Study of the influence of the characteristics of loose residual coal on the spontaneous combustion of coal gob

Abstract

Mine fires are becoming a serious issue as the intensity of mining increases, especially in deep mines. Loose coal gob has a hidden ignition location and a high possibility of spontaneous combustion, which makes fire prevention difficult. Therefore, based on the theory of gas seepage and the characteristics of loose coal, a model of air leakage and spontaneous combustion in gob is established in this paper. Using working face #10414 in the Yangliu coal mine as an example, the relationship between the three spontaneous coal combustion (CSC) zones and the three stress zones is analyzed and verified by combining a FLAC3D simulation with field monitoring. In addition, the influence of advancing speed on the CSC is discussed, and suggestions for fire prevention are presented. The results show that the variation in the calorific value of the CSC with increasing degree of looseness of the residual coal in the gob forms an arch‐shape. There is a one‐to‐one relationship between the distribution of the three stress zones and the three CSC zones. In addition, as the advancing speed increases, the contact time between the loose coal body and the air decreases and the possibility of CSC decreases. This study provides a scientific basis for fire prevention and control in mines.

Analysis of the Fire Propagation in a Sublevel Coal Mine

“…The study of spontaneous combustion, together with the rockmass characteristics, has been investigated as well [31]. The influence of residual coal in the gob and the rockmass characteristics are crucial for potential fires in this area, influencing the mixture of waste with coal and the airflow leakages [32].…”

Targeted inertization with flue gas injection in fully mechanized caving gob for residual coal spontaneous combustion prevention with CFD modeling

“…20,38,39 The development and prevention of spontaneous combustion in gobs also involve multifield coupling problems that include underground fissure fields, flow fields, oxygen concentration fields, and temperature fields. [40][41][42][43][44][45] In this research, the 3D coupling model of coal spontaneous combustion in a fully mechanized caving face was established based on the following basic assumptions: (a) Each component of the mixture gas in the gob was treated as an ideal gas and its flow diffusion was approximated as a stable process. (b) The residual coal and the rock mass in the gob were regarded as continuous and isotropic porous media.…”

“…The spontaneous combustion of coal originates from a series of complex physical and chemical reactions after the coal is exposed to air 20,38,39 . The development and prevention of spontaneous combustion in gobs also involve multifield coupling problems that include underground fissure fields, flow fields, oxygen concentration fields, and temperature fields 40‐45 …”

Study of Adsorption Characteristics of CO2, O2, and N2 in Coal Micropores and Mesopores at Normal Pressure

“…Coal is a very important energy and chemical raw material, but in the actual production process, mine fires seriously restrict the development and utilization of coal resources in our country. In recent years, although the level of colliery fire prevention technology has been greatly improved, the situation of mine fire prevention and control is still severe. − Compared with other fire-fighting technologies (grouting, gel, foam, pressure equalization, etc. ), inert gas injection for fire extinguishment technology has the advantages of simple operation, wide application range, and little impact on mine machinery and equipment, so it is widely used in colliery, − while CO 2 and N 2 are commonly used inert gases.…”