An institutional placement raised $285 million, including a $120 million strategic placement to AustralianSuper, and an institutional one-for-one pro-rata accelerated non-renounceable entitlement offer raised $641 million.
The offers were underwritten by Macquarie and Goldman Sachs.
The issue price was $5.40, a 13.2% discount to the company's previous closing price.
"The institutional entitlement offer and placement was very well received and forms an important part of the high-quality funding package we have secured to ensure that we can fully fund the acquisition of this tier one asset, while retaining balance sheet flexibility to deliver our Motheo copper mine in Botswana and our ongoing global exploration program," Sandfire managing director and CEO Karl Simich said.
"Base metal assets which offer this combination of scale, grade, mine life and exploration upside are extremely rare globally.
"The MATSA acquisition transforms Sandfire into a first quartile copper producer of global scale and allows us to leverage our skill set to deliver on our growth ambitions to create one of the highest quality and most compelling copper exposures on the ASX."
An underwritten retail entitlement offer on the same terms will open this Thursday to raise roughly $322 million.
The $1.24 billion proceeds from the raisings will be used alongside a US$650 million syndicated and underwritten facility with Citi, Macquarie, Natixis and Societe Generale secured by MATSA and an existing undrawn A$200 million facility with ANZ, secured by the DeGrussa mine, to complete the $2.57 billion acquisition.
The MATSA mining complex comprises three underground mines, Aguas Tenidas, Sotiel and Magdalena, and a 4.7 million tonne per annum processing plant to produce 100,000-120,000 tonnes of copper equivalent per annum at low C1 costs of just US40-50c per pound of copper due to zinc, lead and silver credits.
The project has a mine life of 12 years with exploration upside and expansion opportunities.
The transaction is set to transform Sandfire into one of Australia's largest copper producers with pro-forma FY22 production of 170,000-194,000tpa of copper equivalent.
Shares in Sandfire fell 12.5% to A$5.44.