UPDATE 1-Australia's Alumina to raise $730 mln in new equity

* 7-for-10 rights issue at A$1 per share * Offer at 32.9 pct discount to Wednesday closing share price * $460 mln to be raised through institutional offer (Adds detail) SYDNEY, April 30 (Reuters) - Australian-listed Alumina Ltd (AWC.AX: Quote, Profile, Research), the world's largest supplier of alumina to the aluminium industry, plans to raise about A$1.02 billion ($730 million) in new shares to help cut debt, it said on Thursday. Alumina is a 40 percent partner in the Alcoa World Alumina and Chemicals joint venture. U.S. aluminium giant Alcoa (AA.N: Quote, Profile, Research) holds 60 percent. Alumina is raising the funds through a 7-for-10 rights issue at A$1 per share, including institutional and retail offers. It said it would use the new funds to repay debt and strengthen its balance sheet. The offer represents a 32.9 percent discount to Alumina's closing price on Wednesday of A$1.49 per share. Alcoa said it has also rolled over $100 million of debt facilities to April 2012 that were previously due to mature in 2010. The company said the AWAC joint venture was responding to deteriorating market conditions by conserving cash.