEC01, 02JAN02, 01FEB02, 01MAR02, 02APR02, 01MAY02,
03JUN02, 01JUL02, 01AUG02, 03SEP02, 01OCT02, 01NOV02, 02DEC02, 02JAN03,
03FEB03, 03MAR03, 01APR03, 01MAY03, 02JUN03, 01JUL03.


Business Day Convention:  MODIFIED FOLLOWING BANK DAY

Compounding:              INAPPLICABLE

Amortizing:               APPLICABLE

    Amortization Schedule:
                  
                  01MAY98  01JUN98   9,000,000.00
                  01JUN98  01JUL98   9,000,000.00
                  01JUL98  03AUG98   9,000,000.00
                  03AUG98  01SEP98   8,892,857.14
                  01SEP98  01OCT98   8,785,714.28

                                      2
<PAGE>   27
                  01OCT98  02NOV98   8,678,571.42
                  02NOV98  01DEC98   8,571,428.56
                  01DEC98  01JAN99   8,464,285.70
                  04JAN99  01FEB99   8,357,142.84
                  01FEB99  01MAR99   8,249,999.98
                  01MAR99  01APR99   8,142,857.12
                  01APR99  04MAY99   8,035,714.26
                  04MAY99  01JUN99   7,928,571.40
                  01JUN99  01JUL99   7,821,428.54
                  01JUL99  02AUG99   7,714,285.68
                  02AUG99  01SEP99   7,607,142.82
                  01SEP99  01OCT99   7,499,999.96
                  01OCT99  01NOV99   7,392,857.10
                  01NOV99  01DEC99   7,285,714.24
                  01DEC99  04JAN00   7,178,571.38
                  04JAN00  01FEB00   7,071,428.52
                  01FEB00  01MAR00   6,964,285.66
                  01MAR00  03APR00   6,857,142.80
                  03APR00  02MAY00   6,749,999.94
                  02MAY00  01JUN00   6,642,857.08
                  01JUN00  03JUL00   6,535,714.22
                  03JUL00  01AUG00   6,428,571.36
                  01AUG00  01SEP00   6,321,428.50
                  01SEP00  02OCT00   6,214,285.64
                  02OCT00  01NOV00   6,107,142.78
                  01NOV00  01DEC00   5,999,999.92
                  01DEC00  02JAN01   5,892,857.06
                  02JAN01  01FEB01   5,785,714.20
                  01FEB01  01MAR01   5,678,571.34
                  01MAR01  02APR01   5,571,428.48
                  02APR01  01MAY01   5,464,285.62
                  01MAY01  01JUN0l   5,357,142.76
                  01JUN01  02JUL01   5,249,999.90
                  02JUL01  01AUG01   5,142,857.04
                  01AUG01  04SEP01   5,035,714.18
                  04SEP01  01OCT01   4,928,571.32
                  01OCT01  01NOV01   4,821,428.46
                  01NOV01  03DEC01   4,714,285.60
                  03DEC01  02JAN02   4,607,142.74
                  02JAN02  01FEB02   4,499,999.88
                  01FEB02  01MAR02   4,392,857.02
                  01MAR02  02APR02   4,285,714.16
                  02APR02  01MAY02   4,178,571.30
                  01MAY02  03JUN02   4,071,428.44
                  03JUN02  01JUL02   3,964,285.58
                  01JUL02  01AUG02   3,857,142.72
                  01AUGO2  03SEP02   3,749,999.06
                  03SEP02  01OCT02   3,642,857.00
                  01OCT02  01NOV02   3,535,714.14
                  01NOV02  02DEC02   3,428,571.28
                  02DEC02  02JAN03   3,321,428.42
                  02JAN03  03FEB03   3,214,285.56
                  03FEB03  03MAR03   3,107,142.70
                  03MAR03  01APR03   2,999,999.84

                                      3
<PAGE>   28
                  01APR03  01MAY03   2,892,856.98
                  01MAY03  02JUN03   2,785,714.12
                  02JUNO3  01JUL03   2,678,571.26


Business Days For Payments:
NEW YORK
LONDON

Our Instructions
CORESTATES BANK, N.A.
ABA   031000011
A/C#  0132-0313
ATTN: INVESTMENT OPERATIONS


UNITED STATES LIME & MINERALS, INC. Payment Instructions

USLM General Account
ABA   031000011
A/C#  0174-3009


Please confirm that the foregoing correctly sets forth the terms of the 
transaction by signing and returning it to us.


CORESTATES BANK, N.A.
                                    Accepted and confirmed:

By:  \s\ Lisa A. Lunny              By:  \s\ F. Gene Winfield
    ------------------------            ------------------------
Name:   Lisa A. Lunny               Name:  F. Gene Winfield
Title:  Vice President              Title:    Treasurer



Transaction introduced by CoreStates Securities Corp

















                                      4