Deformation Detection and Structural Failure Mechanism of Large Mine Chutes: A Three-Chute Case Study at an Iron Mine

To examine the deformation behavior and failure mechanisms of large-scale mine chutes under complex service conditions, we performed multiple C-ALS three-dimensional laser scanning surveys on the 1#, 2# and 3# chutes at an iron mine in Anhui Province. The results showed that all three chutes had severe non-uniform expansion, with maximum diameters of 12.2 m, 14.8 m and 16.9 m, respectively. The maximum annual wear rates during the detection period were 2.4 m, 6.0 m and 2.5 m, respectively. The failure of the chutes was mainly caused by local block collapse drops, influenced by the joints and fissures of the surrounding rock, and the wear showed significant discontinuous and non-uniform characteristics. Based on the detection data, a three-peak Gaussian model is established to describe the nonlinear distribution of the expansion along depth, with peak centers located at −462 m, −497 m and −520 m. By comparing linear and exponential models, it is determined that the expansion exhibits a linear evolution trend with time. Based on the maximum diameter and annual wear rate, we estimate the remaining safe service life of each chute, and provide the confidence interval for the expansion value at a 90% confidence level (such as [1.31 m, 4.83 m] at −520 m). Research shows that high-precision 3D laser scanning can effectively reveal the deformation and evolution laws inside the chute. It is recommended to immediately take reinforcement measures for chute 2 and establish a dynamic monitoring system for the common weak zone between −480 m and −520 m. Research on the evolution of surrounding rock fractures should be carried out to provide a scientific basis for chute life assessment and risk control.