Influence of a High-Temperature Environment in Deep Mining on the Characteristics of Coal Spontaneous Combustion

Abstract

ABSTRACT As coal mining continues to progress to deeper levels, the temperature of the coal and rock continues to rise, causing coal spontaneous combustion disasters to become increasingly prominent. This paper studies the spontaneous combustion characteristics of coal in a high temperature environment before and after coal seam mining. The results were as follows: 1) Before mining, under the action of a constant ground temperature, the deep coal seam continuously and slowly released heat, and the higher the ground temperature was, the more heat was released. 2) During mining, after air entered, the coal samples initially maintained the continuous slow heat release. With the continuous entry of air, the coal samples were in an endothermic state. Higher ground temperature provides favorable conditions for coal sample heat absorption and coal spontaneous combustion. 3) When the local temperature rises, the associated hydroxyl groups in the coal sample are gradually activated and become free hydroxyl groups that are more prone to chemical reactions; the methyl groups are destroyed to generate more methylene groups; the aromatic hydrocarbons change significantly after oxygen supply. The long-term high ground temperature environment could lead to an increase in the chemical activity of coal.