EXHIBIT 4.12

                  Letter Agreement, dated March 17, 2005, among

                         Baradero Resources Limited, the
                         shareholders of 0724000 BC Ltd.
           (formerly Magellan Gold Corp. and Centrasia Mining Corp.),
                               and 0724000 BC Ltd.








<PAGE>





                             BARADERO RESOURCES LTD.
                          1305 - 1090 WEST GEORGIA ST.
                              VANCOUVER, BC V6E 3V7

March 17, 2005

TO:               Magellan Gold Corp.
                  880 - 609 Granville St.
                  P.O. Box 10321 Pacific Centre
                  Vancouver, BC V7Y 1G5

                  Attention:        Doug Turnbull,
                                    President

AND TO:           The Shareholders of Magellan Gold Corp.


Dear Sirs:

RE:      ACQUISITION OF MAGELLAN GOLD CORP.  ("MAGELLAN") BY BARADERO  RESOURCES
         LTD. ("PUBCO")

We are advised that Magellan is a private  Nevada  company that,  pursuant to an
agreement  with  Marsa Gold  Corp.,  a Kyrgyz  limited  liability  company,  and
Bulakashu Mining Company LLC ("BMC"), a Kyrgyz limited liability company,  dated
September  24, 2004 as amended by an amending  agreement  dated January 18, 2005
(the "BMC Agreement"), has an option to acquire from Marsa Gold Corp. all of the
issued  shares of BMC.  BMC is the  registered  owner of a  certain  exploration
license in respect of lands located in the Kyrgyz Republic, as more particularly
described  in  Schedule  "A"  hereto  (the  "Bulakashu  Property").  In order to
exercise  the  option,  the  following  payments  of shares,  cash and  property
expenditures must be made:

--------------------------------------------------------------------------------
                       BY          BY            BY           BY           BY
                    JAN 2/05    JULY 1/05     JAN 2/06     JAN 2/07     JAN 2/08
--------------------------------------------------------------------------------

CASH               US$40,000    US$40,000    US$40,000            -            -
(total:               (paid)
US$120,000)

SHARES               200,000(1)         -      200,000      250,000      375,000
(total:
1,025,000
shares)

--------------------------------------------------------------------------------
CALENDAR YEAR           2004(2)      2005         2006         2007         2008
--------------------------------------------------------------------------------

MINIMUM           US$110,000   US$350,000   US$500,000   US$650,000   US$750,000
EXPLORATION      (completed)
EXPENDITURES
(total:
US$2,360,000)
--------------------------------------------------------------------------------

1    These  shares  have not yet been  issued at the  request  of the  corporate
     vendor pending the completion of a re-organization of BMC.
2    The 2004 work  program  was  funded by way of a loan to BMC from  Magellan,
     which will be repaid by the issuance of shares of BMC in due course.


<PAGE>
                                      -2-


There are issued and outstanding in Magellan  3,700,100 common shares which were
issued for US$0.005 each (the "Magellan  Shares") and a list of the shareholders
of Magellan is attached hereto as Schedule "B". Apart from the 1,025,000  common
shares to be issued to acquire the BMC Property,  there are no other  securities
issued or issuable in Magellan.  Magellan  currently  has loans  outstanding  to
borrow an aggregate Cdn$200,992.50 and US$145,000.00  (approximately Cdn$382,000
altogether),  which bear interest at 10% per annum from the  respective  date of
advance.  In addition,  Magellan has current  trade  liabilities  of  Cdn$50,000
approximately.  Doug Turnbull  represents that he has the authority of the other
Magellan shareholders to bind them to this letter agreement.

The only securities  issued and outstanding in Pubco are 1,986,521 common shares
and  incentive  stock  options to purchase up to 115,000  common shares at $0.19
each on or before November 26, 2007 (the "Old Stock Options").

It is agreed that Pubco shall acquire from the  shareholders  of Magellan all of
the  issued  shares  of  Magellan  on and  subject  to the  following  terms and
conditions:

Acquiring Entity:           Pubco, a company continued under the laws of British
                            Columbia,  a reporting  issuer in the  Provinces  of
                            British Columbia and Alberta and registered with the
                            U.S. Securities and Exchange Commission as a foreign
                            private  issuer  under the  Securities  Act of 1934,
                            whose  common  shares  are  listed  and  posted  for
                            trading on the TSX  Venture  Exchange  in Canada and
                            trade on the OTCBB in the United States;

Acquired Entity:            Magellan,  a company  incorporated under the laws of
                            Nevada. It is intended to reorganize  Magellan prior
                            to entering into the formal  agreement  below,  such
                            that  it  or  its  assets   will  be  subject  to  a
                            jurisdiction outside of the United States;

Transaction Structure:      The  transaction  will  be  effected  by  way  of an
                            acquisition  by  Pubco  of all  of  the  outstanding
                            shares of Magellan (the "Transaction");

Consideration:              Pubco  shall  issue  in  exchange  for  each  issued
                            Magellan   Share  one  common   share  of  Pubco  as
                            presently constituted. It is acknowledged that these
                            shares shall be subject to a Surplus Security Escrow
                            Agreement  under  the  policies  of the TSX  Venture
                            Exchange and resale rules imposed by the TSX Venture
                            Exchange and securities commissions;


<PAGE>
                                      -3-


Due Diligence Period:       Each of Magellan  and Pubco will have an  unfettered
                            right to conduct and complete  legal,  audit and tax
                            due  diligence  investigations  regarding  the other
                            company  within  30 days of the  acceptance  of this
                            letter  agreement.  On or before  such date,  either
                            Pubco  or  Magellan  may  elect  not to close if the
                            results of its due  diligence  investigation  of the
                            other  company are not  satisfactory  to it,  acting
                            reasonably.

Bridge Financing:           Pubco   acknowledges  that  certain  investors  have
                            provided  financing  to Magellan in order to finance
                            the  operations  of Magellan,  and will  continue to
                            provide additional financing between the date hereof
                            and the  closing  of the  transactions  contemplated
                            hereby (the "Closing"). These funds were advanced to
                            Magellan  by way of loan and the  aggregate  amounts
                            advanced  as of the  date  hereof  is  approximately
                            Cdn$382,000.  These  loans bear  interest at 10% per
                            annum from the respective  date of advance Pubco and
                            Magellan  agree  that  at  Closing,   all  principal
                            amounts  advanced  will be  automatically  converted
                            into  securities  of Pubco  having the same terms as
                            the  securities  issued by Pubco  under the  Private
                            Placement  referred  to below,  which will result in
                            the  issuance  of  2,000,000  units   approximately.
                            Interest  on the  amounts  advanced  will be paid in
                            cash at Closing.

Financing:                  Pubco will use  commercially  reasonable  efforts to
                            complete  a  non-brokered   private  placement  (the
                            "Private  Placement") of 4,000,000  units at a price
                            of  not  less  than  C$0.20  per  unit,   each  unit
                            consisting  of one  common  share of  Pubco  and one
                            warrant  to buy one  common  share for $0.40 for two
                            years from Closing. The number of units to be issued
                            pursuant to the Private Placement shall be increased
                            only if agreed  upon by both  companies.  Subject to
                            the  right of the  existing  management  of Pubco to
                            place  500,000 of the  units,  the  approval  of the
                            placees and the  allocation  of units to the placees
                            shall be as  determined by the New Board (as defined
                            below). The estimated use of proceeds of the Private
                            Placement is as follows:


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                                      -4-


                            ----------------------------------------------------
                            Gross Proceeds of Private Placement         $800,000
                            ----------------------------------------------------
                            TO BE USED AS FOLLOWS:
                            ----------------------------------------------------

                            Minimum required work program for 2005      $200,000
                            G&A for 12 months                           $120,000
                            Property Payments Due
                                 in next 12 months (US$80,000)          $100,000
                            Payment of interest on bridge financing      $20,000
                            Cost of RTO                                 $150,000
                            Unallocated working capital                 $210,000
                            ----------------------------------------------------
                            Total:                                      $800,000
                            ----------------------------------------------------

Conditions to
Closing of Transaction:     (i)    Pubco  shall  have   completed   the  Private
                                   Placement;


                            (ii)   The Board of  directors  of Pubco at  Closing
                                   shall  be  made up of the  following  persons
                                   (the  "New   Board"):   Nick   DeMare,   Doug
                                   Turnbull,  Greg Crowe, Lindsay Bottomer, Cary
                                   Pinkowski,   Oleg   Kim   (subject   to   his
                                   acceptance of the position);

                            (iii)  On or prior to Closing,  Pubco  shall  change
                                   its name to "Magellan Gold Corp.",  "Magellan
                                   Resources  Corp.",  or such other name as may
                                   be acceptable to all  regulatory  authorities
                                   and   approved  by  the  new  Board  and  the
                                   shareholders of Pubco;

                            (iv)   The BMC Agreement shall be amended to provide
                                   that:

                                   a.   all shares to be issued thereunder shall
                                        be issued by Pubco  (including the first
                                        200,000 shares, which will now be issued
                                        at the Closing of the  Transaction)  and
                                        not Magellan; and

                                   b.   the  minimum  exploration   expenditures
                                        required to be incurred in 2005 shall be
                                        reduced to Cdn$200,000,  and the minimum
                                        exploration  expenditures required to be
                                        incurred  in 2006 will be  increased  to
                                        US$690,000;

                            (v)    No  material   adverse   change   shall  have
                                   occurred   in   the   business,   operations,
                                   capital,  financial condition or prospects of
                                   either Magellan or Pubco;

                            (vi)   Prior  to  Closing,  the  parties  will  have
                                   entered  into a formal  agreement  to replace
                                   this  letter   agreement  that  provides  the
                                   mutual representations, warranties, covenants
                                   and closing  deliveries,  including,  without
                                   limitation,    appropriate    corporate   and
                                   securities  opinions  from  counsel  for each
                                   party,  in a  form  that  is  reasonable  and
                                   customary  for  a  transaction   such  as  is
                                   contemplated herein;


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                                      -5-



                            (vii)  Magellan   will  deliver  to  Pubco  a  title
                                   opinion  and  a  43-101  report  on  the  BMC
                                   Property, and audited financial statements of
                                   both  Magellan and BMC, in form and substance
                                   satisfactory to Pubco acting reasonably.  The
                                   43-101  report,  title  opinion  and  audited
                                   financial  statements  shall be  delivered by
                                   April 15, 2005;

                            (viii) Chase  Management  Ltd.  will be  engaged  to
                                   continue      to     provide      accounting,
                                   administration  and  management  services  to
                                   Pubco subsequent to Closing;

                            (ix)   Receipt of the  approval of the  shareholders
                                   of Pubco and of the TSX  Venture  Exchange to
                                   the Transaction and all related matters; and

                            (x)    Closing  of  the   Transaction   and  Private
                                   Placement   occurring  by  June  6,  2005  or
                                   earlier.


Stock Options:              It is  intended  that  Pubco  will adopt a new stock
                            option plan allowing  incentive  stock options to be
                            granted up to 20% of the issued share capital of the
                            Company  at  Closing   (subject  to   adjustment  in
                            accordance  with  the  policies  of the TSX  Venture
                            Exchange), and that under the new plan stock options
                            will be  granted  by Pubco in  conjunction  with the
                            Transaction.   The  New  Board  will  determine  the
                            allotment  of such  stock  options.  The  Old  Stock
                            Options will expire in the  ordinary  course 90 days
                            after Closing in accordance  with the  provisions of
                            Pubco's current Stock Option Plan;

Finder's Fee:               The parties  acknowledge that a finder's fee will be
                            payable at Closing in respect of the  Transaction to
                            Mr. Shapur Salem of  Vancouver,  BC equal to 233,338
                            Pubco shares;

Timing:                     The parties  hereto  agree that they are prepared to
                            make  every   reasonable   effort  to  complete  the
                            Transaction  and Private  Placement as planned.  The
                            parties   will  work  in  good  faith   seeking  all
                            necessary  shareholder and regulatory approvals that
                            may  be  required  to  complete   the   Transaction.
                            Magellan has initiated an audit of BMC and of itself
                            (the "Audits") and estimates that the Audits will be
                            completed no later than April 15, 2005. Magellan has
                            also initiated the  preparation of the Report on the
                            Bulakashu Property (the "Report") and estimates that
                            the Report shall be ready by April 15, 2005;

<PAGE>
                                      -6-


Expenses:                   If the  Transaction  does not close for any  reason,
                            each party will be  responsible  for the  payment of
                            its own expenses in connection  with the Transaction
                            (including,  but not limited to legal and accounting
                            fees, any fees payable to brokers or agents,  or any
                            finder's or other advisory fees);

General:                    This letter  agreement  will be governed by the laws
                            of British  Columbia  and the federal laws of Canada
                            applicable therein;

                            This  letter  agreement  shall be  binding  upon the
                            parties.

This letter  agreement and the  information  contained in this letter  agreement
shall be confidential  and shall not be disclosed by either Magellan or Pubco to
third parties without the written  consent of the other party.  The parties will
co-operate in the making and dissemination of any public announcements  relating
to the subject matter of this letter  agreement,  including a news release to be
issued following  execution hereof  specifying the identities of the parties and
the principal terms of the Transaction.

If the  foregoing  is  acceptable  to you,  please  sign and return  this letter
agreement to us. Facsimile  transmissions  of our respective  signatures of this
letter agreement shall evidence our acceptance of its terms.

Yours truly,

BARADERO RESOURCES LTD.


Per:  /s/ Nick DeMare
     -----------------------
     Nick DeMare, President

Accepted and agreed to as of the date set out above:

FOR AND ON BEHALF                        FOR HIMSELF AND AS ATTORNEY IN FACT FOR
MAGELLAN GOLD CORP.                      THE REMAINING SHAREHOLDERES OF MAGELLAN
                                         GOLD CORP.


Per:  /s/ Doug Turnbull                  /s/ Doug Turnbull
     ------------------------            ------------------------
     Doug Turnbull, President            Doug Turnbull



<PAGE>



                                  SCHEDULE "A"


                      DESCRIPTION OF THE BULAKASHU PROPERTY


Bulakashu  Mining Company  ("BMC") holds License  Au-138-02,  dated November 13,
2002 (the "License").  The License is an exploration license that permits BMC to
explore for gold in the  Bulakashu  Area of the Kyrgyz  Republic,  excluding the
following alluvial gold placer licenses: Upper Karabulak, Lower Karabulak, Upper
Tokailu and Lower Tokailu.



<PAGE>



                                  SCHEDULE "B"

                          LIST OF MAGELLAN SHAREHOLDERS



--------------------------------------------------------------------------------
SHAREHOLDER NAME        NO. OF SHARES        PRICE PAID                DATE PAID
--------------------------------------------------------------------------------

Doug Turnbull             1,600,100            US$0.005     100 on incorporation
                                                                   and 2,000,000
                                                                  acquired in 12
                                                            monthly installments
                                                              beginning in April
                                                            2004 pursuant to his
                                                            employment agreement
                                                                   with Magellan
                                                            (400,000 transferred
                                                            to Cary Pinkowski in
                                                                  February 2005)
--------------------------------------------------------------------------------
Cary Pinkowski            1,000,000            US$0.005        February 25, 2005
                                                            (500,000 acquired by
                                                                  transfers from
                                                          existing shareholders)
--------------------------------------------------------------------------------
Bill Tafuri                 400,000            US$0.005            June 25, 2004
--------------------------------------------------------------------------------
Greg Crowe                  175,000            US$0.005             July 9, 2004
--------------------------------------------------------------------------------
Lindsay Bottomer            175,000            US$0.005             July 9, 2004
--------------------------------------------------------------------------------
James Harris                175,000            US$0.005            June 25, 2004
--------------------------------------------------------------------------------
Robin Merrifield            175,000            US$0.005             Nov. 9, 2004
--------------------------------------------------------------------------------

SUB-TOTAL:               3,700,100
--------------------------------------------------------------------------------