EXHIBIT 4.10


                               AMENDING AGREEMENT

                                     BETWEEN

                            CENTRASIA MINING COMPANY

                                       AND

                             KANTANNA COMPANY LTD.,

                             DATED DECEMBER 14, 2006

                               AS FURTHER AMENDED

                                 AUGUST 17, 2007






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                                 CENTRASIA MINING CORP.
                                 Suite 300, 1055 West Hastings Street,
                                 Vancouver, BC  V6E 2E9 CANADA
                                 Telephone: (604) 688-4110 / Fax: (604) 688-4169
                                 Website  www.centrasiamining.com

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December 14, 2006


Kantanna Company Limited
Akara Bldg., 24 De Castro Street
Wickhams Cay, Road Town
Tortola, British Virgin Islands

Attention:  Oleg Kim


Dear Oleg,

RE:      OPTION   AGREEMENT  DATED  6  JANUARY  2006  (THE   "BULAKASHU   OPTION
         AGREEMENT")  BETWEEN  BULAKASHU  MINING  COMPANY LTD ("BMC"),  KANTANNA
         COMPANY LTD.  ("KANTANNA"),  CENTRASIA MINING CORP.  ("CENTRASIA")  AND
         MAGELLAN GOLD (BVI) INC. ("MAGELLAN")
--------------------------------------------------------------------------------

Pursuant to the Bulakashu Option Agreement, BMC, as a subsidiary of Magellan and
Centrasia,  has been granted an option by Kantanna to acquire a 100% interest in
Bulakashu Property.

Pursuant to section 6(b) of the Bulakashu Option Agreement,  in order for BMC to
exercise the Option and acquire a beneficial interest in the Bulakashu Property,
BMC is required to fund  mineral  exploration  and  development  programs on the
Bulakashu Property by incurring Mining  Expenditures of a minimum  US$690,000.00
in calendar 2006.

We are writing to confirm  that the parties  have agreed to amend the  Bulakashu
Option  Agreement as follows:

1.       Section 6(b) of the Bulakashu  Option  Agreement is amended by deleting
         US$690,000.00  and  replacing  it with  US$200,000.00  and by  deleting
         US$650,000.00 (re Mining  Expenditures for Calendar 2007) and replacing
         it with an  additional  US$490,000.00.  This  would make the total work
         commitment for 2007, US$1,140,000.00.

2.       All capitalized  terms defined in the Bulakashu  Option  Agreement have
         the same meaning in this Amending Letter Agreement.

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


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                                      -2-




If you are in agreement with the terms set out above,  please sign this Amending
Letter Agreement where indicated below and return it to Centrasia.

Yours truly,

FOR AND ON BEHALF OF
CENTRASIA MINING CORP.
MAGELLAN GOLD (BVI) INC. &
BULAKASHU MINING COMPANY LTD



Per:     /s/ Doug Turnbull
         ________________________
         Doug Turnbull



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

FOR AND ON BEHALF OF
KANTANNA COMPANY LIMITED



Per:     /s/ Oleg Kim
         _________________________
         Oleg Kim





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                                 CENTRASIA MINING CORP.
                                 Suite 300, 1055 West Hastings Street,
                                 Vancouver, BC  V6E 2E9 CANADA
                                 Telephone: (604) 688-4110 / Fax: (604) 688-4169
                                 Website  www.centrasiamining.com

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







August 17, 2007


Kantanna Company Limited
Akara Bldg., 24 De Castro Street
Wickhams Cay, Road Town
Tortola, British Virgin Islands

Attention:  Oleg Kim




Dear Oleg,

RE:      OPTION AGREEMENT DATED 6 JANUARY 2006 BETWEEN  BULAKASHU MINING COMPANY
         LTD ("BMC"), KANTANNA COMPANY LTD. ("KANTANNA"), CENTRASIA MINING CORP.
         ("CENTRASIA")  AND MAGELLAN GOLD (BVI) INC.  ("MAGELLAN") AS AMENDED BY
         AN AMENDING  LETTER  AGREEMENT  DATED 14 DECEMBER 2006  (TOGETHER,  THE
         "BULAKASHU OPTION  AGREEMENT")
--------------------------------------------------------------------------------

Pursuant to the Bulakashu Option Agreement, BMC, as a subsidiary of Magellan and
Centrasia,  has been  granted  the  Option by  Kantanna  to acquire up to a 100%
beneficial interest in the Bulakashu Property. To date, BMC has acquired a 37.5%
beneficial  interest in the  Bulakashu  Property by the partial  exercise of the
Option by itself and Centrasia  pursuant to the Bulakashu  Option  Agreement and
predecessor agreements.

Pursuant to section 6 of the  Bulakashu  Option  Agreement,  in order for BMC to
exercise the remaining  unexercised part of the Option and acquire the remaining
62.5% beneficial interest in the Bulakashu Property:

(i)      Centrasia  must issue  375,000  shares of  Centrasia  to Kantanna  (the
         "Remaining Centrasia Shares") on or before December 31, 2007; and

(ii)     BMC is required to fund mineral exploration and development programs on
         the Bulakashu  Property by incurring  Mining  Expenditures of a minimum
         US$1,140,000  in calendar 2007 and of a minimum  US$750,000 in calendar
         2008.

We are writing to confirm  that,  in  consideration  for  Centrasia  issuing the
Remaining  Centrasia  Shares to Kantanna on or before August 31, 2007,  Kantanna
agrees to waive the  requirements  for BMC to incur Mineral  Expenditures on the
Bulakashu  Property during the calendar years 2007 and 2008 in order to exercise
the  unexercised  part  of the  Option.  Therefore,  upon  the  issuance  of the
Remaining  Centrasia  Shares to Kantanna on or before August 31, 2007,  Kantanna
hereby  confirms  that BMC shall be deemed to have  exercised the Option in full
and shall have earned the remaining 62.5%  beneficial  interest in the Bulakashu


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                                      - 2 -




Property,  and  thus  will  have  acquired  a 100%  beneficial  interest  in the
Bulakashu  Property.  The  Bulakashu  Option  Agreement  is deemed to be amended
accordingly.

All capitalized  terms defined in the Bulakashu  Option  Agreement have the same
meaning in this Amending Letter Agreement.

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

If you are in agreement with the terms set out above,  please sign this Amending
Letter Agreement where indicated below and return it to Centrasia.

Yours truly,

FOR AND ON BEHALF OF
CENTRASIA MINING CORP.
MAGELLAN GOLD (BVI) INC. &
BULAKASHU MINING COMPANY LTD



Per:     /s/ Doug Turnbull
         ________________________
         Doug Turnbull



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

FOR AND ON BEHALF OF
KANTANNA COMPANY LIMITED



Per:     /s/ Oleg Kim
         _________________________
         Oleg Kim



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