## 2 Typical Scheme and Disadvantages of Sublevel Caving Method  
### Typical Scheme of Sublevel Caving Method  
The sublevel caving method is a widely used mining method in underground mines, especially in metal mines, and in practical application, the parameters required for its typical scheme design include stage height, segmental height, approach spacing, etc. The selection of these parameters will be optimized according to the geological conditions of the mine, the characteristics of the ore body, and the mining requirements. Table 1 shows the structural parameters of the sublevel caving method applied in some domestic and foreign mines.  
As shown in Figure 1, it is a schematic diagram of a typical scheme of the sublevel caving method in China.  
First, for the quasi-mining stage, its stage transportation level alleys, ore-pass, and ramps are generally arranged in the peripheral rock of the lower pan of the ore body; the rock drilling outlet approach is arranged vertically (or along strike); and the upper and lower neighboring segments of the rock drilling outlet approach are arranged in a diamond shape to maximize the recovery of residual ore in the ridges between the upper segments of the rock drilling outlet approach. Second, in the cutting process, the main purpose is to form a cutting chute at the end of the rock drilling approach, excavate a cutting transverse alley and a cutting pati at the end of the rock drilling approach, and expand the blasting to form a cutting chute with the cutting pati as a free surface. Finally, in the process of mining back, it is necessary to pay attention to the arrangement of the gun holes and the balance of the charge during rock drilling to prevent the occurrence of damage to the brow line of the mine release. When discharging the ore, it must be strictly managed to minimize the loss rate and the dilution rate to improve the economic efficiency of the mine. As the rock-cutting ore outlet approaches are all single-ended roadways, it is impossible to form a penetrating airflow, resulting in poor ventilation of this mining method, so it is necessary to  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Mine Name** & **Stage Height** & **Chute Spacing** & **Waste Rock Chute** & **Segment Height** & **Approach** & **Inlet** \\
**Spacing** & **(m)** & **(m)** & **Spacing (m)** & **(m)** & **Spacing** & **Specifications** \\ \hline Damiao Iron Mine & 61–70 & 50 & - & 10 & 10 & 4.0 \(\times\) 3.0 \\ \hline Chengchao Iron Mine & 70 & 40–60 & 50 & 10 & 10 & 3.2 \(\times\) 3.2 \\ \hline Dachang Tin Mine & 90 & 60 & 80–120 & 12–13.5 & 10 & 4.0 \(\times\) 3.0 \\ \hline Meishan Iron Mine & 60 & 60 & - & 10–13 & 10 & 4.0 \(\times\) 3.0 \\ \hline Fushan Iron Mine & 50 & 50 & & 10 & 8 & 3.0 \(\times\) 3.0 \\ \hline Huashugou Iron Mine & 60 & 40 & - & 10,12 & 10 & 3.5 \(\times\) 3.5 \\ \hline Fengshan Copper Mine & 50 & 50 & 100 & 10 & 10 & 3.0 \(\times\) 2.8 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Structural parameters of some domestic mines applying the sublevel caving method.  
Figure 1: Diagram of mining method of sublevel caving method.  
use local ventilation fans to assist ventilation. For the sublevel caving method, the mining sequence will affect the loss and dilution of ore. Usually, the upper section is mined first, and the same section can be mined in various sequences, but each approach should be mined in a backward manner.