On January 23, the "Jiangtong No. 1", China's first ultra-small turning radius hard rock tunnel boring machine (TBM) for non-ferrous metal mines, independently developed by China Railway Engineering Equipment Group (CREG), successfully completed a 3,050-meter tunneling task in the lead-zinc-silver mine project in the Yinzhu Mountain mining area of Guixi City, Jiangxi Province, marking the first successful application of an ultra-small turning radius TBM in China's non-ferrous metal mining sector.

The "Jiangtong No. 1" TBM has an excavation diameter of 3.53 meters and an overall length of approximately 64 meters. The equipment was tailor-made for the haulage roadway of the Yinzhu Mountain mining area in Jiangxi, integrating tunneling, support, mucking, and transport functions. With superior performance, it significantly improved roadway construction quality, reduced rock disturbance from cavern excavation, further lowered construction risks, improved the construction environment, and ensured roadway tunneling safety. Since launch, the "Jiangtong No. 1" TBM has successfully completed three turns with a radius of R30 meters, achieving a maximum monthly advance of 430 meters and a maximum daily advance of 28 meters.

The tunneling geological conditions of the lead-zinc-silver mine project in the Yinzhu Mountain mining area are complex, with fractured zones and faults totaling nearly 1,000 meters in length. Among them, the cross-middle-section inclined ramp from -190 to -140 has a total length of 584 meters, with fractured zones accounting for 40 percent. There is a 187° switchback curve with an ultra-small turning radius, and the ramp is designed with a gradient of 10.56%. Constrained by factors such as the ramp gradient and ultra-small turning radius, the equipment's original mucking system could hardly meet construction requirements, greatly affecting tunneling efficiency. After in-depth research and verification, the project team adopted a scheme using an ultra-small turning radius continuous belt conveyor for mucking, successfully overcoming a series of construction challenges such as "steep uphill slopes, switchback curves, and fractured zones," providing strong support for the smooth progress of the project.

The successful application of the "Jiangtong No. 1" TBM not only provided strong support for the development of Yinzhu Mountain Mining, but also laid a solid foundation for CREG to open up new markets, and accumulated valuable experience for the application of ultra-small diameter TBM projects in the non-ferrous metal mining sector.