Police in Papua New Guinea are investigating an attack by 100 armed local landowners on three Chinese workers at the Ramu nickel mine in Madang province.
The workers from China's state-owned Metallurgical Construction Company are now recovering in Madang's General Hospital.
It is unclear what provoked the incident but the company is reported to have evacuated its other Chinese workers amid fears of more attacks.
The incident comes amid claims by locals that they were not consulted about the project and have been left out of royalty deals.
As well as environmental concerns, the PNG government has been accused of breaking the country's own laws by allowing mining work to go ahead, despite an ongoing dispute among local landowners about who has traditional ownership of the site.
The mine also will pump 100 million tonnes of waste slurry into the province's pristine Astrolabe Bay during the next 20 years.