N.Korea's "socialist utopia" needs mass labour. A growing market economy threatens that

* North Korea building major economic hub near sacred Mount Paektu

* State media lauds thousands of students providing labour in Samjiyon

* Mobilisations of mass labour threatened as people want economic stability - defectors, activists

By Hyonhee Shin

SEOUL, Feb 18 (Reuters) - In January, thousands of North Korean students travelled to Mount Paektu, a sacred mountain where the ruling family claims its roots and where leader Kim Jong Un is building a massive economic hub at the alpine town of Samjiyon.

It is one of the largest construction initiatives Kim has launched, part of his campaign for a "self-reliant economy" even as he seeks to convince U.S. President Donald Trump to lift economic sanctions at their second summit later this month.

State media painted an inspiring picture of patriotic students braving harsh weather, eating frozen rice, and ignoring supervisors' worries about their health in order to work harder on the huge building site.

Kim has visited Samjiyon, near the Chinese border, at least five times for inspections over the past year.

He envisages a "socialist utopia" with new apartments, hotels, a ski resort and commercial, cultural and medical facilities by late 2020, barely four years after Kim ordered modernisation of the "sacred land of the revolution".

North Korean defectors and human rights activists say such mass mobilisations amount to "slave labour" disguised as loyalty to Kim and the ruling Workers' Party. Young workers get no pay, poor food and are forced to work more than 12 hours a day for up to 10 years in return for better chances to enter a university or join the all powerful Workers' Party.

But as private markets boom and more people cherish financial stability above political standing, the regime has been struggling to recruit the young labourers in recent years, they say.

"Nobody would go there if not for a party membership or education, which helps you land a better job. But these days, you can make a lot more money from the markets," said Cho Chung-hui, a defector and former labourer.

"Loyalty is the bedrock of the brigades but what do you expect from people who know the taste of money?"

'BOILING BLOOD OF YOUTH'

Last year, after declaring his nuclear weapons programme complete, Kim shifted his focus towards the economy, saying people's well-being was a top priority.

Samjiyon is at the centre of his new economic initiative, touted as what would be a "model of modern mountainous city to be the envy of the world," alongside an ongoing project to create a tourist hotspot in the coastal city of Wonsan. http://fingfx.thomsonreuters.com/gfx/rngs/NORTHKOREA-TOURISM/0100516J2NK/index.html