People's Daily Online report excavation official started on May 19. For longest tunnel under Yangtze River.

Tunnel Boring Machine use for excavation. Total length tunnel is 10.226 kilometer, excavation diameter is 7.95 meter, inner diameter of tunnel is 6.8 meters, and diameter is 7.6 meter.

After excavation finish, pipes is going laid in tunnel. Tunnel for natural gas transportation from Russia.

http://finance.people.com.cn/BIG5/n1/2021/0519/c1004-32107467.html