# A Review of the Impact of Spontaneous Combustion on Slope Stability in Coal Mine Waste Dumps
###### Abstract  
Mining waste from both underground and open-pit mines is typically placed in surface sites known as mine waste dumps. Over time, as large volumes of mining waste accumulate, these dumps become higher due to the limited surface area allocated to dumping. Ensuring the stability of mine waste dumps is a major concern for both mining operations and local governments due to safety risks to the dumps themselves and their surrounding environments. In some cases of mine waste dump, spontaneous combustion poses a significant challenge, affecting not only the environment but also the slope stability of mine waste dumps. This review synthesizes existing research on the mechanisms of spontaneous combustion, its thermal effects, and the implications for geomechanical stability in mine waste dumps. It also examines methods for monitoring and controlling these processes, identifies gaps in the current research, and suggests directions for future studies. The review also reveals that combustion-induced temperature changes, material degradation, and gas generation significantly impact the geotechnical properties of building material dumps, contributing to slope failure. This review is expected to provide valuable insights that help mining authorities assess risks, minimize impacts, and implement preventive measures to mitigate unexpected spontaneous combustion-induced slope failures in mine waste dumps. s 2025 18 April 20256 June 202  
The situation is the same in other countries; e.g., according to the Ukraine Mining Ministry, in the area of coal mines closed within the boundaries of three Ukrainian coal basins, 341 spoil piles were inventoried, 105 of which had seats of fire [4]. In the coal basins of China, over 6 billion Mg of waste has been deposited between 1500 and 1700 facilities, with an area of over 15,000 ha [5; 6; 7; 8]. Generally, mining waste accumulated on the ground occupies large areas of land, causing many environmental and safety hazards, including vegetation damage, water and soil loss, air and groundwater pollution, spontaneous combustion and landslides of waste dumps. The phenomenon of self-heating and spontaneous combustion is a result of a number of complex physical and chemical processes. Spontaneous combustion within mine waste dumps presents a multifaceted challenge, impacting environmental safety and structural stability. Spontaneous combustion, often triggered by the oxidation of coal under favorable conditions, can lead to significant thermal and mechanical changes within the dump material. These include temperature increases, material degradation, and gas generation, all of which can also cause geological disasters such as surface landslides and explosions. Self-heating and spontaneous combustion is being observed in many coal fields and mine waste dumps worldwide, such as in the Czech Republic [9; 10; 11; 12], Australia [13], China [14; 15; 16; 17], South Africa [18; 19], US [19], Poland [20; 21; 22; 23; 24] and India [25]. It is well-known that the temperature of the environment and that within the slope affect its stability, especially when there are intense thermal fluctuations that cause changes in the volume of soils and rocks, which can lead to thermal stresses and the weakening of the slope. Additionally, an increase in temperature may cause changes in soil moisture and increase permeability, thereby reducing the shear strength of rocks and soils and their cohesion, which can contribute to landslides [26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37]. Other studies have shown how wildfires affect natural slopes and lead to landslides [38; 39; 40]. Figure 1: Location of coal mine waste dumps in Poland [1]. In the case of coal mine waste dumps, the impact of temperature on the slope stability is certainly also significant. On 16 September 2023, a landslide occurred in a coal mine waste dump in southern Poland, where the phenomenon of the self-heating and spontaneous combustion of coal is constantly observed. Figure 2 shows the landslide surface.