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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                             ----------------------

                                  SCHEDULE TO
                                 (RULE 14D-100)

            TENDER OFFER STATEMENT UNDER SECTION 14(D)(1) OR 13(E)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
                                (AMENDMENT NO. 6)

                             ----------------------

                             PYR ENERGY CORPORATION

                       (Name of Subject Company (Issuer))

                             ----------------------

                            SAMSON ACQUISITION CORP.
                            SAMSON INVESTMENT COMPANY
                      (Names of Filing Persons (Offerors))

                             ----------------------

                    COMMON STOCK, PAR VALUE $0.001 PER SHARE
                         (Title of Class of Securities)

                                    693677106
                      (CUSIP Number of Class of Securities)

                             ----------------------

                                ANNABEL M. JONES
                  ASSISTANT GENERAL COUNSEL - CORPORATE AFFAIRS
                            SAMSON INVESTMENT COMPANY
                             TWO WEST SECOND STREET
                              TULSA, OKLAHOMA 74103
                                 (918) 591-1006

                                 WITH A COPY TO:

                                 R. SCOTT COHEN
                           WEIL, GOTSHAL & MANGES LLP
                          200 CRESCENT COURT, SUITE 300
                                DALLAS, TX 75201
                 (Name, Address and Telephone Numbers of Person
  Authorized to Receive Notices and Communications on Behalf of Filing Persons)

                             ----------------------

                           CALCULATION OF FILING FEE*
================================   =============================================
        Transaction Valuation                  Amount of Filing Fee**
--------------------------------   ---------------------------------------------
           $48,021,118.60                            $1,474.25
--------------------------------   ---------------------------------------------
*     Estimated for purposes of calculating the amount of the filing fee only.
      Calculated by multiplying $1.30, the per share tender offer price, by the
      sum of (i) the 38,010,258 outstanding shares of common stock, par value
      $0.001 per share, of PYR Energy Corporation as of April 10, 2007
      (according to PYR Energy Corporation's Schedule 14D-9 filed on April 11,
      2007 and the merger agreement attached as Exhibit (d)(1) to amendment no.
      3 to Schedule TO filed on April 24, 2007) less the 3,689,200 shares owned
      by Samson Investment Company, (ii) 1,990,764 shares subject to option
      grants made under the PYR Energy Corporation's share-based compensation
      plans (according to the merger agreement attached as Exhibit (d)(1) to
      amendment no. 3 to Schedule TO filed on April 24, 2007), and (iii) 627,500
      shares under warrants issued to third parties for services performed
      (according to the merger agreement attached as Exhibit (d)(1) to amendment
      no. 3 to Schedule TO filed on April 24, 2007).

**    The amount of the filing fee, calculated in accordance with Regulation
      240.0-11 of the Securities Exchange Act of 1934, as amended, is calculated
      by multiplying the transaction value by 0.0000307.

[X]      Check the box if any part of the fee is offset as provided by Rule
         0-11(a) (2) and identify the filing with which the offsetting fee
         was previously paid. Identify the previous filing by registration
         statement number, or the Form or Schedule and the date of its
         filing.

         Amount Previously Paid:    $92.33         Filing Party:  Samson
                                                                  Investment
                                                                  Company
         Form or Registration No.:  SC TO-T/A      Date Filed:    April 24, 2007



         Amount Previously Paid:    $1,381.92      Filing Party:  Samson
                                                                  Investment
                                                                  Company
         Form or Registration No.:  SC TO-T        Date Filed:    March 28, 2007


[_]   Check the box if the filing relates solely to preliminary communications
      made before the commencement of a tender offer.

      Check the appropriate boxes below to designate any transactions to which
      the statement relates:

      [X]   third-party tender offer subject to Rule 14d-1.
      [_]   issuer tender offer subject to Rule 13e-4.
      [_]   going-private transaction subject to Rule 13e-3.
      [X]   amendment to Schedule 13D under Rule 13d-2.

     Check the following box if the filing is a final amendment reporting the
     results of the tender offer:  [_]

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                                  INTRODUCTION

      This Amendment No. 6 (this "Amendment") amends and supplements the Tender
Offer Statement on Schedule TO filed on March 28, 2007 and amended by Amendment
No. 1 filed April 5, 2007 and amended by Amendment No. 2 on April 11, 2007 and
amended by Amendment No. 3 on April 24, 2007 amended by Amendment No. 4 on April
30, 2007 and amended by Amendment No. 5 on May 25, 2007 (as so amended, the
"Schedule TO") by Samson Acquisition Corp. ("Purchaser"), a Maryland corporation
and wholly owned subsidiary of Samson Investment Company, a Nevada corporation
("Parent"). The Schedule TO relates to the offer by Purchaser to purchase all
outstanding shares of common stock, par value $0.001 per share, of PYR Energy
Corporation, a Maryland corporation (the "Company"), for $1.30 net per share in
cash (subject to applicable withholding taxes), without interest, upon the terms
and subject to the conditions set forth in the Offer to Purchase dated March 28,
2007, as amended (the "Offer to Purchase"). This Amendment is being filed on
behalf of Purchaser and Parent. Except as specifically provided herein, this
Amendment does not modify any of the information previously reported on the
Schedule TO.

ITEM 11. ADDITIONAL INFORMATION.


      On June 4, 2007, Parent and Purchaser announced that they have extended
the expiration of the previously announced subsequent offering period to
Tuesday, June 12, 2007 at 5:00 p.m., New York City time, unless extended. As of
June 4, 2007, and including those shares tendered in the initial offering
period, approximately 27,481,752 shares of the Company's common stock have been
tendered, which, together with the shares owned by Purchaser prior to the
commencement of the Offer, represents approximately 82 percent of the Company's
outstanding common stock. All tendered shares have been accepted for payment.
During the subsequent offering period, Purchaser will continue to accept for
payment and promptly pay for shares of the Company as they are tendered.
Stockholders who tender Shares during such period will be paid the same $1.30
per Share, net to the seller in cash (subject to applicable withholding taxes),
without interest, paid during the initial offering period. The procedures for
accepting the Offer and tendering Shares during the subsequent offering period
are the same as those described for the Offer in the Offer to Purchase and the
Supplement to the Offer to Purchase, except that (i) the guaranteed delivery
procedures may not be used during the subsequent offering period and (ii) Shares
tendered during the subsequent offering period may not be withdrawn. Purchaser
may further extend the subsequent offering period. If the subsequent offering
period is extended, Purchaser will notify Wells Fargo Bank, N.A., the
Depositary, and issue an announcement to that effect prior to 9:00 a.m., New
York City time, on the next business day following the date the subsequent
offering period was scheduled to expire. The press release issued by Parent
announcing the extension of the subsequent offering period is attached hereto as
Exhibit (a)(20).

ITEM 12.   EXHIBITS.

      Item 12 of the Schedule TO is hereby amended and supplemented by the
addition of Exhibit (a)(20) and, as so amended, is restated as follows:

(a)(1)                             Offer to Purchase, dated March 28, 2007

(a)(2)                             Form of Letter of Transmittal

(a)(3)                             Form of Notice of Guaranteed Delivery

(a)(4)                             Form of Letter to Brokers, Dealers,
                                   Commercial Banks, Trust Companies and Other
                                   Nominees

(a)(5)                             Form of Letter to Clients

(a)(6)                             Form of Guidelines for Certification of
                                   Taxpayer Identification Number on Substitute
                                   Form W-9

(a)(7)                             Summary Advertisement as published in The New
                                   York Times on March 28, 2007

(a)(8)                             Press Release announcing the commencement of
                                   the Offer issued by Parent on March 28, 2007


                                       3




(a)(9)                             Press Release announcing Parent's intention
                                   to commence the Offer issued by
                                   Parent on March 20, 2007 (incorporated by
                                   reference to Schedule TO filed by Parent on
                                   March 20, 2007)

(a)(10)                            Letter dated March 20, 2007 from Parent to
                                   the Chief Executive Officer and the Board of
                                   Directors of the Company (included in Exhibit
                                   (a)(9))

(a)(11)                            Press Release, dated April 5,2007, announcing
                                   less than expected drilling results on the
                                   Nome-Harder No. 1 Well

(a)(12)                            Joint Press Release, dated April 11, 2007,
                                   announcing the agreement in principle between
                                   the Company and Purchaser related to the
                                   revised Offer

(a)(13)                            Joint Press Release, dated April 23, 2007,
                                   announcing the entry into a definitive Merger
                                   Agreement and extension of the Offer

(a)(14)                            Supplement dated April 30, 2007 to Offer to
                                   Purchase dated March 28, 2007

(a)(15)                            Form of Revised Letter of Transmittal

(a)(16)                            Form of Revised Notice of Guaranteed Delivery

(a)(17)                            Form of Revised Letter to Brokers, Dealers,
                                   Commercial Banks, Trust Companies and Other
                                   Nominees

(a)(18)                            Form of Revised Letter to Clients

(a)(19)                            Press Release announcing Parent's successful
                                   tender offer for the Shares

(a)(20)                            Press Release, dated June 4, 2007, announcing
                                   Parent's extension of the expiration date for
                                   the subsequent offering period

(d)(1)                             Agreement and Plan of Merger dated as of
                                   April 23, 2007 among Parent, Purchaser and
                                   the Company





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                                    SIGNATURE

      After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

                                        SAMSON ACQUISITION CORP.


                                        By:  /s/  Jack A. Canon
                                            ------------------------------------
                                            Name:  Jack A. Canon
                                            Title: Senior Vice President



                                        SAMSON INVESTMENT COMPANY


                                        By:  /s/  Jack A. Canon
                                            ------------------------------------
                                            Name:  Jack A. Canon
                                            Title: Senior Vice President,
                                                   General Counsel and Secretary


Dated: June 5, 2007






                                  EXHIBIT INDEX

EXHIBIT NO.                        DOCUMENT
-----------                        --------

(a)(1)                             Offer to Purchase, dated March 28, 2007

(a)(2)                             Form of Letter of Transmittal

(a)(3)                             Form of Notice of Guaranteed Delivery

(a)(4)                             Form of Letter to Brokers, Dealers,
                                   Commercial Banks, Trust Companies and Other
                                   Nominees

(a)(5)                             Form of Letter to Clients

(a)(6)                             Form of Guidelines for Certification of
                                   Taxpayer Identification Number on Substitute
                                   Form W-9

(a)(7)                             Summary Advertisement as published in The New
                                   York Times on March 28, 2007

(a)(8)                             Press Release announcing the commencement of
                                   the Offer issued by Parent on March 28, 2007

(a)(9)                             Press Release announcing Parent's intention
                                   to commence the Offer issued by
                                   Parent on March 20, 2007 (incorporated by
                                   reference to Schedule TO filed by Parent on
                                   March 20, 2007)

(a)(10)                            Letter dated March 20, 2007 from Parent to
                                   the Chief Executive Officer and the Board of
                                   Directors of the Company (included in Exhibit
                                   (a)(9))

(a)(11)                            Press Release, dated April 5,2007, announcing
                                   less than expected drilling results on the
                                   Nome-Harder No. 1 Well

(a)(12)                            Joint Press Release, dated April 11, 2007,
                                   announcing the agreement in principle between
                                   the Company and Purchaser related to the
                                   revised Offer

(a)(13)                            Joint Press Release, dated April 23, 2007,
                                   announcing the entry into a definitive Merger
                                   Agreement and extension of the Offer

(a)(14)                            Supplement dated April 30, 2007 to Offer to
                                   Purchase dated March 28, 2007

(a)(15)                            Form of Revised Letter of Transmittal

(a)(16)                            Form of Revised Notice of Guaranteed Delivery

(a)(17)                            Form of Revised Letter to Brokers, Dealers,
                                   Commercial Banks, Trust Companies and Other
                                   Nominees

(a)(18)                            Form of Revised Letter to Clients

(a)(19)                            Press Release announcing Parent's successful
                                   tender offer for the Shares

(a)(20)                            Press Release, dated June 4, 2007, announcing
                                   Parent's extension of the expiration date for
                                   the subsequent offering period*

(d)(1)                             Agreement and Plan of Merger dated as of
                                   April 23, 2007 among Parent, Purchaser and
                                   the Company

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*   Filed herewith.
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