UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                               ------------------
                                    FORM 11-K
                               ------------------

                     ANNUAL REPORT PURSUANT TO SECTION 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934


(Mark one)

[X]  ANNUAL report pursuant to Section 15(d) of the Securities Exchange Act of
     1934

     For Fiscal year ended December 31, 2005

                                       or

[ ]  Transition report pursuant to Section 15(d) of the Securities Exchange Act
     (No fee required)

             For the transition period from _________ to ___________

Commission file number 001-10533


A. Full title of the plan and the address of the plan, if different from that of
the issuer named below:

                       RIO TINTO AMERICA INC. SAVINGS PLAN

B. Name of issuer of the securities held pursuant to the Plan and the address of
its principal executive office:

         Rio Tinto plc, 6 St. James's Square, London, SW1Y 4LD, England



                               Page 1 of 18 Pages


                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                                               Table of Contents

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


                                                                            Page
                                                                            ----

Report of Independent Registered Public Accounting Firm                        3

Financial Statements:

     Statements of Assets Available for Benefits as of
       December 31, 2005 and 2004                                              4

     Statement of Changes in Assets Available for Benefits
       for the year ended December 31, 2005                                    5

     Notes to Financial Statements                                        6 - 13

Supplemental Schedule - Schedule H, Part IV, line 4i -
  Schedule of Assets (Held at End of Year) as of December 31, 2005       14 - 15

Signature                                                                     16

Exhibits                                                                 17 - 18

All other schedules required by Section 2520.103-10 of the Department of Labor's
Rules and Regulations for Reporting and Disclosure under the Employee Retirement
Income Security Act of 1974 have been omitted because they are not applicable to
the Rio Tinto America Inc. Savings Plan.




                               Page 2 of 18 Pages



                                         REPORT OF INDEPENDENT REGISTERED PUBLIC
                                                                 ACCOUNTING FIRM


The Rio Tinto America Inc. Savings Plan Investment Committee
  and the Rio Tinto America Inc. Benefits Committee
Rio Tinto America Inc. Savings Plan


We have audited the accompanying  statements of assets available for benefits of
the Rio Tinto  America Inc.  Savings Plan (the Plan) as of December 31, 2005 and
2004 and the related  statement of changes in assets  available for benefits for
the  year  ended  December  31,  2005.   These  financial   statements  are  the
responsibility  of the Plan's  management.  Our  responsibility is to express an
opinion on these financial statements based on our audits.

We conducted  our audits in  accordance  with  standards  of the Public  Company
Accounting Oversight Board (United States). Those standards require that we plan
and  perform  the  audits to  obtain  reasonable  assurance  about  whether  the
financial  statements  are free of  material  misstatement.  An  audit  includes
consideration  of  internal  control  over  financial  reporting  as a basis for
designing audit  procedures that are appropriate in the  circumstances,  but not
for the  purpose of  expressing  an opinion on the  effectiveness  of the Plan's
internal  control  over  financial  reporting.  Accordingly,  we express no such
opinion. An audit includes examining,  on a test basis,  evidence supporting the
amounts and  disclosures  in the  financial  statements.  An audit also includes
assessing the  accounting  principles  used and  significant  estimates  made by
management,  as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.

In our opinion,  the financial  statements  referred to above present fairly, in
all  material  respects,  the assets  available  for  benefits  of the Rio Tinto
America Inc.  Savings Plan as of December 31, 2005 and 2004,  and the changes in
assets available for benefits for the year ended December 31, 2005 in conformity
with U.S. generally accepted accounting principles.

Our audits of the financial statements were performed for the purpose of forming
an opinion on the basic financial  statements taken as a whole. The supplemental
Schedule of Assets  (Held at End of Year) as of December  31, 2005 is  presented
for the purpose of  additional  analysis and is not a required part of the basic
financial  statements,  but is supplementary  information required by the United
States  Department of Labor's Rules and Regulations for Reporting and Disclosure
under the Employee  Retirement  Income  Security Act of 1974.  The  supplemental
schedule is the  responsibility  of the Plan's management and has been subjected
to the  auditing  procedures  applied  in the  audits  of  the  basic  financial
statements  and, in our opinion,  is fairly  stated in all material  respects in
relation to the basic financial statements taken as a whole.

/s/ Tanner LC

Salt Lake City, Utah
June 28, 2006


                               Page 3 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                     STATEMENTS OF ASSETS AVAILABLE FOR BENEFITS

                                                                    December 31,
--------------------------------------------------------------------------------

                                                     2005                2004
                                                --------------------------------
Assets

Investments                                      $436,830,392       $399,342,069
                                                --------------------------------

Receivables:
  Employee contributions                              317,402             23,887
  Employer contributions                              189,759             14,387
                                                --------------------------------

          Total receivables                           507,161             38,274
                                                --------------------------------

Assets available for benefits                    $437,337,553       $399,380,343
                                                ================================



--------------------------------------------------------------------------------
See accompanying notes to financial statements.



                               Page 4 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                           STATEMENT OF CHANGES IN ASSETS AVAILABLE FOR BENEFITS

                                                    YEAR ENDED DECEMBER 31, 2005
--------------------------------------------------------------------------------

ADDITIONS TO ASSETS ATTRIBUTED TO:
  Transfers:
    From the U.S. Borax Inc. 401(k) Plan for Hourly
     Employees                                                      $    551,656
    From the Kennecott Corporation Savings Plan
     for Hourly Employees                                              1,620,480
                                                                    ------------

          Total transfers                                              2,172,136
                                                                    ------------

  Contributions:
    Employee                                                          20,556,036
    Employer                                                          10,544,179
                                                                    ------------

          Total contributions                                         31,100,215
                                                                    ------------

  Investment income:
    Net appreciation in fair value of investments                     19,784,533
    Interest and dividends                                            15,418,063
                                                                    ------------

          Total investment income                                     35,202,596
                                                                    ------------

          Total additions                                             68,474,947
                                                                    ------------

DEDUCTIONS FROM ASSETS ATTRIBUTED TO:
  Benefits paid to participants                                       30,513,440
  Administrative expenses                                                  4,297
                                                                    ------------

          Total deductions                                            30,517,737
                                                                    ------------

Increase in assets available for benefits                             37,957,210

ASSETS AVAILABLE FOR BENEFITS:
  Beginning of year                                                  399,380,343
                                                                    ------------

  End of year                                                       $437,337,553
                                                                    ============

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

See accompanying notes to financial statements.



                               Page 5 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                                   NOTES TO FINANCIAL STATEMENTS


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

1.   DESCRIPTION OF       The  following  brief  description  of the  Rio  Tinto
     THE PLAN             America  Inc.  Savings Plan (the Plan) is provided for
                          general information purposes only. Participants should
                          refer  to  the  Plan   document   and   summary   plan
                          description for more complete information.

                          GENERAL
                          The Plan is a defined  contribution  plan covering (1)
                          all  non-represented  employees of Rio Tinto  America,
                          Inc. and its affiliates  (collectively,  the Company),
                          as defined  in the Plan  document,  and (2)  employees
                          covered  by a  collective  bargaining  agreement  that
                          provides   for  Plan   participation.   All   eligible
                          full-time  employees of the Company can participate in
                          the Plan immediately  upon  employment.  Temporary and
                          part-time  employees  are  eligible  after  completing
                          1,000 hours of service during a 12-month  period.  Rio
                          Tinto  America,  Inc.  is  an  indirect  wholly  owned
                          subsidiary of Rio Tinto plc (the Parent). The Plan was
                          created  effective January 1, 2003, by a merger of the
                          Kennecott  Savings and Investment Plan, the U.S. Borax
                          Inc.  Thrift  Plan  for  Salaried  Employees,  and the
                          Luzenac  America,  Inc.  Investment  Savings Plan. The
                          Plan is  intended to be a  qualified  retirement  plan
                          under the  Internal  Revenue Code (IRC) and is subject
                          to the  provisions of the Employee  Retirement  Income
                          Security Act of 1974 (ERISA), as amended.

                          CONTRIBUTIONS
                          Each  year,  participants  may  elect  under a  salary
                          reduction  agreement  to  contribute  to the  Plan  an
                          amount not less than 1% and not more than 50% of their
                          eligible  compensation  on a before-tax  basis through
                          payroll  deductions.  Contributions are limited by the
                          IRC,  which  established  a  maximum  contribution  of
                          $14,000 ($18,000 for participants over age 50) for the
                          year ended  December 31, 2005.  Participants  may also
                          elect to make an after-tax  contribution not less than
                          1%  and  not  more   than   50%  of   their   eligible
                          compensation.    Total    before-tax   and   after-tax
                          contributions   cannot  exceed  50%  of  participants'
                          eligible compensation.  Participant  contributions are
                          recorded  in the period  during  which the amounts are
                          withheld from participant  earnings.  Participants may
                          also  contribute  amounts  representing  distributions
                          from  other  qualified   defined  benefit  or  defined
                          contribution plans.

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


                               Page 6 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                                   NOTES TO FINANCIAL STATEMENTS
                                                                       CONTINUED

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

1.   DESCRIPTION OF       The Company matches the participants' contributions to
     THE PLAN             the Plan at 100%, up to the first 6% of their eligible
     CONTINUED            compensation,  for all  locations  other than  Luzenac
                          America,  Inc. The Company  matches the  participants'
                          contributions  to the Plan at 70%,  up to the first 6%
                          of their eligible  compensation,  for Luzenac America,
                          Inc.  employees  other than the following:  (1) hourly
                          employees of Luzenac America,  Inc. at the Three Forks
                          Mill who are  represented by the United Cement,  Lime,
                          and  Allied  Workers'  Division  of the  International
                          Brotherhood   of   Boilermakers   and  (a)  who   made
                          contributions after August 1, 2003 and prior to August
                          1, 2005 received a match of 45%, up to the first 6% of
                          eligible  compensation;  and  (b)  made  contributions
                          after  August 1, 2005  received a match of 50%,  up to
                          the  first  6%  of  eligible  compensation;   and  (2)
                          effective  May 12, 2004,  hourly  employees of Luzenac
                          America,  Inc. at the Windsor Mine who are represented
                          by  the  United  Cement,  Lime,  and  Allied  Workers'
                          Division   of   the   International   Brotherhood   of
                          Boilermakers  received a match of 40%, up to the first
                          6% of eligible  compensation  (prior to May 12,  2004,
                          hourly  employees  of  Luzenac  America,  Inc.  at the
                          Windsor Mine who are represented by the United Cement,
                          Lime,   and   Allied   Workers'    Division   of   the
                          International  Brotherhood of Boilermakers  received a
                          match  of  25%,   up  to  the  first  6%  of  eligible
                          compensation).  Matching contributions are recorded on
                          the date the  related  participant  contributions  are
                          withheld.

                          PARTICIPANT ACCOUNTS
                          Individual  accounts  are  maintained  for  each  Plan
                          participant.  Each  participant's  account is credited
                          with the  participant's  contributions,  the Company's
                          matching contribution, and an allocation of the Plan's
                          earnings,  and  is  charged  with  withdrawals  and an
                          allocation  of the Plan's  losses  and  administrative
                          expenses.   Allocations   are  based  on   participant
                          earnings or account balances,  as defined. The benefit
                          to which a participant is entitled is the benefit that
                          can be provided from the participant's vested account.

                          PARTICIPANT-DIRECTED OPTIONS FOR INVESTMENTS
                          Participants    direct   the   investment   of   their
                          contributions  and the Company matching  contributions
                          into various  investment  options offered by the Plan.
                          Investment options include a money market fund, common
                          collective trusts, mutual funds, guaranteed investment
                          contracts,  synthetic guaranteed  investment contracts
                          and common stock of the Parent in the form of American
                          Depository Receipts (ADRs).

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


                               Page 7 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                                   NOTES TO FINANCIAL STATEMENTS
                                                                       CONTINUED

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

1.   DESCRIPTION OF       VESTING
     THE PLAN             Participants   are   immediately   vested   in   their
     CONTINUED            contributions and Company matching  contributions plus
                          actual earnings thereon.

                          PAYMENT OF BENEFITS
                          On termination of service due to death, disability, or
                          retirement,  participants or their  beneficiaries  may
                          elect to  receive  lump-sum  distributions  or annual,
                          semi-annual,  quarterly  or  monthly  installments  in
                          amounts equal to the value of the participants' vested
                          interests   in   their    accounts.    Under   certain
                          circumstances,   participants   may   withdraw   their
                          contributions prior to the occurrence of these events.

                          TRANSFERS
                          Along with the Plan,  the Company also sponsors  other
                          401(k)  plans that  cover  represented  employees.  If
                          employees  are changed from union to non-union  status
                          during   the  year,   their   account   balances   are
                          transferred  from the union plan to this Plan. For the
                          year ended December 31, 2005,  transfers into the Plan
                          totaled  $2,172,136.  For the year ended  December 31,
                          2005,  transfers from the U.S. Borax Inc.  401(k) Plan
                          for Hourly  Employees  totaled  $551,656 and transfers
                          from the Kennecott Corporation Savings Plan for Hourly
                          Employees totaled $1,620,480.

                          FORFEITED ACCOUNTS
                          As of January 1, 2003,  the effective  date of the Rio
                          Tinto America Inc.  Savings Plan,  there was a balance
                          in  the  forfeiture  account  related  to  predecessor
                          plans' non-vested participant account balances.  These
                          amounts   may  be  used  to  reduce   future   Company
                          contributions  to the  Plan.  During  the  year  ended
                          December  31,  2005,  the  forfeiture  account  earned
                          $3,158  and no  forfeitures  were  utilized  to reduce
                          Company   contributions.   Under  the  Plan  document,
                          forfeiture amounts related to terminated  participants
                          are   required   to  be  held  for  five  years  after
                          termination  in  the  event  that  the  individual  is
                          re-hired  and  becomes  a  participant  again.  If the
                          employee  becomes a participant  within that five-year
                          period,  the service period resumes for vesting of the
                          participant's   account.   If  the  five-year   period
                          expires,  the forfeitures  become  available to reduce
                          future Company  contributions to the Plan.  Additional
                          forfeitures  that became available for general use for
                          the year ended December 31, 2005 totaled  $48,889.  As
                          of  December  31,  2005 and 2004,  the  balance in the
                          forfeiture    account   was   $84,507   and   $32,460,
                          respectively.

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


                               Page 8 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                                   NOTES TO FINANCIAL STATEMENTS
                                                                       CONTINUED

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

2.   SUMMARY OF           BASIS OF PRESENTATION
     SIGNIFICANT          The  financial   statements  of  the  Plan  have  been
     ACCOUNTING           prepared  on  the  accrual   basis  of  accounting  in
     POLICIES             accordance  with U.S.  generally  accepted  accounting
                          principles.

                          USE OF ESTIMATES
                          The preparation of the Plan's financial  statements in
                          conformity  with U.S.  generally  accepted  accounting
                          principles  requires Plan management to make estimates
                          and  assumptions  that affect the reported  amounts of
                          assets  available  for  benefits  at the  date  of the
                          financial statements,  the changes in assets available
                          for benefits  during the  reporting  period and,  when
                          applicable,  the disclosures of contingent  assets and
                          liabilities  at the date of the financial  statements.
                          Actual results could differ from those estimates.

                          RISKS AND UNCERTAINTIES
                          The Plan provides for  investments in securities  that
                          are exposed to various  risks,  such as interest rate,
                          currency  exchange  rate,  credit and  overall  market
                          fluctuation.  Due to the level of risk associated with
                          certain  investment   securities,   it  is  reasonably
                          possible  that  changes  in the  values of  investment
                          securities  will  occur in the near term and that such
                          changes could materially affect participants'  account
                          balances and the amounts reported in the statements of
                          assets available for benefits.

                          INVESTMENT VALUATION AND INCOME RECOGNITION
                          The  Plan's  investments  are  stated  at  fair  value
                          (generally   quoted   market  price)  except  for  its
                          benefit-responsive  guaranteed  investment  contracts,
                          which are  stated at  contract  value (see Note 6) and
                          participant   loans,   which   are   stated  at  their
                          outstanding  balances,  which approximate fair values.
                          Shares of mutual  funds  are  stated at quoted  market
                          prices,  which represent the net asset value of shares
                          held by the Plan at year end.

                          Purchases  and sales of  securities  are recorded on a
                          trade-date  basis.  Interest income is recorded on the
                          accrual   basis.   Dividends   are   recorded  on  the
                          ex-dividend date.

                          PAYMENTS OF BENEFITS
                          Benefits payments are recorded when paid by the Plan.

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


                               Page 9 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                                   NOTES TO FINANCIAL STATEMENTS
                                                                       CONTINUED

--------------------------------------------------------------------------------
2.   SUMMARY OF           ADMINISTRATIVE EXPENSES
     SIGNIFICANT          The  Company  pays  the  majority  of  the  costs  and
     ACCOUNTING           expenses incurred in administering the Plan.
     POLICIES
     CONTINUED            The Plan has  several  fund  managers  that manage the
                          investments  held by the Plan.  During  the year ended
                          December  31, 2005,  the Company  paid all  investment
                          management fees related to these investment funds.

                          The investment  management fees related to transaction
                          costs  associated  with  the  purchase  or sale of Rio
                          Tinto plc ADRs are paid by the participants.

                          PARTICIPANT LOANS
                          Participants  may borrow from the Plan up to a maximum
                          of $50,000 or 50% of their account balances, whichever
                          is less.  Each loan is secured  by the  balance in the
                          participant's  account  and bears  interest  at a rate
                          commensurate  with prevailing  rates at the time funds
                          are    borrowed,    as    determined   by   the   Plan
                          Administrators. Loans originated during the year ended
                          December  31,  2005 have  interest  rates set at prime
                          plus one  percent.  Principal  and  interest  are paid
                          ratably through payroll deductions.

                          NEW ACCOUNTING PRONOUNCEMENT
                          In December 2005, the Financial  Accounting  Standards
                          Board (FASB) issued FASB Staff  Position AAG INV-1 and
                          SOP  94-4-1,  Reporting  of  Fully  Benefit-Responsive
                          Investment   Contracts  Held  by  Certain   Investment
                          Companies  Subject  to the  AICPA  Investment  Company
                          Guide and Defined-Contribution  Health and Welfare and
                          Pension Plans (FSP).  This FSP makes the definition of
                          benefit-responsive  more  restrictive  so that certain
                          investment  contracts  currently  reported at contract
                          value may be reported at fair  value.  Management  has
                          not yet determined the impact this standard,  which is
                          effective for the plan year ending  December 31, 2006,
                          will have on the Plan's financial statements.


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


                               Page 10 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                                   NOTES TO FINANCIAL STATEMENTS
                                                                       CONTINUED

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

3.   PARTIES-IN-          Certain  Plan   investments   are  managed  by  Putnam
     INTEREST             Investments,   the  Plan  trustee,   therefore,  these
     TRANSACTIONS         transactions     are     exempt      party-in-interest
                          transactions.  Fees  paid by the Plan  for  investment
                          management  services  were  included as a reduction of
                          the return earned on each fund.

                          Transactions  associated  with Rio  Tinto plc ADRs are
                          considered   exempt   party-in-interest   transactions
                          because Rio Tinto plc is the parent of the Company. As
                          of  December   31,  2005  and  2004,   the  Plan  held
                          167,436.747 and 139,657.081 shares,  respectively,  of
                          common  stock of Rio Tinto  plc,  with a cost basis of
                          $16,272,106 and $10,620,880,  respectively. During the
                          year  ended  December  31,  2005,  the  Plan  recorded
                          dividend  income of $490,345  related to the Rio Tinto
                          plc ADRs.

4.   INVESTMENTS          The Plan's  investments  that represented five percent
                          or more of the Plan's assets available for benefits as
                          of December 31, 2005 and 2004 are as follows:

                                                             2005       2004
                                                         ----------------------

                          Dodge and Cox Stock Fund       $67,357,011 $25,328,751
                          Monumental Life Insurance
                            Company Synthetic GIC         55,074,136  52,444,261
                          State Street Bank Synthetic
                            GIC                           40,739,730  39,101,619
                          Putnam S&P 500 Index Fund       38,803,876  31,574,647
                          Putnam Voyager Fund             37,639,071  29,928,356
                          Rio Tinto plc ADRs              30,605,763  16,648,521
                          SEI Stable Asset Fund           30,445,798  11,905,589
                          Putnam International Equity
                            Fund                          25,675,260  21,911,615
                          PIMCO Total Return Fund         22,846,685  15,835,529
                          Putnam Fund for Growth
                            and Income                        *       34,634,858
                          Putnam New Opportunities Fund       *       32,924,760

                          * These  investments  did not exceed  five  percent or
                          more of total  assets  available  for  benefits  as of
                          December  31,  2005  and,  therefore,  are  not  shown
                          separately.

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


                               Page 11 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                                   NOTES TO FINANCIAL STATEMENTS
                                                                       CONTINUED

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

4.   INVESTMENTS          During the year ended  December 31,  2005,  the Plan's
     CONTINUED            investments (including gains and losses on investments
                          bought  and  sold,  as well as held  during  the year)
                          appreciated in fair value as follows:


                             Mutual funds                           $ 7,557,901
                             Common stock                            10,378,331
                             Common collective trusts                 1,848,301
                                                                     -----------

                             Net appreciation in investments         $19,784,533
                                                                     ===========

5.   PLAN                 Although it has not  expressed any intention to do so,
     TERMINATION          the   Company   has  the  right   under  the  Plan  to
                          discontinue  its  contributions  at  any  time  and to
                          terminate the Plan subject to the provisions set forth
                          in ERISA.

6.   GUARANTEED           The Plan's  guaranteed  investment  contracts are in a
     INVESTMENT           stable value fund. The guaranteed investment contracts
     CONTRACTS            are  fully   benefit-responsive   and  are  stated  at
                          contract value (which  represents  contributions  made
                          under  the  contract,   plus  interest  earned,   less
                          withdrawals and administrative  expenses).  The stable
                          value  fund is  invested  in a money  market  fund,  a
                          common  collective  trust (the SEI Stable Asset Fund),
                          guaranteed  investment contracts (GICs), and synthetic
                          GICs.  The  synthetic  GICs are secured by  underlying
                          fixed income assets.  The average  crediting  interest
                          rates on the investment contracts were 4.79% and 4.61%
                          for the  years  ended  December  31,  2005  and  2004,
                          respectively.  Average  duration  for  all  investment
                          contracts  was 3.06 years and 3.01  years at  December
                          31, 2005 and 2004, respectively. The average yield was
                          4.82% and 4.63% for the years ended  December 31, 2005
                          and 2004, respectively.  There are no reserves against
                          the contract  value for credit risk of the  contracted
                          issuer or otherwise.

                          The contract or crediting  interest  rates for certain
                          stable value investment  contracts are reset quarterly
                          and are based on the market value of the  portfolio of
                          assets  underlying  these  contracts.  Inputs  used to
                          determine  the crediting  interest  rates include each
                          contract's    portfolio    market    value,    current
                          yield-to-date  maturity,  duration  and  market  value
                          relative to contract  value.  With respect to interest
                          rate resets,  all  contracts are  guaranteed  that the
                          rates will not be negative.

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


                               Page 12 of 18 Pages



                                             RIO TINTO AMERICA INC. SAVINGS PLAN
                                                   NOTES TO FINANCIAL STATEMENTS
                                                                       CONTINUED

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

6.   GUARANTEED           A synthetic  GIC provides  for a guaranteed  return on
     INVESTMENT           principal  over a  specified  period  of time  through
     CONTRACTS            fully  benefit-responsive wrap contracts,  issued by a
     CONTINUED            third party which are backed by underlying assets. The
                          portfolio of assets  underlying the synthetic GICs has
                          an overall AAA credit quality and includes  mortgages,
                          fixed income  securities  and United  States  treasury
                          notes and bonds. These wrap contracts provide benefits
                          withdrawals  and  investment  exchanges  at  the  full
                          contract value of the synthetic  contracts  (principal
                          plus  accrued  interest)  notwithstanding  the  actual
                          market value of the underlying investments (fair value
                          plus accrued interest).

                          Wrap  contracts  are designed to smooth out the impact
                          of  normal  market  fluctuations  associated  with the
                          performance  of the underlying  investments.  The fair
                          value  of  the  synthetic  GICs  was  $96,013,693  and
                          $93,709,918   as  of  December   31,  2005  and  2004,
                          respectively. The contract value of the synthetic GICs
                          included  $22,580 and  $2,164,038  as of December  31,
                          2005 and 2004, respectively,  attributable to the wrap
                          contract  providers  representing the amounts by which
                          the net  value of the  contracts  is less than the net
                          value of the underlying assets.

7.   INCOME TAX           The Plan does not have a determination letter from the
     STATUS               Internal  Revenue  Service  informing it that the Plan
                          and related trust are designed in accordance  with the
                          applicable  requirements of the Internal Revenue Code.
                          However,  the Plan  Administrator and the Plan's legal
                          counsel  believe that the Plan is  currently  designed
                          and being  operated in compliance  with the applicable
                          requirements of the Internal Revenue Code.  Therefore,
                          no provision for income taxes has been included in the
                          Plan's financial statements.

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


                               Page 13 of 18 Pages





                                                                                                RIO TINTO AMERICA INC. SAVINGS PLAN
                                                                                        EMPLOYER IDENTIFICATION NUMBER:  11-3359689
                                                                                                                  PLAN NUMBER:  002
                                                                                                       SCHEDULE H, PART IV, LINE 4i
                                                                                           SCHEDULE OF ASSETS (HELD AT END OF YEAR)
                                                                                                                  DECEMBER 31, 2005
-----------------------------------------------------------------------------------------------------------------------------------


  (a)                  (b)                                (c)                                         (d)             (e)
PARTY IN                                                                               NUMBER OF                    CURRENT
INTEREST       IDENTITY OF ISSUE                DESCRIPTION OF INVESTMENT                UNITS        COST           VALUE
----------   ---------------------    ----------------------------------------------  -----------   --------   -------------------
                                                                                                
                                      MONEY MARKET FUND:
             Mellon Bank              Mellon Bank - STIF Account                        1,127,156      **        $  1,127,156
                                                                                                                 --------------

                                      COMMON COLLECTIVE TRUSTS:
             SEI Investments          SEI Stable Asset Fund                                            **          30,445,798
   *         Putnam                   Putnam S&P 500 Index Fund                         1,206,213      **          38,803,876
                                                                                                                 --------------
                                                Total Common Collective Trusts                                     69,249,674
                                                                                                                 --------------

                                      MUTUAL FUNDS:
             Dreyfus                  Dreyfus Mid-Cap Value Fund                          512,575      **          16,243,501
             PIMCO                    PIMCO Total Return Fund                           2,175,875      **          22,846,685
             Morgan Stanley           MSDW Institutional International Equity Fund        562,121      **          11,433,536
             Dodge and Cox            Dodge and Cox Stock Fund                            490,869      **          67,357,011
             UAM Trust Company        UAM/ICM Small Company Fund                          373,462      **          13,530,520
             Artisan                  Artisan Mid Cap Fund                                609,647      **          18,850,277
   *         Putnam                   Putnam Small Cap Growth Fund CL Y                   584,392      **          13,031,948
   *         Putnam                   Putnam International Equity Fund                    976,617      **          25,675,260
   *         Putnam                   Putnam Voyager Fund                               2,096,884      **          37,639,071
                                                                                                                 --------------
                                                Total Mutual Funds                                                226,607,809
                                                                                                                 --------------

                                      GUARANTEED INVESTMENT CONTRACTS:
             Monumental Life
               Insurance Company      GIC, due 6/15/07, 4.11%                                          **           1,011,713
             Monumental Life
               Insurance Company      GIC, due 12/17/07, 4.11%                                         **           1,032,692
                                                                                                                 --------------
                                                Total Guaranteed Investment Contracts                               2,044,405
                                                                                                                 --------------

*  denotes a party-in-interest as defined by ERISA
** not required as investments are participant directed

-------------------------------------------------------------------------------------------------------------------------------
See accompanying report of independent registered public accounting firm.



                              Page 14 of 18 Pages





                                                                                                RIO TINTO AMERICA INC. SAVINGS PLAN
                                                                                        EMPLOYER IDENTIFICATION NUMBER:  11-3359689
                                                                                                                  PLAN NUMBER:  002
                                                                                                       SCHEDULE H, PART IV, LINE 4i
                                                                                           SCHEDULE OF ASSETS (HELD AT END OF YEAR)
                                                                                                                          CONTINUED
                                                                                                                  DECEMBER 31, 2005
-----------------------------------------------------------------------------------------------------------------------------------


  (a)                  (b)                                (c)                                         (d)             (e)
PARTY IN                                                                               NUMBER OF                    CURRENT
INTEREST       IDENTITY OF ISSUE                DESCRIPTION OF INVESTMENT                UNITS        COST           VALUE
----------   ---------------------    ----------------------------------------------  -----------   --------   -------------------
                                                                                                
                                      SYNTHETIC GUARANTEED INVESTMENT CONTRACTS:
             Monumental Life          Synthetic GIC, Dwight Core Int Fund, no
               Insurance Company        specified maturity date, 5.01%                                 **      $    1,790,009
             Monumental Life          Synthetic GIC, Dwight Managed Target 2,
               Insurance Company        no specified maturity date, 5.01%                              **          28,915,252
             Monumental Life          Synthetic GIC, Dwight Managed Target 5,
               Insurance Company        no specified maturity date, 5.01%                              **          24,546,122
             Monumental Life          Wrap Contract                                                    **            (177,247)
               Insurance Company

             State Street Bank        Synthetic GIC, Dwight Core Int Fund, no
                                        specified maturity date, 4.76%                                 **          11,340,907
             State Street Bank        Synthetic GIC, Dwight Managed Target 2,
                                        no specified maturity date, 4.76%                              **          22,244,604
             State Street Bank        Synthetic GIC, Dwight Managed Target 5,
                                        no specified maturity date, 4.76%                              **           7,154,219
             State Street Bank        Wrap Contract                                                    **             199,827
                                                                                                                 --------------
                                                  Total Synthetic Guaranteed
                                                    Investment Contracts                                           96,013,693
                                                                                                                 --------------

   *         Rio Tinto plc ADRs       COMMON STOCK                                        167,437      **          30,605,763
                                                                                                                 --------------

   *         Putnam                   PENDING ACCOUNT                                                  **             261,193
                                                                                                                 --------------
   *         Various participants     PARTICIPANT LOANS (maturing 2006 to 2032
                                        at interest rates ranging from 5.0% to
                                        10.5%)                                              1,193      **          10,920,699
                                                                                                                 --------------

                                                  Total Investments                                              $436,830,392
                                                                                                                 ==============

*  denotes a party-in-interest as defined by ERISA
** not required as investments are participant directed

-------------------------------------------------------------------------------------------------------------------------------
See accompanying report of independent registered public accounting firm.



                              Page 15 of 18 Pages



                                    SIGNATURE

         Pursuant to the  requirements  of the Securities  Exchange Act of 1934,
the trustees (or other persons who  administer  the employee  benefit plan) have
duly  caused this  annual  report to be signed on its behalf by the  undersigned
hereunto duly authorized.


                                             RIO TINTO AMERICA INC. SAVINGS PLAN



                                             By: /s/ Christopher Crowl
                                                --------------------------------
                                                Name:  Christopher Crowl
                                                Title: Rio Tinto America Inc.
                                                       Benefits Committee Member

Date:  June 29, 2006



                              Page 16 of 18 Pages




Exhibit        Description
-------        -----------

23.1           Consent of Tanner LC





                              Page 17 of 18 Pages