# A Review of the Impact of Spontaneous Combustion on Slope Stability in Coal Mine Waste Dumps
## 6 Conclusions  
Due to the fact that mining plays a crucial role in the economy and national security of many regions worldwide, the quantity and size of mine waste dumps are expected to increase over time. As these dumps grow in volume and dimensions, the likelihood of self-heating and spontaneous combustion events also rises--particularly in mining areas. Spontaneous combustion alters the thermal conditions within the waste material, which directly influences the geomechanical behavior of the dump materials. These thermally induced geomechanical changes can, in turn, impact the overall stability of the waste dump slopes. In other words, spontaneous combustion within mine waste dumps introduces complex challenges related to slope stability, posing significant risks to both environmental safety and operational sustainability. Due to the variability of geotechnical properties, the spread of combustion within the mine waste dump and the ongoing process of waste deposition should be subject to continuous detailed monitoring. Such a monitoring should cover changes in dump slope geometry; the degree of compaction of individual layers forming the dump body; slope displacements resulting from geometric changes during its dumping operations; the type and grain size of freshly deposited mine waste; ongoing slope stability analyses and calculations for each phase of slope construction; and thermal imaging surveys and in-depth thermal state investigations during the dumping process. The primary objective of this monitoring is the early warning and prevention of potential spontaneous combustion and its possible consequences. This approach is also essential for the selection and assessment of fire prevention methods, both during the construction phase of the reclamation body and the post-construction phase, ensuring the long-term safety and performance of the dump structure. A number of practical measures are recommended to maintain the stability of mine waste dump slopes. These include conducting stability analyses for individual mine waste slopes and continuous monitoring such as geodetic and photogrammetric measurements to track slope displacements over time. Additionally, geophysical investigations should be carried out to detect potential voids within the dump body. The most commonly used geophysical methods include ground-penetrating radar, engineering seismics, electrical resistivity tomography, gravimetric methods, and electromagnetic methods. These investigations are a crucial complement to geotechnical studies, especially in terms of accurately identifying the structure and geomechanical condition of the dump materials. It is also  
Figure 6: A simplified concept of the city/local heating system configuration in a mine waste dump. recommended that the compaction of freshly deposited mining waste is monitored and, if necessary, that the surface layers of the dump body are re-compacted or sealed to achieve the required compaction indicators for each material (soil) layer. Preventive measures to mitigate spontaneous combustion at mine waste dumps have traditionally been costly, time-consuming and labor-intensive. Until now, despite these efforts, they have not proven fully effective in eliminating or sustainably controlling the issue. Therefore, eco-friendly mitigation techniques should be developed for the long-term management of mine waste dumps affected by spontaneous combustion. An alternative approach worth considering is controlling and utilizing spontaneous combustion as a geothermal heat source. This concept could transform a hazardous phenomenon into a beneficial resource. Future work should focus on the design, feasibility, and development of such a system, as well as its implementation. Investigating this approach may offer a sustainable and innovative solution for managing mine waste dumps prone to spontaneous combustion.