Chalco raised alumina prices 5.7 pct on Dec 31

* China's top alumina producer ups spot prices to $410/tonne * Sixth consecutive rise since start of 2009, up 40 pct BEIJING, Jan 4 (Reuters) - Aluminium Corp of China Ltd (Chalco) raised spot alumina prices by 5.7 percent to 2,800 yuan ($410.1) per tonne from Dec. 31, the first rise since Sept. 30, according to its website (www.chalco.com.cn). Chalco, the country's top aluminium firm and the world's third-largest alumina producer, raised alumina prices steadily throughout 2009 from a low of 2,000 yuan. Prices had halved in the second half of 2008 from 4,200 yuan per tonne. Chalco had shut 4.11 million tonnes of its 11 million tonne alumina capacity due to the economic downturn which crippled demand for the metal, but it has restarted all its plants, a company executive told Reuters on Dec. 14. Chinese aluminium smelters have already agreed to pay higher term prices for imported alumina in 2010. They will pay 14.5-15 percent of prices for aluminium on the London Metal Exchange, up from 13.5-14 percent last year. That formula puts term alumina prices at around $330 per tonne on a free-on-board basis, based on Monday's aluminium prices. Chalco's prices for term alumina are set at 17 percent of Shanghai Futures Exchange aluminium prices in 2010, compared with 15-18 percent in the last three years, smelter officials have said. ($1=6.827 YUAN) (Reporting by Tom Miles; Editing by Jacqueline Wong)