The images, taken last month by a local resident and verified by AFP, are from the same province on Borneo island where Indonesia is building its new capital, a project environmentalists fear will endanger animal habitats in Asia's last great rainforest.

Indonesia has one of the world's highest deforestation rates, with commodities mining a key driver, but it is also one of only two places in the world where orangutans are still found, along with Malaysia.

The footage, which went viral on social media, shows the male orangutan roaming across a chasm of sand streaked with white and black rocks, dug into land still surrounded by vegetation.

"Humans are sometimes too greedy. I hope God won't punish us," read one comment on the video, which racked up tens of thousands of views across YouTube and TikTok.

Locals standing on a bluff overlooking the site filmed the creature as it meandered meters from a digger that was seemingly oblivious to its presence.

Ahmad Baihaqi, who filmed the images, said a group of locals had been watching activity at the mine site when they spotted the primate.

"I felt bad because he looked so confused," the 22-year-old driver told AFP.

"He was alone and looked lost, he didn't know where to go because the forest was disappearing."

The sighting took place in East Kalimantan, where Indonesia is building its multi-billion-dollar capital city Nusantara at breakneck speed.

Habitat disturbed

Although the coal mine is a nine-hour drive from the construction site, the images renewed doubts about government claims that economic activity in the province is not affecting endangered animals.

Local environmentalist Mappaselle of the Balikpapan Coastal Working Group said the footage was clear evidence of that impact.

The orangutan sighting "was definitely because their habitat has been disturbed and is getting smaller," he said.

"Our endangered wildlife could go extinct," he warned.

"It's a natural wealth from God to us on Earth. If wildlife goes extinct, humans have failed in our job to protect nature."

All three species of orangutan are considered critically endangered, though estimates of the number left in the wild vary considerably.

Ari Wibawanto, head of the local conservation agency which sits under the environment ministry, told AFP its officials had located the 15-year-old wild orangutan and moved it to a protected forest area after the footage surfaced.

But he argued that it was natural for male orangutans to roam around.

"The area is not just a mining area, there's also a farm and residential area, and we found the orangutan on someone's farm," said Ari, shrugging off the concerns raised by environmentalists.

"That's the nature of an adult male animal, he doesn't stay in one place, he wanders."

AFP identified the site as belonging to private coal-mining firm Kaltim Prima Coal (KPC), a subsidiary of Bumi Resources, Indonesia's biggest thermal coal producer.

The Environment Ministry and Kaltim Prima Coal did not immediately respond to an AFP request for comment.

Baihaqi said he hoped the striking images would help people think about the costs of environmental destruction.

"I hope we can rehabilitate our forests, or at least protect our wildlife," he told AFP.

"This animal is almost extinct, you rarely can see it anymore."