Japan's steel giants have been warned they are risking their reputation and an investor backlash by locking in another half-century of Queensland coal.
Almost a third of the Blackwater coal mine in central Queensland will be sold to Nippon Steel and JFE Steel in joint venture deals with Whitehaven Coal announced on Thursday.
Blackwater is one of the largest coal mines in Australia, with a strike length of 80km, and production could extend beyond 50 years with support from the long-term customers.
Shareholder organisation Market Forces said Blackwater carried a costly rehabilitation liability for investors and governments.
"JFE Steel can't say it's serious about climate change being 'critical business', then turn around and buy a stake in a dangerous and polluting coal mine," Market Forces spokesperson Michelle Surowiec said.
"By buying into a company hell-bent on coal expansion, Nippon Steel and JFE Steel risk their reputation and investor backlash over being riddled with greenwash."
Grassroots group Move Beyond Coal said activists dressed as koalas planned to gather at the Japanese firms' Sydney headquarters because coal mining posed an unacceptable threat to the environment, cultural heritage and the global climate.
Nippon Steel was helping drive the koala to extinction by partnering with a company planning to clear thousands of hectares of endangered habitat for new coal mines, campaigner Fahimah Badrulisham said.
Whitehaven said it had a more balanced exposure to metallurgical coal for steelmaking and thermal coal for energy generation after completing the acquisition of the Daunia and Blackwater mines from BHP in April.
The miner said it expected to benefit from global metallurgical coal supply constraints, combined with increased demand from India, that would drive prices higher.
Whitehaven also forecast robust demand for thermal coal in Asia, and for use in general industry.
The separate deals with Nippon Steel (to own 20 per cent) and JFE Steel Corporation (10 per cent) are worth a combined $US1.08 billion ($A1.6 billion), and are expected to complete in the first quarter of 2025, subject to approvals.
Shares in Whitehaven soared almost five per cent to $7.55 in afternoon trade after the deal and latest profit announcement.
Whitehaven reported underlying earnings for the year to June 30 of $1.4 billion, including $272 million from the Daunia and Blackwater mines.
The underlying net profit of $740 million for the year was before $385 million in acquisition expenses, while the statutory net profit fell to $355 million from $2.67 billion.
"While we have been growing the business, we have maintained focus on the NSW operations to deliver a solid financial result for FY24," Whitehaven chief executive Paul Flynn said, citing cost pressures from labour, electricity and equipment parts.
Despite lower coal prices, he said Whitehaven was well positioned to continue to deliver strong returns for shareholders, from metallurgical and thermal coal production.
Whitehaven said development projects included the Vickery project in north-west NSW, Winchester South in Queensland adjacent to the recently acquired Daunia mine, and the Narrabri extension project in NSW.
The Narrabri underground mine project, which has state consent, would extend the approved life of the mine from 2031 to 2044 but needs federal approval.
The process for obtaining government and regulatory approvals for coal mining projects was subject to "ever-increasing difficulty and legal challenges" which added to costs and risks, Whitehaven said.
Whitehaven declared a fully franked final dividend of 13 cents per share.
