Exhibit 99.1

Disclosure of Mine Safety and Health Administration (MSHA) Safety Data

Rio
Tinto is committed to the health and safety of its employees and in providing an incident free workplace. The Company maintains a comprehensive health and safety program that includes extensive training for all employees and contractors, site
inspections, emergency response preparedness, crisis communications training, incident investigation, regulatory compliance training and process auditing.

Rio Tintos U.S. mining operations are subject to MSHA regulation under the U.S. Federal Mine Safety and Health Act of 1977 (the Mine Act). MSHA inspects our mines on a regular basis and
issues various citations and orders when it believes a violation has occurred under the Mine Act. Whenever MSHA issues a citation or order, it also generally proposes a civil penalty, or fine, related to the alleged violation.

The following disclosures are provided pursuant to Section 1503(a) of the Dodd-Frank Wall Street Reform and Consumer Protection Act (the
Act), which requires certain disclosures by companies required to file periodic reports under the Securities Exchange Act of 1934 that operate mines regulated under the Mine Act. The disclosures reflect our U.S. mining operations only as
the requirements of the Act do not apply to our mines operated outside the U.S.

The information in the table below reflects citations and
orders MSHA issued to Rio Tinto during the year ended 31 December, 2012, as reflected in our records. The data in our system may not match or reconcile with the data MSHA maintains on its public website. In evaluating this information, consideration
should also be given to factors such as: (i) the number of citations and orders may vary depending on the size and operation of the mine, (ii) the number of citations issued may vary from inspector to inspector and mine to mine, and
(iii) citations and orders may be contested and appealed, and in that process, may be reduced in severity and amount, and may be dismissed.



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|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 |  |  |                          |   |  |                                                 |  |   |                                      |  |   |                                                               |  |                                                                    |  |                                              |  |                                           |    |                                   |    |                                  |   |  |  |   |  |  |   |  |  |   |  |  |  |  | 
|----------------- |  | -------------------------------------------------- |  | ------------------------------------------------- | -- |  | ------------------------ |  | - | ----------------------------------- |  |  | ------------------------------- |  |  | ------------------------ | - |  | ----------------------------------------------- |  | - | ------------------------------------ |  | - | ------------------------------------------------------------- |  | ------------------------------------------------------------------ |  | -------------------------------------------- |  | ----------------------------------------- | -- | --------------------------------- | -- | -------------------------------- | - |  |  | - |  |  | - |  |  | - |  |  |  |  | 
|Mine ID number(1) |  | Mine or
Operating
Name                             |  | Section104SignificantandSubstantialCitations 
(2) |    |  | Section104(b)Orders 
(3) |  |   | Section104(d)CitationsandOrders (4) |  |  | Section110(b)(2)Violations 
(5) |  |  | Section107(a)Orders 
(6) |   |  | Total dollarvalue ofMSHAassessmentsproposed (7) |  |   | TotalnumberofMiningRelatedFatalities |  |   | ReceivedNotice ofPattern ofViolationsUnderSection104(e)yes/no |  | ReceivedNotice ofPotential toHave Patternunder section104(e)yes/no |  | LegalActionsPendingas of LastDay ofPeriod(8) |  | CategoriesofPendingLegalActions(i-vii)(9) |    | LegalActionsInitiatedDuringPeriod |    | LegalActionsResolvedDuringPeriod |  
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|4202040           |  | Kennecott Barneys Canyon Mining                    |  |                                                   | 0  |  |                          |  | 0 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  |   | 0                                                             |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 0 |  |  | 0 |  |  | 0 |  |  | 0 | 
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|2000420           |  | Kennecott Eagle Land LLC                           |  |                                                   | 0  |  |                          |  | 0 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  |   | 0                                                             |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 0 |  |  | 0 |  |  | 0 |  |  | 0 | 
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|2003454           |  | Kennecott Eagle Minerals Co                        |  |                                                   | 0  |  |                          |  | 0 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  | $ | 700                                                           |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 0 |  |  | 0 |  |  | 0 |  |  | 0 | 
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|4200149           |  | Kennecott Utah Copper LLC (Bingham Canyon)         |  |                                                   | 5  |  |                          |  | 0 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  | $ | 5,837                                                         |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 0 |  |  | 0 |  |  | 0 |  |  | 1 | 
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|4201996           |  | Kennecott Utah Copper LLC (Copperton Concentrator) |  |                                                   | 0  |  |                          |  | 0 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  | $ | 2,121                                                         |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 0 |  |  | 0 |  |  | 0 |  |  | 0 | 
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|400743            |  | US Borax Inc (Boran)                               |  |                                                   | 12 |  |                          |  | 0 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  | $ | 60,983                                                        |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 6 |  |  | 6 |  |  | 4 |  |  | 5 | 
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|402834            |  | US Borax Inc (Owens Lake)                          |  |                                                   | 0  |  |                          |  | 0 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  |   | 0                                                             |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 0 |  |  | 0 |  |  | 0 |  |  | 0 | 
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|200152            |  | Resolution Copper Mining LLC                       |  |                                                   | 0  |  |                          |  | 3 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  | $ | 307                                                           |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 0 |  |  | 0 |  |  | 0 |  |  | 0 | 
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|4201392           |  | Kennecott Keystone Underground                     |  |                                                   | 2  |  |                          |  | 0 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  | $ | 1,268                                                         |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 0 |  |  | 0 |  |  | 0 |  |  | 0 | 
|                  |  |                                                    |  |                                                   |    |  |                          |  |   |                                     |  |  |                                 | 
|4503702           |  | Holden Mine Remediation*                           |  |                                                   | 0  |  |                          |  | 0 |                                     |  |  | 0                               |  |  |                          | 0 |  |                                                 |  | 0 |                                      |  |   | 0                                                             |  |                                                                    |  | 0                                            |  |                                           | no |                                   | no |                                  | 0 |  |  | 0 |  |  | 0 |  |  | 0 | 



|* | Represents a new entity, statistics listed are for the period starting on 25 April 2012, the date of the start of the new operation.
|- | ------------------------------------------------------------------------------------------------------------------------------------

|(1) | MSHA assigns an identification number to each mine or operation and may or may not assign separate identification number to related facilities. The information provided
in this table is presented by mine identification number.
|--- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|(2) | Represents the total number of citations issued by MSHA for violation of health or safety standards that could significantly and substantially contribute to a serious
injury if left unabated.
|--- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|(3) | Represents the total number of orders issued, which represents a failure to abate a citation under section 104(a) within the period prescribed by MSHA. This results in
an order of immediate withdrawal from the area of the mine affected by the condition until MSHA determines that the violation has been abated.
|--- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|(4) | Represents the total number of citation and orders issued by MSHA for unwarrantable failure to comply with mandatory health or safety standards.
|--- | ------------------------------------------------------------------------------------------------------------------------------------------------

|(5) | Represents the total number of flagrant violations identified.
|--- | --------------------------------------------------------------

|(6) | Represents the total number of imminent danger orders issued under section 107(a) of the Mine Act.
|--- | --------------------------------------------------------------------------------------------------

|(7) | Amounts represent the total dollar value of proposed assessments received from MSHA.
|--- | ------------------------------------------------------------------------------------

|(8) | Pending legal actions before the Federal Mine Safety and Health Review Commission (the Commission) as required to be reported by Section 1503(a)(3) of
the Act.
|--- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------

|(9) | The following provides additional information regarding the types or categories of proceedings that may be brought before the commission.
|--- | -----------------------------------------------------------------------------------------------------------------------------------------

| | (i) | Contest Proceedings - a contest proceeding may be filed with the Commission by an operator to challenge the issuance of a citation or order issued by MSHA;
| | --- | -----------------------------------------------------------------------------------------------------------------------------------------------------------

| | (ii) | Civil Penalty Proceedings - a civil penalty proceeding may be filed with the Commission by an operator to challenge a civil penalty MSHA has proposed for a violation
contained in a citation or order;
| | ---- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



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| | (iii) | Discrimination Proceedings - a discrimination proceeding involves a miners allegation that he or she has suffered adverse employment action because he or she
engaged in activity protected under the Mine Act, such as making a safety complaint;
| | ----- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (iv) | Temporary Reinstatement Proceedings - a temporary reinstatement proceeding involves cases in which a miner has filed a complaint with MSHA stating that he or she has
suffered discrimination and the miner has lost his or her position;
| | ---- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (v) | Compensation Proceedings - a compensation proceeding may be filed with the Commission by miners entitled to compensation when a mine is closed by certain closure orders
issued by MSHA. The purpose of the proceeding is to determine the amount of compensation if any, due to miners idled by the orders;
| | --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (vi) | Applications for Temporary Relief-applications for temporary relief of any order issued under Section 104; and
| | ---- | --------------------------------------------------------------------------------------------------------------

| | (vii) | Appeals.
| | ----- | --------