Alumina said the pro-rate entitlement offer would be fully underwritten at $3.00 a share.
The company's share price closed down 10 cents to $4.35 on Monday.
The offer is to be conducted in two tranches: an institutional entitlement offer, which Alumina expects to raise about $592 million; and a retail entitlement offer, which it expects to raise about $318 million.
Eligible shareholders, as of Friday, August 29, will have the chance to buy five new ordinary shares for every 19 existing ordinary shares.
The proceeds will be used to fund Alumina's share of additional investment in Alcoa World Alumina & Chemicals' (AWAC) projects in Brazil.
Alumina holds a 40 stake in AWAC, the world's largest alumina business.
"We are investing in additional capacity at a time of unprecedented global demand for alumina and aluminium," Alumina chief executive John Bevan said on Monday in a statement.
"Investing in high-quality, long-life assets is increasingly important to meet the continued growth in demand from our customers and enhance our competitive position."
Alumina said the proceeds would also be used to strengthen its balance sheet so that the company is capitalised for the needs of the business including increased working capital.
"The entitlement offer will also replace funds that would otherwise have been raised by underwriting the dividend reinvestment plan (DRP) for the 2008 interim dividend," the company said.
"Alumina does not intend to underwrite the DRP for the 2008 final dividend.
"Importantly, the structure of the entitlement offer means eligible shareholders have the opportunity to maintain an undiluted interest in Alumina."
Shares in the company will remain in a trading halt until September 1.
