A Chinese contractor working on the Laos section of the Kunming-Vientiane railway broke through on a 9-km-long tunnel on Sunday, 21 June in Laos’ mountainous Oudomxay Province.
China Railway Guangzhou Engineering Group drilled 9,296 metres through four fault zones for the Ban Nakok Tunnel, which state news agency Xinhua said brought "huge difficulties" for the project.
The company started drilling in May 2017, and deployed "scientific and technological innovations" to overcome the difficulties, Xinhua said, without providing detail.
An even longer tunnel, 15.2km in length and located on the Chinese side of the border in Yunnan Province, was completed on 24 May by China Railway 17th Bureau Group Co.
The electrified 414-km railway in Laos will run from the Boten border station in the north of the country to the capital, Vientiane, with freight and passenger trains traveling at 160 km/hour.
The Ban Nakok Tunnel is near the Chinese border, some 400km north of Vientiane.
Construction of the Kunming-Vientiane railway began in December 2016 and is scheduled to start operating in December 2021.
The mountainous terrain of Laos means that more than 62% of the total length will comprise bridges and tunnels.
The Laos railway is part of China’s long-term plan for a rail link all the way through Thailand to Singapore.
When construction started at the end of 2016, state media said its cost would be $5.76bn.
According to the International Monetary Fund (IMF), Laos is to contribute $708m to this cost, of which $480m will be borrowed from China.
This was one of the reasons the IMF warned that Laos "faces a high risk of debt distress".
Laos’ GDP is just $20bn, compared to neighbouring Vietnam’s GDP of $255bn.
Image: The Ban Nakok Tunnel is in Laos’ mountainous Oudomxay Province (Luisah/Public domain)