Research on the spatiotemporal dynamics mechanism of heat hazard formation in high-temperature working faces of deep mines

• Developed a distributed fiber optic temperature sensing approach to reveal the spatiotemporal variation of airflow temperature in high-geothermal fully mechanized caving faces. • Identified surrounding rock as the dominant heat source (45.18 % of total dissipation) and quantified dynamic heat dissipation patterns during production and maintenance periods. • Established a simplified thermal resistance network model to characterize periodic heat accumulation during production and exponential decay during maintenance. Mining activities in high-temperature working faces of deep mines cause dynamic variations in heat source dissipation, challenging the timely and efficient supply of cooling energy. This study utilizes a distributed fiber optic temperature sensing system to continuously monitor airflow temperatures during production and maintenance periods. A simplified dynamic thermal resistance network model analyzes the heat transfer between airflow and heat sources. Results indicate that the surrounding rock is the dominant heat source, contributing 45.18 % of total heat dissipation. During production, heat dissipation from surrounding rock increases exponentially with mining progress, with the return airflow temperature rising up to 7.6 °C. During maintenance, dissipation decreases initially and then stabilizes, with an average return airflow temperature rise of 4.5 °C. The return airflow temperature rise fluctuates periodically and shows a stepwise increase along the airflow path due to dynamic heating rates. Heat dissipation accumulates spatially and increases periodically over time during production, while the coal wall temperature decays continuously during maintenance, reducing heat dissipation. These findings provide a theoretical basis for precise cooling energy management in deep mining operations.