FIRST AMENDMENT OF THIRD AMENDED AND RESTATED CREDIT AGREEMENT

Exhibit 10.8

FIRST AMENDMENT OF

THIRD AMENDED AND RESTATED CREDIT AGREEMENT

THIS FIRST AMENDMENT OF THIRD AMENDED AND RESTATED CREDIT AGREEMENT (this “Amendment”), dated as of May 23, 2007, is by and among INTREPID MINING LLC, a Colorado limited liability company (“IMLLC”), INTREPID POTASH-MOAB, LLC, a Delaware limited liability company (“IPMLLC”), INTREPID POTASH-NEW MEXICO, LLC, a New Mexico limited liability company (“IPNMLLC”), INTREPID POTASH-WENDOVER, LLC, a Colorado limited liability company (“IPWLLC”), U.S. BANK NATIONAL ASSOCIATION, a national banking association (“USB”), in its capacity as lead arranger and Agent (“Agent”), and the Lender referred to below.

RECITALS

A. IMLLC, IPMLLC, IPNMLLC and IPWLLC (“Borrowers”), Agent and USB, in its capacity as the sole lender thereunder (“Lender”), are parties to a Third Amended and Restated Credit Agreement dated as of March 9, 2007 (the “Credit Agreement”).

B. Borrowers, Agent and Lender desire that this Amendment be executed and delivered in order to amend certain terms and provisions of the Credit Agreement.

AMENDMENT

NOW, THEREFORE, in consideration of $10.00 and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereby agree as follows:

“Aggregate Lenders’ Commitment (Revolving)” means, at any time, the sum of the Commitments (Revolving) of all Lenders at that time; provided that, upon the request of Borrowers, unless Agent is aware, either at the time of such request or at any time prior to its implementation, of the occurrence and continuation of an uncured Event of Default, Agent may agree to increase said amount to a maximum of $125,000,000, so long as Agent is able to obtain sufficient additional Commitments (Revolving) from Lenders (including then-existing Lenders and third parties willing to become Lenders hereunder) to fund any such increase.

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“Commitment (Revolving)” means, at any time, for any Lender: (a) such Lender’s Initial Commitment (Revolving), plus (b) any portion of any other Lender’s Initial Commitment (Revolving) that has been assigned to such Lender pursuant to Section 10.3 below, plus (c) the portion, if any, of any and all increases in the Aggregate Lenders’ Commitment (Revolving) that such Lender has agreed to fund, minus (d) any portion of such Lender’s Initial Commitment (Revolving) that it has assigned to any other Lender pursuant to Section 10.3 below, minus (e) any reduction in such Lender’s Commitment (Revolving) pursuant to Section 2.6 below.

“Guarantor Subsidiary” means either of the Initial Guarantors or any other Subsidiary that has been requested to execute a Guaranty and/or any Security Document as provided in Section 6.2(p) below.

(b) 50 percent of the net cash proceeds received by any Borrower upon the issuance of any subordinated debt or equity securities (excluding the proceeds of the sale of approximately 20 percent of the equity in IMLLC to Platte River Ventures or an affiliate thereof for approximately $39,000,000 on or before August 31, 2007), except to the extent that such net cash proceeds are used for the Solution Mining Project.

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EXECUTED as of the date first above written.

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SCHEDULE I

LENDERS’ COMMITMENTS AND OTHER LENDER/AGENT DATA

A. INITIAL LENDER AND COMMITMENTS AS OF MARCH 9, 2007:

B. LENDERS AND COMMITMENTS AS OF MAY 31, 2007:

Schedule I-1

Schedule I-2

Schedule I-3

C. AGENT INFORMATION:

Agent’s Address:

Schedule I-4