Study On Origin Of Geothermal And Cooling Technique In Deep Mining

Based on the studies on the origin of geothermal and cooling methods in high temperature deposit in Donghuashan Copper Mine, the conclusion of high temperature is caused by heat radiation of original ore and rock, underground water, oxidation of ore, air compression, exploitation of ore and rock and equipments is presented. Mathematical model of heat exchange was established to calculate the total heat and the selection of main routes for heat exchange. Through field measurement, analysis on the compliance of change of temperature was carried out. According to the underground condition in Donghuashan Copper Mine, analysis on cooling measure and the feasibility of stope cool by air pre-cooling of gob area were carried out. By the measurements of enlarge ventilating wind, partly pre-cooling of the inlet air, optimization of multi-stage ventilation system and reasonable distribution of the wind, the aim of cooling is reached. Main results in this paper shown as following:(1) Heat Hazard in Mine is caused by many heat sources. According to the extent of heat, heat sources include the heat radiation of original ore and rock, underground water, equipments, oxidation of ore, air compression and exploitation. Control measures must be carried out according to the extent of heat sources.(2) The distribution of the temperature on the vertical direction I is impacted by the ground water and lithology. In the shallow (above200m) of the mine, geothermal gradient is low due to the cycle of the underground water, which causes air temperature in tunnels is low. This provides favorable conditions for heat exchange between pre-cooled air of surface and high-temperature air in deep. The measurement of pre-cooling in the wasted tunnels in Dongguashan Mine show good effect, which suggests good compliance between theoretical and practice.(3) Theoretical equations of heat exchange of high temperature were established. By the calculation on shaft, underground chambers, transportation roadways and headwork surfaces, analysis of thermodynamic equation of tunnels was carried out through experiments in field. (4) Establish computer solution network of multi-stage station in Dongguashan Copper Mine by the model of ventilation-cooling network of high temperature and the scientifically analysis and process of information obtained. The influence of the temperature of airflow in mine is included in ventilation network for the optimum distribution of wind in main tunnels and middle section to meet the requirements of ventilation and cooling.(5) By taking comprehensive measures, systemic ventilation volume was enlarge to600m3/s, air of gob area was pre-cooling, and ventilation technique of multi-stage station was employed and improved in Dongguashan Copper Mine with high temperature, complex exploit condition, thousand meters mining depth and large mining scale of3million t/a. The level I station of ventilation system controls the air volume and overcome the ventilate resistance, while level II and III stations control the total air volume and overcome the ventilating resistance by the ways of series-parallel. The installed capacity of ventilation system reduces that the temperature is reduced5-8℃in main operating areas. These measures solves the problems of ventilation-cooling and energy-saving in high temperature deep mine, unreasonable distribution of fan pressure between stations of each level during the application of ventilation technique of multi-stage station, and mass air polluted and leak out in the sections of intake and acquired.