Image caption Campaigners and researchers say that mining operations have gathered apace in recent years

A record number of Tibetans have been displaced in their own homeland amid rampant mining and river damming in vacated areas, according to reports.

Tibetan leaders and researchers claim that this displacement has been going on over the last few years under China's nature conservation policy.

The allegation comes at a time when the figure for Tibetans reaching other countries as refugees has been falling.

Chinese authorities did not respond to requests for comment by the BBC.

However, China's government has previously issued strong denials that forced evictions are used in the relocation of Tibetan pastoralists.

Tibetan officials in Dharamashala, India, which hosts the office of Tibet's exiled spiritual leader, the Dalai Lama, say that between 1.5 and two million Tibetan pastoralists have been forcibly displaced from their pastoral lands, while mines for gold and copper ore extraction have been mushrooming.

They say most of the displaced people are not happy and of the more than 130 self-immolations by Tibetans since 2008, about 20 were by members of the nomadic community who were forced to leave their pastoral lands.

'Land grab'

What you are seeing is that these Tibetans are being removed so that their age-old pastoral lands can be rampantly mined Jigme Norbu, Tibet researcher

"Tibetans who have come from [the region] as refugees have told us that they have seen for themselves how their pasture land is illegally grabbed and then mined for mineral resources," said Tenzin Norbu, who heads the environmental desk at the Central Tibetan Administration office in Dharamashala.

"They told us that Chinese authorities warned [via loudspeaker from a vehicle] that anyone who protested against mining would be seen as protesting against the state because China needs natural resources to develop.

"These people who managed to flee Tibet also said that Chinese officials went to each house and made them sign papers that they would not protest if there were mining activities."

Researcher Jigme Norbu, who studies Tibetan nomads with the Central Tibetan Administration, said of the nearly 40 Tibetan refugees who had arrived at the Dalai Lama's office at Dharamashala in 2012, most of them were pastoralists.

Image caption Tibet's spiritual leader, the Dalai Lama, has been in exile since 1959

The number of Tibetan refugees reaching India through Nepal - which borders Tibet - used to be around 1,000 every year until 2008 when restrictions on their movement were tightened, said Jigme.

"The Chinese government says the pastoralists are being resettled mainly to conserve the grassland that it claims is being degraded because of unsustainable pastoral practices," he added.

"But what you are seeing is that these Tibetans are being removed so that their age-old pastoral lands can be rampantly mined and that actually has led to huge environmental destruction."

Tibetan leaders and experts in exile say the damming of rivers to power processing works in large scale mines has exacerbated the problem.

"When hydropower plants are built in such area, Tibetans who have fled and reached us said, more private investors pour in to mine precious minerals like gold, silver and copper ore," said Jigme Norbu.

Pollution threat

In area after area where China has officially proclaimed the depopulated zones to be national parks, protected areas, nature reserves, in reality, mines are popping up Gabriel Lafitte, Author on Tibet

According to cables released by Wikileaks, the Dalai Lama told the US ambassador to India in 2009 that the focus of international community should be on environmental issues in Tibet for the next 5-10 years, rather than the political situation.

"Melting glaciers, deforestation and increasingly polluted water from mining were problems that cannot wait, but the Tibetans could wait five to 10 years for a political solution," he was reported as saying.

And in September, a report in the Tibet Post International, which was founded by exiles, suggested the Chinese military had staged a crackdown on Tibetans who were protesting against gold mining in Yulshul County. eastern Tibet.

Although no official records are available, researchers with the Central Tibetan Administration office say the number of mining sites has reached nearly 240 and that most of them are in the pastoral areas that were once home to nomads.

They also say many of the mines are near the headwaters of Asia's big rivers like Yangtze, Yellow and Mekong which means their waters could run the risk of being polluted.

Image caption Earlier this year, a landslide at a mine east of Lhasa buried 83 workers

Nearly half of the six million-strong Tibetan population is estimated to belong to a nomadic community.

Experts say the Chinese authorities adopted the idea of moving pastoral communities in the early 2000s but that most of the displacement and the mining activity gained pace only in the last few years.

"It has been a silent crisis," says Gabriel Lafitte, who has researched and written about Tibet for nearly 40 years.

"In area after area where China has officially proclaimed the depopulated zones to be national parks, protected areas, nature reserves, in reality, mines are popping up.

"You can't have a mine operating in an area that is meant to be exclusively reserved for rehabilitation of a degraded rangeland."

Lafitte said the Tibetan nomads had demonstrated 9,000 years of successful land use, whereas Beijing took them as backward, illiterate people who had no care for the land.

Long traditions

Some Chinese academics have also expressed reservation on the removal of pastoralists from their native lands.

"There is a need for the re-recognition of the uniqueness of traditional pastoralism and its institutional arrangements," wrote Wenjun Li of Peking University's department of environmental management in a paper she co-authored.

"The culture of traditional pastoralism has resulted from a long-term interaction with local dynamic ecosystems and social organisations.

"This pastoral culture and traditional knowledge play a crucial role in how herders develop their institutions, their livestock production practices and their use of grassland resources.

"Rangeland policies that 'reform' pastoral society have simultaneously weakened pastoral culture and customs, and changed traditional pastoral living styles."

The briefing paper published by the International Institute for Environment and Development last April, however, does not mention mining.

A report on the relocation of Tibetan pastoralists by Human Rights Watch (HRW) published in June this year said: "Tibetans coming from both farming and nomadic herding communities who were interviewed said that large numbers of people relocated or re-housed did not do so voluntarily and that they were never consulted or offered alternatives.

"While some Tibetans have genuinely welcomed aspects of the housing policies and have benefited from them, many are concerned about their ability to maintain their livelihood over time.

"The Chinese government strongly denies any forced evictions take place in the relocation and re-housing operations."

China's Tibet Autonomous Region officials and its National Development and Reform Commission were not available for comment.