FIRST AMENDMENT TO NOTE PURCHASE AGREEMENTS

Exhibit 4.2

First Amendment

Dated as of July 18, 2005

to

Note Purchase Agreements dated as of June 19, 2003

Re:

5.55% Senior Notes, Series A, due June 19, 2023

4.91% Senior Notes, Series B, due June 19, 2018

5.55% Senior Notes, Series C, due June 19, 2013

Table of Contents

(Not a part of this First Amendment)

Schedule I — Name of Holders and Principal Amount of 2003 Notes

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Dated as of
July 18, 2005

To each of the holders
listed in Schedule I to
this First Amendment

Ladies and Gentlemen:

     Reference is made to (i) the separate Note Purchase Agreements each dated as of June 19, 2003 (the “Note Agreements” ), by and between NRP (Operating) LLC, a Delaware limited liability company (the “Company” ), and each of you, respectively, (ii) the $60,000,000 aggregate principal amount of 5.55% Senior Notes, Series A, due June 19, 2023 of the Company (the “Series A Notes” ), (iii) the $80,000,000 aggregate principal amount of 4.91% Senior Notes, Series B, due June 19, 2018 of the Company (the “Series B Notes” ) and (iv) the $35,000,000 aggregate principal amount of 5.55% Senior Notes, Series C, due June 19, 2013 of the Company (the “Series C Notes,” and collectively with the Series A and Series B Notes, the “2003 Notes” ). Capitalized terms used in this First Amendment (this “First Amendment” ) without definition shall have the meanings given such terms in the Note Agreements.

     For good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Company requests the amendment of certain provisions of the Note Agreements as hereinafter provided.

     Concurrently with the Effective Date, this First Amendment shall be effective, but only in the respects hereinafter set forth:

Section 1. Amendments to Note Agreements .

      Section 1.1. Section 7.1(a) of the Note Agreements is hereby amended as of the Effective Date by inserting the following at the end thereof:

“ provided, however, that, notwithstanding the foregoing, so long as the Company shall be a direct wholly-owned Subsidiary of the Parent and the Parent does not own any assets other than its membership interest in the Company, the Company may deliver the foregoing items as specified in this Section 7.1(a) with respect to the Parent, rather than the Company; provided, further, however, in the event the Company has delivered items required by this Section 7.1(a) with respect to the Parent and the Securities Valuation Office of the National Association of Insurance Commissioners requests additional information (including, without limitation, the financial statements of the Company required to be delivered by the Company pursuant to this Section 7.1(a)) in order to assign or maintain a

designation of the Notes, the Company agrees to timely furnish such information;”

      Section 1.2. Section 7.1(b) of the Note Agreements is hereby amended as of the Effective Date by inserting the following phrase at the end thereof:

“ provided, however, that, notwithstanding the foregoing, so long as the Company shall be a direct wholly-owned Subsidiary of the Parent and the Parent does not own any assets other than its membership interest in the Company, the Company may deliver the foregoing items as specified in this Section 7.1(b) with respect to the Parent, rather than the Company; provided, further, however, in the event the Company has delivered items required by this Section 7.1(b) with respect to the Parent and the Securities Valuation Office of the National Association of Insurance Commissioners requests additional information (including, without limitation, the financial statements of the Company required to be delivered by the Company pursuant to this Section 7.1(b)) in order to assign or maintain a designation of the Notes, the Company agrees to timely furnish such information;”

      Section 1.3. Section 8.3(h)(iii) of the Note Agreements is hereby amended as of the Effective Date by deleting the name “Arch Coal, Inc.” appearing therein and substituting the name “NRP Investment L.P.” therefor.

      Section 1.4. Section 10.6(a)(iii) of the Note Agreements is hereby amended as of the Effective Date by deleting the word “to” appearing in the last line thereof and substituting the phrase “would not” therefor.

      Section 1.5. The new definition “NRP Investment L.P.” is hereby added as of the Effective Date to Schedule B to the Note Agreements in alphabetical order to read as follows:

           “NRP Investment L.P.” means NRP Investment L.P., a Delaware limited partnership.

      Section 1.6. The definition of “Financing Agreement” and “Financing Agreements” set forth on Schedule B to the Note Agreements is hereby amended as of the Effective Date by deleting the phrase “as amended or modified from time to time” appearing therein and substituting the phrase “as amended, modified or supplemented from time to time” therefor.

      Section 1.7. The definition of “Priority Debt” set forth on Schedule B to the Note Agreements is hereby amended as of the Effective Date by deleting the phrase “(other than to the Company or another Subsidiary)” appearing in clause (ii) thereof and substituting the phrase “(other than (a) Debt of a Subsidiary to the Company or another Subsidiary, (b) Debt of a Subsidiary Guarantor pursuant to the Subsidiary Guarantee and (c) Debt of a Subsidiary Guarantor pursuant to the unsecured Guaranty of the obligations of the Company under the Bank Agreement)” therefor.

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      Section 1.8. The definition of “this Agreement” set forth on Schedule B to the Note Agreements is hereby amended as of the Effective Date by deleting the phrase “as amended or modified from time to time” appearing therein and substituting the phrase “as amended, modified or supplemented from time to time” therefor.

Section 2. Limited Waiver.

     With effect from the Effective Date, and subject to the satisfaction of the conditions precedent set forth in Section 3 hereof, the undersigned holders of the 2003 Notes agree and consent that any Default or Event of Default that has occurred prior to the Effective Date pursuant to (i) Section 11(d) of the Note Agreements, solely as a result of the delivery of quarterly or annual financial statements of the Parent, that otherwise meet the requirements of Sections 7.1(a) and (b) of the Note Agreements, in lieu of the quarterly or annual financial statements of the Company required to be delivered pursuant to Sections 7.1(a) and (b) of the Note Agreements or (ii) Section 11(c) of the Note Agreements, solely as a result of the failure to deliver notice of any Default or Event of Default described in clause (i) of this sentence, is hereby waived. This waiver is limited to the specific Defaults or Events of Default described above in this Section 2 and does not extend to (x) any Default or Event of Default occurring after the Effective Date, whether or not similar in nature to the Defaults or Events of Default described above in this Section 2 or (y) any Default or Event of Default existing on or occurring prior to the Effective Date, other than the specific Defaults or Events of Default described above in this Section 2.

Section 3. Conditions Precedent.

     This First Amendment shall not become effective until, and shall become effective on, the Business Day (the “ Effective Date ”) when each of the following conditions shall have been