Filling mining method to control ground pressure examples (2)

Second, the Jinchuan Nickel mine with two mining areas
After the Jinchuan Nickel Mine No. 2 Mine was put into operation in 1982, the design used a down-layer layered cement filling method. In order to obtain the experience of mining technology, technical and economic indicators and the basis of rock mechanics, the downward cementation filling method was tested between the 14-16 exploration lines in the west.
Three layers have been taken (layered height 4m). The extensometer and multi-point displacement meter are used to monitor the deformation of the deep rock mass of the surrounding rock. Long-term measurements by the extensometer show that the surrounding rock is tensile strain, strain value -7683με, average maximum displacement velocity is 0.161mm/d (Fig. 2), the surrounding rock is compressive strain, strain value is 633με, maximum displacement The speed is 0.12 mm/d (Fig. 3).
Fig. 2 Curve of displacement of surrounding rock on the upper plate
(1 to 7 in the figure is the measuring point number)
Fig.3 Curve of displacement of surrounding rock in the lower plate
(1 to 7 in the figure is the measuring point number)
An observation section is arranged in the surrounding rock of the upper and lower plates to monitor the convergence deformation of the rock mass. The 414-day observation results of the six observation sections on the upper plate have a maximum cumulative convergence value of 259.8 mm and a convergence rate of 0.32 mm/d to 1.05 mm/d (Fig. 4).
Fig.4 Convergence curve of section 1~2 of the surrounding rock
The 350-day observation of the six observation sections of the surrounding rock shows that the maximum cumulative convergence value is 460 mm and the convergence rate is 1.4 mm/d (Fig. 5).
Fig.5 Convergence curve of section 1~9 of the surrounding rock
15 level observation points were buried in the 15~17 exploration line at 1300m level to monitor the subsidence of the roof. After 200 days of observation (three layers were taken), the average sinking speed of the top plate was 0.5 mm/d.
In addition, 14 stress meters are buried in the 15~17 exploration line at 1300m level. The measurement results show that the stress in the surrounding rock of the upper and lower plates, with the development of the mining process, is a complex dynamic change of loading and unloading, that is, the stress increases, decreases, and rises again. High, and then the process of repeated changes.
The comprehensive monitoring of the above various means shows that the cemented backfill of the downward stratified cement filling mining method well limits the deformation of the surrounding rock and the roof, and the displacement is small, which can ensure the safety of the mining work and the mining field is good. Steady state.

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