Exhibit 8.1

List of subsidiary companies

At 31 December 2016

The principal operating subsidiary companies of the Rio Tinto Group are listed in Note 33 to the2016 Financial statements. The principal intermediate
holding companies and group finance companies are as follows:



|                                                     |  |                                                     |  |                                        |     |            |     |  |          |  |     | 
|---------------------------------------------------- |  | --------------------------------------------------- |  | -------------------------------------- | --- | ---------- | --- |  | -------- |  | --- | 
|Company and country                                  |  | Principal                                           |  | Class of                               |     | Proportion |     |  | Group    | 
|of incorporation                                     |  | activities                                          |  | shares held                            |     | of class   |     |  | interest | 
|                                                     |  |                                                     |  |                                        |     | held       |     |  |          | 
|                                                     |  |                                                     |  |                                        |     | %          |     |  | %        | 
|Australia                                            |  |                                                     |  |                                        |     |            |     |  |          |  |     | 
|Australian Coal Holdings Pty. Limited                |  | Holding company                                     |  | AUD A shares                           |     |            | 100 |  |          |  | 100 | 
|Hamersley Holdings Limited                           |  | Holding company                                     |  | AUD A Class Ordinary shares            |     |            | 100 |  |          |  | 100 | 
|North IOC Holdings Pty Ltd                           |  | Holding company                                     |  | AUD Ordinary shares                    |     |            | 100 |  |          |  | 100 | 
|North Limited                                        |  | Holding company                                     |  | AUD Ordinary shares                    |     |            | 100 |  |          |  | 100 | 
|Pacific Aluminium Pty. Limited                       |  | Holding company                                     |  | AUD Ordinary shares                    |     |            | 100 |  |          |  | 100 | 
|Peko-Wallsend Pty Ltd                                |  | Holding company                                     |  | AUD Ordinary shares                    |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Finance Limited                            |  | Finance company                                     |  | AUD Ordinary shares                    |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Finance (USA) Limited                      |  | Finance company                                     |  | AUD Ordinary shares                    |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Investments One Pty Limited                |  | Holding company                                     |  | AUD Ordinary shares                    |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Investments Two Pty Limited                |  | Holding company                                     |  | AUD Ordinary shares                    |     |            | 100 |  |          |  | 100 | 
|Robe River Limited                                   |  | Holding company                                     |  | AUD Ordinary shares                    |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  |                                       
|Bermuda                                              |  |                                                     |  |                                        |     |            |     |  |          |  |     | 
|North IOC (Bermuda) Holdings Limited                 |  | Holding company                                     |  | US$1.00 Ordinary shares                |     |            | 100 |  |          |  | 100 | 
|North IOC (Bermuda) Limited                          |  | Holding company                                     |  | US$1.00 Ordinary shares                |     |            |     |  |          |  |     | 
|                                                     |  |                                                     |  | US$100,000.00 Preferred shares         |     |            | 100 |  |          |  | 100 | 
|                                                     |  | US$143.64 Class A Ordinary shares (US$143.64126903) |  |                                        | 100 |            |     |  | 100      | 
|                                                     |  |                                                     |  |                                        |     |            | 100 |  |          |  | 100 | 
|QIT Madagascar Minerals Ltd.                         |  | Holding company                                     |  | US$1.00 Ordinary shares                |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  |                                       
|Canada                                               |  |                                                     |  |                                        |     |            |     |  |          |  |     | 
|46117 Yukon Inc.                                     |  | Holding company                                     |  | CAD Common shares                      |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | CAD Preferred shares                   |     |            | 100 |  |          |  | 100 | 
|535630 Yukon Inc                                     |  | Holding company                                     |  | CAD Common shares                      |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | CAD Preferred shares                   |     |            | 100 |  |          |  | 100 | 
|7999674 Canada Inc.                                  |  | Holding company                                     |  | CAD Common shares                      |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Canada Inc                                 |  | Holding company                                     |  | CAD Class B shares                     |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | CAD Class C shares                     |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | CAD Class D shares                     |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | CAD Class J shares                     |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | US$ Class K shares                     |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Diamonds and Minerals Canada Holdings Inc. |  | Holding Company                                     |  | CAD Class A shares                     |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | CAD Class B shares                     |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | CAD Class C shares                     |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | CAD Class P1 Preferred shares          |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  |                                       
|Namibia                                              |  |                                                     |  |                                        |     |            |     |  |          |  |     | 
|Skeleton Coast Diamonds Limited                      |  | Holding company                                     |  | NAD 2.00 Ordinary shares               |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  |                                       
|Netherlands                                          |  |                                                     |  |                                        |     |            |     |  |          |  |     | 
|Rio Tinto Eastern Investments B.V.                   |  | Holding company                                     |  | 453.78 Ordinary shares                |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  |                                       
|South Africa                                         |  |                                                     |  |                                        |     |            |     |  |          |  |     | 
|Richards Bay Titanium Holdings (Proprietary) Limited |  | Holding company                                     |  | ZAR1.00 A Ordinary shares              |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | ZAR1.00 B Ordinary shares              |     |            | 100 |  |          |  | 100 | 
|Richards Bay Titanium (Proprietary) Limited          |  | Holding company                                     |  | ZAR 0.01 B Ordinary shares             |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | ZAR0.01 B Preference shares            |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | ZAR0.01 BHP Billiton Preference shares |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  |                                       
|United Kingdom                                       |  |                                                     |  |                                        |     |            |     |  |          |  |     | 
|Rio Tinto European Holdings Limited                  |  | Holding company                                     |  | £1.00 Ordinary shares                  |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Finance plc                                |  | Finance company                                     |  | £1.00 Ordinary shares                  |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | US$1.00 Ordinary shares                |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Finance (USA) plc                          |  | Holding company                                     |  | £1.00 Ordinary shares                  |     |            | 100 |  |          |  | 100 | 
|Rio Tinto International Holdings Limited             |  | Holding company                                     |  | £1.00 Ordinary shares                  |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Namibian Holdings Limited                  |  | Holding company                                     |  | £1.00 Ordinary shares                  |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Overseas Holdings Limited                  |  | Holding company                                     |  | £1.00 Ordinary shares                  |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | US$1.00 Ordinary shares                |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Simfer UK Limited                          |  | Holding company                                     |  | US$1.00 Ordinary shares                |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Western Holdings Limited                   |  | Holding company                                     |  | £1.00 Ordinary shares                  |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | US$1.00 Ordinary shares                |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  |                                       
|United States of America                             |  |                                                     |  |                                        |     |            |     |  |          |  |     | 
|Rio Tinto America Holdings Inc.                      |  | Holding company                                     |  | US$0.01 Class A Common shares          |     |            | 100 |  |          |  | 100 | 
|                                                     |  |                                                     |  | US$100.00 Series A Preferred Stock     |     |            | 100 |  |          |  | 100 | 
|Rio Tinto America Inc.                               |  | Holding company                                     |  | US$100.00 Common shares                |     |            | 100 |  |          |  | 100 | 
|Rio Tinto Minerals Inc.                              |  | Holding company                                     |  | US$0.01 Common shares                  |     |            | 100 |  |          |  | 100 |