By Justin Rowlatt
BBC News, India
India's booming economy means a growing demand for the resources and raw materials which feed its factories, but one indigenous community under threat is determined to protect its way of life.
The ceremony began when the shaman came staggering out of his hut.
He had splashes of fresh blood daubed on his face and stared blindly as he began a shuffling, swaying dance to the rhythm of the drums.
After a few moments the first woman fell to the ground.
The Dongria's sacred mountain is rich in bauxite
She seemed to be having some kind of fit.
I watched in the flickering firelight as she jerked spastically on the ground, her legs twisted at an improbable angle underneath her.
Seconds later she lurched up to her feet and, bent double at the waist, she began to sway, her feet stamping in rough time, her long black hair hanging down over her head and face.
Soon eight people had joined in, all bent over, all apparently also in a deep trance.
The witchdoctor took up two fierce-looking, long, curved swords which he waved around in front of him.
This was becoming genuinely frightening.
We were in an isolated forest clearing deep in the hills of the Indian state of Orissa.
I turned towards Lado, the village headman.
I was surprised to see he was smiling broadly.
He was clearly thoroughly enjoying the festivities - and, I suspected, my discomfiture too.
"They have been possessed by gods," he explained, "maybe the god of the Earth, of the forest or Niyam Raja, the god of our mountain.
"Whatever they do now is not them, it is the play of the gods."
I was here because the traditional way of life of the Dongria tribe has come crashing up against modern India's seemingly insatiable appetite for resources.
A refinery has already been built to process ore from the planned mine
Niyamgiri, the mountain the Dongria people worship and whose spirit possessed the dancers, contains an incredibly rich seam of bauxite, the ore from which aluminium is made.
According to some estimates, the bauxite in Niyamgiri mountain could be worth more than $2bn (£1.25bn).
The scale of the threat became apparent when Lado led me on an exhausting five-hour trek over the mountain.
He wanted to show me the $1bn aluminium processing plant built way down in the valley, by a UK-based multinational called Vedanta.
Lado described how, a couple of years ago, one of the vice-presidents of Vedanta had come to the village and had offered to pour money into the community, if they would support mining the bauxite in Niyamgiri mountain.
Lado said he had told the company's men: "We don't need your schools, we don't need your houses and we don't need your road."
When they tried to take photos, he threatened to smash their cameras.
"They left pretty soon after that," Lado told me with a grin.
Lado is an easy man to like and it was hard not to enjoy the pride he felt having seen off the representatives of this powerful multinational.
But, in my experience, the apparently inexorable power of money and modernisation almost always wins out against the claims of indigenous people.
Nevertheless, as Lado and I talked, I had a sneaking suspicion that the Dongria might be an exception to the rule.
When the aluminium plant was built, it seemed mining the bauxite in Niyamgiri mountain was a done deal.
The government of Orissa signed a memorandum of understanding giving permission, and the Indian government assured Vedanta that its vast investment here would be secure.
Then Lado and his fellow tribespeople began their campaign - and managed to get support from around the world.
Soon Vedanta's investment began to seem a lot less safe.
Last year, the tribe won an important victory, when the Indian environment minister ruled that no mining could take place on Niyamgiri mountain.
Vedanta is now challenging that decision in India's Supreme Court.
I was keen to hear the company's side of the story and Vedanta had agreed to an interview but, when they spotted us in town talking with Lado and some other tribal people, they called it off.
"It is so difficult for us to get our message across," Tony, Vedanta's spokesman said plaintively, as he explained why the company had changed its mind.
I could understand his frustration.
Here in Lanjigarh, Vedanta has built schools and roads and a modern hospital.
It has also created 1,500 jobs.
There is no doubt that allowing mining on Niyamgiri mountain would generate a lot more money for people here, but there is also no question that the Dongria have a very strong claim to the land.
The problem is that mining the bauxite here would destroy not just the land the Dongria have lived on for centuries - quite possibly millennia - but also their god.
I felt rather sorry for Tony and Vedanta.
It is very hard to justify destroying someone's god, however compelling your case.
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