Centrifugal modeling test of large hexagonal drift under backfill body
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Abstract:
Jinchuan Nickel Mine is the most important nickel ore resource base in China. The small-section hexagonal drift layered to the cemented filling mining method used in the Longshou mining area has provided a successful mining experience for the safe mining of thick and broken ore bodies. The ore in the eastern part of the Jinchuan Company's No. 2 mining area is thick and shallowly buried, and the mining technical conditions are relatively good, but the grade of the orebody is low. However, due to its high mining cost and low efficiency, the small-section hexagonal route cannot meet the mining requirements of lean orebody in the eastern part. In order to reduce cost and improve mining efficiency, a large-section hexagonal underhand drift cut-and-fill stoping method using medium-deep hole ore was proposed. The hexagonal approach was improved from 4 m (waist width)×5 m (height) to 16 m (waist width)×20 m (height). The centrifugal deformation test was used to analyze the deformation and failure of the large-section hexagonal road filling under the influence of self-weight stress. The test results show that with the gradual increase of centrifugal acceleration, the displacement of the overlying filling body gradually increased. At 70g of centrifugal acceleration, the two gangs collapsed and were destroyed. At 92g, the roof was damaged. The stability of the roof was stronger than that of the two gangs. The maximum cumulative vertical displacement of the two gangs was 0.627 cm. When the roof was damaged, the maximum cumulative displacement was 0.904 cm. The top plate could withstand greater ultimate deformation than the two gangs. The failure mode of the filling body was mainly tensile failure and shear failure, and the hexagonal approach eventually formed a semi-elliptical collapsed arch, and tended to be stable.
