Australia's South32 on Thursday posted a 55% rise in annual profit, largely in line with market expectations, and extended its shareholder-returns program, sending its shares to a more than four-year high.

Shares of the world's biggest manganese producer rose as much as 2.9% to A$5.29. They were last up 1%.

The miner reported underlying earnings attributable of $1.03-billion for the year ended June 30, up from $666-million in the prior year and just shy of Visible Alpha's consensus estimate of $1.05-billion.

South32 said higher base and precious metals prices, cost management and the restart of its Australia manganese operations boosted its earnings during the period.

"We remain constructive on South32 as a diversified base metals growth vehicle, with disciplined capital management and improving portfolio clarity," said Jefferies, which has a "buy" rating on the stock.

Excluding the aluminium portfolio, copper accounted for more than half of South32's annual earnings, cementing it as the miner's primary cash generator.

"Our focus is on growing the copper and zinc (portfolios). When you see capital allocated, it's certainly going to be in the commodities that align with our strategy," CEO Matt Daley told Reuters in response to a question about whether manganese remained core to its business.

Underlying earnings before interest, taxes, depreciation, and amortisation for the Sierra Gorda copper mine in Chile increased by $276-million to $758-million during the period.

South32 is readying a feasibility study at its Ambler copper joint venture project in Alaska, which it plans to deliver next year. Any eventual copper production is not expected until the middle of the next decade, Daley said.

Its decision to divest most of its aluminium assets to US-listed Alcoa for an implied enterprise value of up to $5.6-billion earlier this year has helped it focus on higher-margin growth assets such as copper mining in Chile and base metals in the US.

South32 also extended its $2.6-billion shareholder returns programme by six months to September 2027, with $209-million still to be returned through special dividends and share buybacks.

It declared a final dividend of 5.4 cents per share for the year ended June 30, higher than 2.6 cents apiece declared last year.

The miner cut its 2027 production forecast to 2.6-million tons to 2 9-million tons of manganese ore from its previous forecast of 3.2-millio tons after its Australian operations resumed following the disruption of Tropical Cyclone Megan.

Daley said South32 has had no problem placing its Australian manganese after last year's shutdown of the Liberty Bell Bay manganese smelter in Tasmania, which it previously supplied and was recently placed into liquidation following its sale to Sanjeev Gupta's Liberty Group in 2021.