A TBM has broken through on the final rock face to complete excavation of a lithium ore transport tunnel in Chijiaoshan in Hunan.
TBM Longyuan drilled the 7.3km tunnel through complex geology in the Nanling Mountains.
China Railway Engineering Equipment Group (CREG) says Longyuan is the world’s first TBM purpose-built for lithium mining. With a diameter of 6.3m and a total length of 155m, it was designed to handle hard rock and challenging geological transitions.
The entire route was excavated uphill at an average gradient of 5.7%. The TBM was equipped with a wear-resistant cutterhead, steel arch erector, rock bolt drill, and systems for floor preparation, side cutting, shotcreting, and material transport – enabling continuous, fully mechanised operations.
Compared to traditional drill-and-blast methods, the TBM significantly improved excavation efficiency and shortened the construction timeline. In September last year the project reached a record monthly advance of 1,186m, which CREG says set a new global benchmark for hard rock mining tunnels.
Originally scheduled for completion by the end of August 2025, the tunnel was successfully delivered three months ahead of schedule.
