China finished construction last month on the tunnel under the Amur River on the Russian-Chinese border.
The tunnel was constructed to accommodate an extension of a pipeline intended to pump millions of tons a year of Russian oil across to China.
More than 80 Chinese workers were involved in the drilling of the 1,900m tunnel since last September.
Russia and China signed a cooperation deal on the construction of a branch of the Eastern Siberia-Pacific Ocean pipeline (ESPO) toward China in February 2009. A deal was also signed for long-term Russian old supplies to China.
The branch, which runs from Skovorodino in the far east of Russia to Daqing in the northeast of China, is scheduled to be operational next year.
The construction cost of the branch is estimated at 11-12bn rubles
Russian officials earlier said the construction cost of the branch had been estimated at RUB 11-12bn (USD 377M – 410M), while the annual revenues from oil sales to China could reach RUB 57bn (USD 1.9bn).
Russia is scheduled to export 15 million tons of crude oil to China annually over the next 20 years.
