Workers began digging a tunnel through a snow-covered mountain in Tibet Autonomous Region on Tuesday, marking the resumption of a road construction project for China's last road-less county.

A team of several hundred experienced technical staff dispatched from an armed police unit were boring a 3.3-km tunnel through the Galung La mountain, which has an average altitude of about 5,000 meters in Tibet's Nyingchi Prefecture, team leader Liu Genshui said.

More than 20 advanced pieces of machinery were being used to dig the tunnel, part of the 117-km highway project.

"The tunnel construction is the most difficult phase for building a highway to Medog County," he said. "But we will try to finish the project as soon as possible."

Situated at Tibet's border with India and nestled among snow-capped mountains, Medog is the last of the country's 2,100 counties to be connected via a highway.

The construction poses a number of engineering challenges as the county sits on the Himalayan fault line where there are many earthquakes and landslides, experts said.

Chinese authorities have been considering building a highway to Medog since 1961, but the project had been suspended several times due to tough geological conditions and poor technology. In 1994, a highway was finished to reach Medog for the first time but parts of it were soon destroyed by landslides.

Afterwards, authorities continued their construction plan and studied how to build a highway under such complicated geological conditions. The project was put on the agenda of Tibet's 2006-2010 Five-year Plan.

According to the plan, a 142 km barely passable, pot-hole filled road that now connects Medog to the nearby Zhamog Township, the county seat of Bome, will be upgraded to meet the standards of a highway, Liu said.

With the digging of the Galung La tunnel, the Zhamog-Medog highway is expected to shorten the distance by about 25 km.

The highway will be built at a cost of 950 million yuan (US$138.6 million), he added.

The sparsely populated Medog, which means "flower" in the Tibetan language, has only about 10,000 inhabitants, mostly in rural areas. The per capita annual income of the locals was about 2,400 yuan last year, local government statistics show.

(Xinhua News Agency September 17, 2008)