Water-source heat pump in governance of heat hazard in deep mines – An example of Jinfeng Gold Mine, Guizhou

The deep mining of mineral resources is the future direction of the mining industry, and thermal hazards in mines have become a major factor limiting safe production. Due to the working face of deep mines being located in temperature-increasing strata, combined with underground industrial heat sources, these heat sources exhibit characteristics such as being numerous and dispersed, prolonged duration, and high instantaneous heat release power. Current conventional cooling technologies such as ventilation optimization, roadway and equipment layout optimization, and isolation of heat sources cannot meet the cooling needs of deep mines, necessitating the development and application of efficient, green, and high-capacity artificial refrigeration technologies. This paper first discusses the principles of heat pumps and examines the spatial and temporal distribution characteristics of heat sources and heat sinks both on the surface and underground in mining areas. It summarizes the challenges of applying artificial cooling technologies to the management of thermal hazards in deep mines. The Jinfeng Gold Mine in Guizhou is currently mined to a depth of 630 meters. Using this mine as an example, the sources of underground thermal hazards were identified, and the cooling load was calculated. Cooling targets were selected based on the production characteristics of the mine, and the feasibility of using nearby water bodies as heat sinks through water-source heat pump technology for underground cooling was explored. Field investigations, measurements, theoretical calculations, and numerical simulations were conducted to analyze the thermal capacity and stability of four nearby water bodies: the Lüyin Pond, Luofan River, Beipan River, and the mine diversion channel. Initial investment and operating costs were calculated for water-source heat pump schemes based on different water bodies, leading to a technical and economic comparison. After comprehensive analysis, the proposal to use the mine's water diversion channel as the heat source for a water-source heat pump to cool the incoming air at the mine entrance was recommended. This scheme is characterized by good cooling effectiveness, low investment, large stable heat sink capacity, and minimal ecological impact.