# Analysis on the Spatial-Temporal Distribution Patterns of Major Mine Debris Flows in China
## 5 Regional Comprehensive Evaluation of Mine Debris Flow Distribution
### Comprehensive Evaluation Model  
The evaluation factors are graded and assigned a score \(\rm F_{i}\) according to the proportion of significant mine debris flow occurring in different spatial and temporal conditions to the total statistics combined with the qualitative analysis of the impact degree to achieve quantification (Table 5). The evaluation of mine debris flow distribution area is calculated \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Item** & **Eigenvector (\(\omega\))** & \
\begin{tabular}{c} **Weighting** \\ **Value (\(W_{i}\))** \\ \end{tabular} &
\begin{tabular}{c} **Maximum** \\ **Eigenroot (\(\lambda_{max}\))** \\ \end{tabular} & **CI** \\ \hline Geological environment & 0.672 & 13.435\% & & & \\ Tectonic conditions & 0.339 & 6.778\% & & & \\ Multi-year average & & & & \\ daily maximum precipitation & 2.514 & 50.282\% & 5.243 & 0.061 \\ Vegetation cover & 0.174 & 3.482\% & & & \\ Anthropogenic factors & 1.301 & 26.023\% & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: AHP Hierarchical analysis results. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Geological** & \begin{tabular}{c} **Tectonic** \\ **Environment** \\ \end{tabular} & \begin{tabular}{c} **Multi-Year** \\ **Conditions** \\ \end{tabular} & \
\begin{tabular}{c} **Vegetation** \\ **Maximum** \\ **Precipitation** \\ \end{tabular} &
\begin{tabular}{c} **Anthropogenic** \\ **Factors** \\ \end{tabular} \\ \hline
**Geological** & 1.000 & 3.000 & 0.200 & 5.000 & 0.333 \\
**environment** & 0.333 & 1.000 & 0.143 & 3.000 & 0.200 \\
**Tectonic conditions** & 0.000 & 7.000 & 1.000 & 9.000 & 3.000 \\
**Multi-year average** & & & & & \\ daily maximum precipitation & 5.000 & 7.000 & 1.000 & 9.000 & 3.000 \\
**Vegetation cover** & 0.200 & 0.333 & 0.111 & 1.000 & 0.143 \\
**Anthropogenic** & 3.000 & 5.000 & 0.333 & 7.000 & 1.000 \\
**factors** & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: AHP Judgment Matrix. by multi-factor composite index method, and the composite index F is the comprehensive quantitative value of mine debris flow distribution area evaluation, and the threshold value is set according to the size of F to grade the mine debris flow distribution area. The comprehensive index of mine debris flow distribution area evaluation is obtained by the weighted superposition calculation of each evaluation factor, and its calculation model is:  
\[F=\sum_{i=1}^{n}W_{i}F_{i}\]  
_F_--comprehensive index of regional evaluation. _Wi_--the weight value of each evaluation factor, obtained from Table 4.  
_Fi_--the quantitative value of the score of each evaluation factor, obtained from Table 5.  
The model calculates the evaluation score of major mine debris flow area (Figure 5) and divides the grade according to the selected threshold value of the score: \(F\geq 8\): the geological environment of mines in this area is difficult to the formation of debris flow, gentle terrain, no geological hazards, few loose piles, no hydrodynamic conditions, high vegetation coverage, low intensity of mining activities, prevention and control projects. 8 > \(F\geq 6\): The geological environment of mines in this area is unfavorable to the formation of debris flow, less undulating terrain, less destructive geological hazards, fewer loose piles, not rich in hydrodynamic conditions, high vegetation coverage, and less hazards caused by mining development activities. 6 > \(F\geq 3\): the mining geological environment in this area is more favorable to the formation of debris flow, more undulating terrain, more geological hazards, more loose piles, more abundant hydrodynamic conditions, less vegetation cover, and frequent mining development activities. \(F<3\): The geological environment of the mine in this area is very favorable to the formation of debris flow, steep terrain, frequent geological hazards, more loose piles, rich hydrodynamic conditions, low vegetation cover, high intensity of mining development activities, presence of unreasonable piles and drains, and poor engineering stability.