Abstract: A lead−zinc mine back-mining project and a pioneering project are now facing a gradual shift to the deep earth, facing the special conditions of over 1 000 metres deep and high ground pressure for the construction of the underground return air system. The construction mainly includes three vertical shafts in the middle section of −1106 m, middle section of −1 046 m, and middle section of −1 276 m below the relative 0 elevation of the surface wellhead. The construction of the shafts was carried out using a backhoe drilling rig to form a small section of 2 m in diameter and then combined with the high-shaft brushing and reaming technique to ream the shafts to a large section of 4 m in accordance with the design requirements for the return air. The supporting works for the shafts included the construction of winch chambers and selection of equipment for the stranding system, and during the construction process, the shafts were evaluated by stress assessment using Flac^3D, and reinforcement support was carried out on the stress-concentrated portions of the shafts. Through the above theoretical calculations, process technology, and supporting equipment, the successful application of reaming construction technology in high shaft with high ground pressure for kilometre depth in the lead−zinc mine has provided a technical theory and practical basis for the large cross-section hole reaming construction in deep-earth high shaft in China.