Meridian Energy has resolved its negotiations with Rio Tinto subsidiary New Zealand Aluminium Smelters locking in the Tiwai smelter until at least January 2017 - with the help of a $30 million subsidy from the New Zealand government. The deal, which has been a year in the making, will help clear the way for Meridian's $5 billion float on the stock exchange - expected to go ahead before the end of the year.