Nine months ago commentators at China's official Xinhua news agency were rueing Rio Tinto's “perfidy” in “kicking down the ladder”. Now the Anglo-Australian miner is repairing ties with state-owned Chinalco, the suitor it spurned, by handing it a share of the spoils in the Simandou iron ore project in Guinea, reputed to be the world's third-best deposit.

There are no numbers yet, but this seems a smart move. If Rio needs a fresh start anywhere, it's in Guinea, where it has been accused of under-investment and stripped of half its licences. More civilised relations with Chinalco could also pay dividends ahead of the trial of Stern Hu, Rio's former top executive in the country, and as Mofcom, China's competition authority, is weighing objections to Rio's planned iron ore joint venture with BHP Billiton. Even without all that, however, Rio has some making up to do to its largest shareholder. Chinalco's original 2008 investment strengthened the company's defence against the hostile approach from BHP. The promise of a huge investment last year also allowed debt-laden Rio to rent China's balance sheet during a time of maximum turmoil. Chinalco, for its part, did not attempt low-ball valuations of assets. If it was guilty of anything, it was over-ambition.

Finally, a deal could alleviate pressure from the Chinese company for board representation. During last year's talks, Chinalco was willing to compromise on stakes in assets and on the terms of a convertible bond, but the requirement of two board seats in perpetuity seemed non- negotiable. Having won control over its destiny by pursuing a rights issue and the JV with BHP, Rio should be determined to keep representatives of its largest customer nation out of the boardroom. Selective invitations to co-invest could be a compromise the group can live with.