ex12d10tr1major

TR-1: Standard form for notification of major holdings NOTIFICATION OF MAJOR HOLDINGS (to be sent to the relevant issuer and to the FCA in Microsoft Word format if possible)i 1a. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attachedii: Rio Tinto PLC 1b. Please indicate if the issuer is a non-UK issuer (please mark with an “X” if appropriate) Non-UK issuer 2. Reason for the notification (please mark the appropriate box or boxes with an “X”) An acquisition or disposal of voting rights X An acquisition or disposal of financial instruments An event changing the breakdown of voting rights Other (please specify)iii: 3. Details of person subject to the notification obligationiv Name AustralianSuper Pty Ltd City and country of registered office (if applicable) Melbourne, Australia 4. Full name of shareholder(s) (if different from 3.)v Name JPMorgan Nominees Australia Ltd City and country of registered office (if applicable) Sydney, Australia 5. Date on which the threshold was crossed or reachedvi: 07/10/2025 6. Date on which issuer notified (DD/MM/YYYY): 09/10/2025 7. Total positions of person(s) subject to the notification obligation % of voting rights attached to shares (total of 8. A) % of voting rights through financial instruments (total of 8.B 1 + 8.B 2) Total of both in % (8.A + 8.B) Total number of voting rights held in issuervii Resulting situation on the date on which threshold was crossed or reached 4.014773% 4.014773% 50,351,535 Position of previous notification (if applicable) 3.009337% 3.009337% 37,704,651 EXHIBIT 99.12

Notice to ASX/LSE 8. Notified details of the resulting situation on the date on which the threshold was crossed or reachedviii A: Voting rights attached to shares Class/type of shares ISIN code (if possible) Number of voting rightsix % of voting rights Direct (DTR5.1) Indirect (DTR5.2.1) Direct (DTR5.1) Indirect (DTR5.2.1) Equity: GB0007188757 50,189,289 NIL 4.00183% NIL ADR: US7672041008 162,246 NIL 0.01293% NIL SUBTOTAL 8. A 50,351,535 4.01476% B 1: Financial Instruments according to DTR5.3.1R (1) (a) Type of financial instrument Expiration datex Exercise/ Conversion Periodxi Number of voting rights that may be acquired if the instrument is exercised/converted. % of voting rights SUBTOTAL 8. B 1 B 2: Financial Instruments with similar economic effect according to DTR5.3.1R (1) (b) Type of financial instrument Expiration datex Exercise/ Conversion Period xi Physical or cash settlementxii Number of voting rights % of voting rights SUBTOTAL 8.B.2

Notice to ASX/LSE 9. Information in relation to the person subject to the notification obligation (please mark the applicable box with an “X”) Person subject to the notification obligation is not controlled by any natural person or legal entity and does not control any other undertaking(s) holding directly or indirectly an interest in the (underlying) issuerxiii X Full chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held starting with the ultimate controlling natural person or legal entityxiv (please add additional rows as necessary) Namexv % of voting rights if it equals or is higher than the notifiable threshold % of voting rights through financial instruments if it equals or is higher than the notifiable threshold Total of both if it equals or is higher than the notifiable threshold 10. In case of proxy voting, please identify: Name of the proxy holder The number and % of voting rights held The date until which the voting rights will be held 11. Additional informationxvi Place of completion Melbourne Date of completion 09/10/2025

Notice to ASX/LSE LEI: 213800YOEO5OQ72G2R82 Classification: 2.3: Major shareholding notifications Contacts Please direct all enquiries to media.enquiries@riotinto.com 0BMedia Relations, 1BUnited Kingdom Matthew Klar M +44 7796 630 637 David Outhwaite M +44 7787 597 493 2BMedia Relations, 3BAustralia Matt Chambers M +61 433 525 739 Bruce Tobin  M +61 419 103 454 Rachel Pupazzoni M +61 438 875 469 4BMedia Relations, 5BCanada Simon Letendre M +1 514 796 4973 Malika Cherry M +1 418 592 7293 Vanessa Damha M +1 514 715 2152 6BInvestor Relations, 7BUnited Kingdom Rachel Arellano M: +44 7584 609 644 David Ovington M +44 7920 010 978 Laura Brooks M +44 7826 942 797 Weiwei Hu M +44 7825 907 230 8BInvestor Relations, 9BAustralia Tom Gallop M +61 439 353 948 Phoebe Lee M +61 413 557 780 10BMedia Relations, 11BUS and Latin America Jesse Riseborough M +1 202 394 9480 12BRio Tinto plc 6 St James’s Square London SW1Y 4AD United Kingdom T +44 20 7781 2000 Registered in England No. 719885 13BRio Tinto Limited Level 43, 120 Collins Street Melbourne 3000 Australia T +61 3 9283 3333 Registered in Australia ABN 96 004 458 404 This announcement is authorised for release to the market by Andy Hodges, Rio Tinto’s Group Company Secretary.

Notice to ASX/LSE riotinto.com