A review on the mechanism, risk evaluation, and prevention of coal spontaneous combustion in China

Abstract

In recent years, the ecology, security, and sustainable development of modern mines have become the theme of coal mine development worldwide. However, spontaneous combustion of coal under conditions of oxygen supply and automatic exothermic heating during coal mining lead to coalfield fires. Coal spontaneous combustion (CSC) causes huge economic losses and casualties, with the toxic and harmful gases produced during coal combustion not only polluting the working environment, but also causing great damage to the ecological environment. China is the world's largest coal producer and consumer; however, coal production in Chinese mines is seriously threatened by the CSC risk. Because deep underground mining methods are commonly adopted in Chinese coal mines, coupling disasters are frequent in these mines with the coalfield fires becoming increasingly serious. Therefore, in this study, we analyzed the development mechanism of CSC. The CSC risk assessment was performed from the aspects of prediction, detection, and determination of the "dangerous area" in a coal mine (i.e., the area most susceptible to fire hazards). A new geophysical method for CSC determination is proposed and analyzed. Furthermore, the main methods for CSC fire prevention and control and their advantages and disadvantages are analyzed. To eventually construct CSC prevention and control integration system, future developmental direction of CSC was given from five aspects. Our results can present a reference for the development of CSC fire prevention and control technology and promote the protection of ecological environment in China.

The stage analysis and countermeasures of coal spontaneous combustion based on “five stages” division

“…Among them, the coal-oxygen-compound theory has been widely accepted by scholars because the adsorption of oxygen to coal and the production of an exotherm, which is core of this theory, has been proven by experiments. Some scholars [ 2 – 6 ] have supported this theory and described and discussed the mechanisms of the spontaneous combustion of coal as follows: (1) the percolation of air through coal results in a measurable rise in temperature, which is caused by a series of adsorptive, absorptive, and chemical processes; (2) the heat generated gives rise to an increase in the temperature of the coal, which accelerates the rate of coal oxidation; (3) these actions cause the coal to self-heat, and if conditions are favorable, spontaneous combustion will occur.…”

Research on a Gas Index Reflecting the Sorption Process on Carbon Materials in Coal Mines

“…Negative results of this natural process are reflected in the necessary isolation of the threatened area, massive destruction of the valuable resource of coal, and a risk for the work safety of miners. Various methods have been developed and introduced to mining practice in order to accurately detect fires and their positions in underground mines [2,3]. In coal-producing countries in the world, the most used method is based on the analysis of the mine air composition, which consists of determining the gaseous components, both under safe conditions and when there is any change in composition of mine air [4].…”

Experimental study on controlled-release inhibitor foam for restraining spontaneous combustion of coal

“…In major coal producing countries, such as China, the United States, Australia and India, coal fire disasters are very common and are considered as a global disaster problem (Havva, 2007;James et al, 2009;Kong et al, 2017;Mohalik et al, 2017;Parsa et al, 2017;Wang et al, 2018;Yang and Qiu, 2019). More than 95% of Chinese collieries perform underground coal mining, in which fire accidents due to spontaneous coal combustion account for more than 90% of the total number of mine fires (Deng et al, 2008;Fan et al, 2020Fan et al, , 2019.…”