A 5.48m diameter CREC R277 hard rock TBM developed by China Railway Engineering Equipment Group Co., Ltd. (CREG) has completed the first section of Hubei Maping Phosphate Mine 2# Air Return Inclined Shaft Project in China. The event marks the first successful application of a TBM in the inclined shaft construction of non-coal mines and is of great significance to the safe and efficient downhill tunnelling of long-distance and large-slope mine inclined shafts.
The section 1 of the project is 2311.7m long with the maximum longitudinal slope of -15% and the minimum curve radius of 480m. During construction, the TBM had to overcome a series of challenges such as a crown collapse in an unfavorable geological section, water ingress, and water leakage backflowing to the front of the TBM from the gantry area.
The CREC R277 is equipped with an advanced geological prediction system to achieve the precise identification of geology in front of tunnel face, and innovatively applies synchronous excavation chamber dewatering technology during the large-slope downhill tunnelling. The TBM has set records with a maximum daily advance of 29.2m in the straight section and 25m in the curved section thus far.