## 3 Results and Discussion
### Analysis of Warning Level Classification
The t-SNE clustering results, presented in Figure 9, demonstrate distinct distribution ranges for each cluster. High-risk and low-risk clusters exhibit skewed distributions toward temperature extremes, while medium-risk clusters approximate normal distributions centered around intermediate temperatures. Figure 9 shows Cluster 3 appearing last, indicating the highest risk, followed by decreasing risk levels in Clusters 5, 1, and 2. Figure 9 also reveals Cluster 4 disappearing last, representing the lowest risk, with Clusters 6 and 2 showing progressively higher risk levels. The t-SNE clustering results reveal intricate distribution patterns that effectively characterize the progression of coal spontaneous combustion risk levels. The temperature distributions within each cluster demonstrate clear differentiation with minimal overlap, enabling precise risk level classification. Higher risk clusters (3 and 5) exhibit more concentrated distributions, particularly in the elevated temperature ranges, indicating well-defined conditions for severe risk scenarios. In contrast, the moderate-risk clusters (1 and 2) show broader distributions, reflecting the gradual transition nature of the spontaneous combustion process. Most notably, the temporal evolution of the cluster appearances and  
Figure 4.0 Classification of coal spontaneous combustion warning levels with SNE. disappearances closely aligns with the physical progression of coal spontaneous combustion, where lower-risk clusters dominate the early stages and higher-risk clusters emerge as temperatures increase. This natural progression validates the clustering methodology and provides a reliable foundation for the warning level classification system. The clear separation between the clusters, combined with their logical temporal sequence, demonstrates the effectiveness of t-SNE-based clustering in capturing both the spatial and temporal characteristics of spontaneous combustion risk development. Based on the comprehensive analysis of temperature distributions and temporal patterns, six distinct warning levels were established for coal spontaneous combustion risk assessment. These levels progress from \"Safe\" (representing minimal risk conditions), through \"Low Risk\", \"Moderate Risk\", and \"High Risk\", to \"Severe Risk\", and ultimately \"Critical Risk\" (indicating the most dangerous conditions). Each of these warning levels corresponds to specific cluster assignments as detailed in Table 1, providing a systematic framework for risk evaluation and monitoring. These comprehensive analyses of gas indicators, their correlations, and temporal evolution patterns provide a solid foundation for developing more effective monitoring strategies. The insights gained from this study can be directly applied to optimize early warning systems and improve safety measures in coal storage and mining operations. This classification system effectively captures the progressive nature of spontaneous combustion risk while maintaining practical utility for implementation in real-world monitoring scenarios. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Sequence** & **t-SNE Cluster** & **Warning Level** \\ \hline
1 & 4 & Safe \\
2 & 6 & Low Risk \\
3 & 2 & Moderate Risk \\
4 & 1 & High Risk \\
5 & 5 & Severe Risk \\
6 & 3 & Critical Risk \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The warning levels corresponding to the clustering results. Figure 9: Classification of coal spontaneous combustion warning levels with t-SNE.