SECOND AMENDING AGREEMENT

                  THIS AGREEMENT made as of the 30th day of January, 2004.

BETWEEN:

                  FRONTEER DEVELOPMENT GROUP INC.,
                  a corporation incorporated under the laws of the
                  Province of Ontario,

                  (hereinafter referred to as the "Optionor")

                  - and -

                  NORTHWESTERN MINERAL VENTURES INC.,
                  a corporation incorporated under the laws of the
                  Province of Ontario,

                  (hereinafter referred to as the "Optionee")


                  WHEREAS the parties hereto entered into an option agreement
made as of the 26th day of September, 2003, as amended by the first amending
agreement made as of the 17th day of December, 2003 (the "Option Agreement");

                  AND WHEREAS the parties wish to further amend the Option
Agreement to provide for partial vesting by the Optionee;

                  NOW THEREFORE THIS AGREEMENT WITNESSETH that in consideration
of the sum of Five Dollars ($5.00) now paid by each of the parties hereto to the
other (the receipt and sufficiency of which is hereby acknowledged), and for
other good and valuable consideration, the parties hereto agree as follows:

1. The schedule of exploration Expenditures in section 4.02 of the Option
Agreement shall be replaced with the following schedule:



                  Date                                                                       Amount
                  ----                                                                       ------
                                                                                          
                  On or before the first anniversary of the Effective Date                        $500,000
                  On or before the second anniversary of the Effective Date                       $500,000
                  On or before the third anniversary of the Effective Date                      $1,000,000
                  On or before the fourth anniversary of the Effective Date                     $1,000,000
                  On or before the fifth anniversary of the Effective Date                      $2,000,000



                                       2

2. The Option Agreement shall be further amended to provide that if the Optionee
makes the Cash Payments required in section 4.03 and incurs the Expenditures set
out below, it shall be deemed to have acquired and be vested with an undivided
right, title and interest in the Property free and clear of all liens, charges,
encumbrances, security interests and adverse claims and except for proportionate
responsibility for the Underlying Royalty, in the percentage so indicated
herein:

         (a)      incurs aggregate Expenditures of not less than $1,000,000 on
                  or before the second anniversary of the Effective Date - 10%;

         (b)      incurs aggregate Expenditures of not less than $3,000,000 on
                  or before the fourth anniversary of the Effective Date - 30%;
                  and

         (c)      incurs aggregate expenditures of not less than $5,000,000 on
                  or before the fifth anniversary of the Effective Date - 50%.

3. At such time as the Optionee shall have earned a vested interest and shall
notify the Optionor that it does not wish to earn any additional interest in the
Property, or the Optionee's vested interest shall have been otherwise clearly
determinable, the parties hereto shall enter into the joint venture agreement
attached hereto as Schedule "A" (the "Joint Venture Agreement") and shall
complete sections 4.02 and 4.03 thereof to reflect the expenditures and
interests of the parties. The Optionee's Initial Contribution in section 4.02 of
the Joint Venture Agreement shall be the Optionee's Expenditures under the
Option Agreement. The Optionor's Initial Contribution will be determined, based
upon the percentage level at which the Optionee vests. If the Optionee vests at
50%, the Optionor's Initial Contribution shall be deemed to be equal to the
Optionee's. If the Optionee vests at 10%, the Optionor's Initial Contribution
shall be deemed to be 9 times the Optionee's Initial Contribution, and if the
Optionee vests at 30%, the Optionor's Initial Contribution shall be deemed to be
2.33 times the Optionee's Initial Contribution.

4. In all other respects, the Option Agreement is hereby ratified and confirmed.

5. This agreement may be executed in one or more counterparts, each of which so
executed shall constitute an original and all of which together shall constitute
one and the same agreement.



                                       3

         IN WITNESS WHEREOF the parties hereto have executed this Agreement as
of the date first above written.

                                      FRONTEER DEVELOPMENT GROUP INC.


                                      By:            "Mark O'Dea"
                                               ---------------------------------

                                      NORTHWESTERN MINERAL VENTURES INC.


                                      By:             "Kabir Ahmed"
                                               ---------------------------------