Exhibit 10-6

NOTE MODIFICATION AGREEMENT

Borrower: The Goldfield Corporation

Address: 1684 W. Hibiscus Blvd., Melbourne, Florida, 32901

Customer Number: 9660933082

Note Number: 00002

Original Amount of Note: $1,000,000.00

Original date: 08/26/2005

Modification Amount: $3,000,000.00

Modification Date: 2/22/2011

This Note Modification Agreement (hereinafter Agreement) is made and entered into this 22^nd day of February, 2011, by and between The Goldfield Corporation, maker(s), co-maker(s), endorser(s), or other obligor(s) on the Promissory Note (as defined below), hereinafter also referred to jointly and severally as Borrower(s); Branch Banking and Trust Company, a North Carolina banking corporation, hereinafter referred to as Bank.

Witnesseth: Whereas, Borrower(s) has previously executed a Promissory Note payable to Bank, which Promissory Note includes the original Promissory Note and all renewals, extensions and modifications thereof, collectively “Promissory Note”, said Promissory Note being more particularly identified by description of the original note above; and Borrower(s) and Bank agree that said Promissory Note be modified only to the limited extent as is hereinafter set forth; that all other terms, conditions, and covenants of said Promissory Note remain in full force and effect, and that all other obligations and covenants of Borrower(s), except as herein modified, shall remain in full force and effect, and binding between Borrower(s) and Bank; and Whereas Debtor(s)/Mortgagor(s), if different from Borrower(s), has agreed to the terms of this modification; NOW THEREFORE, in mutual consideration of the premises, the sum of Ten Dollars ($10) and other good and valuable consideration, each to the other parties paid , the parties hereto agree that said Promissory Note is amended as hereinafter described:

INTEREST RATE, PRINCIPAL AND INTEREST PAYMENT TERM MODIFICATIONS (To the extent no change is made, existing terms continue. Sections not completed are deleted.)

Interest shall accrue from the date hereof on the unpaid principal balance outstanding from time to time at the:

Adjusted LIBOR rate, as defined in the attached Addendum to Note Modification Agreement.

Principal and Interest are payable as follows:

Principal Plus accrued interest is due in full at maturity on January 5, 2012.

Accrued interest is payable monthly, commencing on March 5, 2011 and continuing on the same day of each calendar period thereafter through and including the payment due December 5, 2011, with one final payment of all remaining interest due on January 5, 2012.

Prior to an event of default, Borrower may borrow, repay, and reborrow pursuant to the terms of the Loan Agreement dated February 22, 2011, between Borrower and Bank.

No documentary stamp tax is required to be paid on this Agreement as such tax was previously paid on the Promissory Note which this Agreement modifies and extends and which is not increased by this Agreement or on the Mortgage, if any, securing the Promissory Note.

The Borrower(s) promises to pay Bank, or order, a late fee in the amount of five percent (5%) of any installment past due for ten (10) or more days. Where any installment payment is past due for ten (10) or more days, subsequent payments shall first be applied to the past due balance. In addition, the undersigned shall pay to Bank a returned payment fee if the undersigned or any other obligor hereon makes any payment at any time by check or other instrument, or by any electronic means, which is returned to Bank because of nonpayment due to nonsufficient funds.

COLLATERAL: The Promissory Note, as modified, and the performance of the terms of any agreement or instrument relating to, evidencing, or securing the Promissory Note, as modified, shall be additionally secured by collateral hereinafter described, a new security instrument shall be executed by Borrower(s), and/or Debtor(s) /Grantor(s), and all other steps necessary to perfect or record the Bank’s lien with priority acceptable to Bank shall be taken.

Security Agreement granting a security interest to Bank dated February 22, 2011 given by Southeast Power Corporation.

Loan Agreement dated February 22, 2011, executed by Borrower and Guarantors.

If the Promissory Note being modified by this Agreement is signed by more than one person or entity, the modified Promissory Note shall be the joint and several obligation of all signers and the property and liability of each and all of them. It is expressly understood and agreed that this Agreement is a modification only and not a novation. The original obligation of the Borrower(s) as evidenced by the Promissory Note above described is not extinguished hereby. It is also understood and agreed that except for the modification(s) contained herein said Promissory Note, and any other Loan Documents or Agreements evidencing, securing or relating to the Promissory Note and all singular terms and conditions thereof, shall be and remain in full force and effect, This Agreement shall not release or affect the liability of any co-makers, obligors, endorsers or guarantors of said Promissory Note. Borrower and Debtor(s)/Mortgagor(s), if any, jointly and severally consent to the terms of this Agreement, waive any objection thereto, affirm any and all obligations to Bank and certify that there are no defenses or offsets against said obligations or the Bank, including without limitation the Promissory Note. Bank expressly reserves all rights as to any party with right of recourse on the aforesaid Promissory Note.

In the event periodic accruals of interest shall exceed any periodic fixed payment amount described above, the fixed payment amount shall be immediately increased or supplemental interest payments required on the same periodic basis as specified above (increased fixed payments or supplemental payments to be determined in the Bank’s sole discretion), in such amounts and at such times as shall be necessary to pay all accruals of interest for the period and all accruals of unpaid interest from previous periods. Such adjustments to the fixed payment amount or supplemental payments shall remain in effect for so long as any interest accruals shall exceed the original fixed payment amount and shall be further adjusted upward or downward to reflect changes in any variable interest rate based on an index such as the Bank’s Prime Rate; provided that unless elected otherwise above, the fixed payment amount shall not be reduced below the original fixed payment amount. However, Bank shall have the right, in its sole discretion, to lower the fixed payment amount below the original payment amount. Notwithstanding any other provision contained in this agreement, in no event shall the provisions of this paragraph be applicable to any Promissory Note which requires disclosures pursuant to the Consumer Protection Act (Trust-in-Lending Act), 15§ 1601, et seq., as implemented by Regulation Z. Borrower agrees that the only interest charge is the interest actually stated in this Note, and that any loan or origination fee shall be deemed

charges rather than interest, which charges are fully earned and non-refundable. It is further agreed that any late charges are not a charge for the use of money but are imposed to compensate Bank for some of the administrative services, costs and losses associated with any delinquency or default under this Note, and said charges shall be fully earned and non-refundable when accrued. All other charges imposed by Bank upon Borrower in connection with this Note and the loan including, without limitation, any commitment fees, loan fees, facility fees, origination fees, discount points, default and late charges, prepayment fees, statutory attorneys’ fees and reimbursements for costs and expenses paid by Bank to third parties or for damages incurred by Bank are and shall be deemed to be charges made to compensate Bank for underwriting and administrative services and costs, other services, and costs or losses incurred and to be incurred by Bank in connection with this Note and the loan and shall under no circumstances be deemed to be charges for the use of money. All such charges shall be fully earned and non-refundable when due. The Bank may, at its option, charge any fees for the modification, renewal, extension, or amendment of any of the terms of the Promissory Note(s) permitted by Florida law.

In the words “Prime Rate”, “Bank Prime Rate”, “BB&T Prime Rate”, “Bank’s Prime Rate” or “BB&T’s Prime Rate” are used in this Agreement, they shall refer to the rate announced by the Bank from time to time as its Prime Rate. The Bank makes loans both above and below the Prime Rate and uses indexes other than the Prime Rate. Prime Rate is/the name given a rate index used by the Bank and does not in itself constitute a representation of any preferred rate or treatment.

Unless otherwise provided herein, it is expressly understood and agreed by and between Borrower(s), Debtor (s) /Mortgagor(s) and Bank that any and all collateral (including but not limited to real property, personal property, fixtures, inventory, accounts, instruments, general intangibles, documents, chattel paper, and equipment) given as security to insure faithful performance by Borrower(s) and any other third party of any and all obligations to Bank, however created, whether now existing or hereafter arising, shall remain as security for the Promissory Note as modified hereby.

It is understood and agreed that if Bank has released collateral herein, it shall not be required or obligated to take any further steps to release said collateral from any lien or security interest unless Bank determines, in its sole discretion, that it may do so without consequence to its secured position and relative priority in other collateral; and unless Borrower(s) bears the reasonable cost of such action. No delay or omission on the part of the Bank in exercising any right hereunder shall operate as a waiver of such right or of any other right of the Bank, nor shall any delay, omission or waiver on any one occasion be deemed a bar to or waiver of the same, or of any other right on any further occasion. Each of the parties signing this Agreement regardless of the time, order or place of signing waives presentment, demand, protest, and notices of every kind, and assents to any one or more extensions or postponements of the time of payment or any other indulgences, to any substitutions, exchanges or releases of collateral if at any time there is available to the Bank collateral for the Promissory Note, as amended, and to the additions or releases of any other parties or persons primarily or secondarily liable. Whenever possible the provisions of this Agreement shall be interpreted in such manner as to be effective and valid under applicable law, but if any provision of this Agreement prohibited by or invalid under such law, such provisions shall be ineffective to the extent of any such prohibition or invalidity, without invalidating the remainder of such provision or the remaining provisions of this Agreement. All rights and obligations arising hereunder shall be governed by and construed in accordance with the laws of the same state which governs the interpretation and enforcement of the Promissory Note.

From and after any event of default under this Agreement, the Promissory Note, or any related mortgage, security agreement or loan agreement, interest shall accrue on the sum of the principal balance and accrued interest then outstanding at the variable rate equal to the Bank’s Prime Rate plus 5% per annum (“Default Rate”), provided that such rate shall not exceed at any time the highest rate of interest permitted by the laws of the State of Florida; and further that such rate shall apply after judgement. In the event of any default, the then remaining unpaid principal amount and accrued but unpaid interest then outstanding shall bear interest at the Default Rate until such principal and interest have been paid in full. Bank shall not be obligated to accept any check, money order, or other payment instrument marked “payment in full” on any disputed amount due hereunder, and Bank expressly reserves the right to reject all such payment instruments. Borrower agrees that tender of its check or other payment instrument so marked will not satisfy or discharge its obligation under this Note, disputed or otherwise, even if such check or payment instrument is inadvertently processed by Bank unless in fact such payment is in fact sufficient to pay the amount due hereunder.

WAIVER OF TRIAL BY JURY. UNLESS EXPRESSLY PROHIBITED BY APPLICABLE LAW, THE UNDERSIGNED HEREBY WAIVE THE RIGHT TO TRIAL BY JURY OF ANY MATTERS OR CLAIMS ARISING OUT OF THIS AGREEMENT, THE PROMISSORY NOTE OR ANY LOAN DOCUMENT EXECUTED IN CONNECTION HEREWITH OR OUT OF THE CONDUCT OF THE RELATIONSHIP BETWEEN THE UNDERSIGNED AND BANK. THIS PROVISION IS A MATERIAL INDUCEMENT FOR BANK TO MAKE THE LOAN EVIDENCED BY THE PROMISSORY NOTE AND THIS AGREEMENT. FURTHER, THE UNDERSIGNED HEREBY CERTIFY THAT NO REPRESENTATIVE OR AGENT OF BANK, NOR BANK’S COUNSEL, HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT BANK WOULD NOT SEEK TO ENFORCE THIS WAIVER OR RIGHT TO JURY TRIAL PROVISION IN THE EVENT OF LITIGATION. NO REPRESENTATIVE OR AGENT OF BANK, NOR BANK’S COUNSEL, HAS THE AUTHORITY TO WAIVE, CONDITION OR MODIFY THIS PROVISION,

Unless otherwise required under a Loan Agreement, if applicable, and as long as any indebtedness evidenced by this Promissory Note, as modified by this Agreement remains outstanding or as long as Bank remains obligated to make advances, the undersigned shall furnish annually an updated financial statement in a form satisfactory to Bank, which, when delivered shall be the property of the Bank. Further, the undersigned agree to provide any and all documentation requested by the Bank in order to verify the identity of the undersigned in accordance with the USA Patriot Act.

(SIGNATURES ON FOLLOWING PAGE)

NOTE MODIFICATION SIGNATURE PAGE

Borrower: The Goldfield Corporation

Account Number: 9660933082

Modification Amount: $3,000,000.00

Note Number: 00002

Modification Date: 2/22/2011

Notice of Right to Copy of Appraisal: If a 1-4 family residential dwelling is pledged as collateral for this Agreement, you, the undersigned, have a right to copy of the real estate appraisal report used in connection with your application Tor credit. You must forward your request to the Bank no later than 90 days after the date of this Agreement. In your request letter, please provide your name, mailing address, appraised property address, the date of this Agreement, and the account and note numbers shown on the front of this Agreement.

IN WITNESS WHEREOF, THE UNDERSIGNED, on the day and year first written above, has caused this instrument to be executed under seal.