Моделирование теплового режима рудного штабеля при кучном выщелачивании золота в холодном климате = Modeling of thermal conditions for ore stockpile in heap leaching of gold in cold climates

На основе математического моделирования теплового процесса предлагается методика расчета продолжительности воздействия нагревательным инструментом при сварке газопроводов из полиэтиленовых труб при температурах воздуха, ниже регламентируемых. Исследуется степень кристалличности материалов сварного соединения, полученных при остывании в естественных условиях низких температур. The paper presents the results of research, which primary practical goal is wide implementation of the heap leaching technology in areas with harsh climatic conditions, i.e. presence of permafrost and long winter periods. The main limiting factor for applying the method in regions with cold climate is that the leaching efficiency of any type of gold-bearing ores considerably depends on the temperature conditions of the ore stockpiled and the leaching solution, which in turn determines the seasonal nature (only in the Summer months) of gold mining operations utilizing the heap leaching technology. Appropriate physical properties need to be set for all the materials available in the area to be modeled. The boundary conditions also have to be defined for all heat transfer conditions used in the model. Modeling of the leaching solution filtration in the Frost.Thermo software suite is based on the extensively tested equation for groundwater filtration derived from the Darcy law. Solution of the thermal conductivity equation in the 3D formulation is carried out numerically using the explicit method of finite differences. According to the results of computer modeling in the Frost 3D software suite, emergency failure of the thermal insulation coating on the stockpile surface leads to freezing of the rocks in the stockpile down to a considerable depth. Calculations of the thermal conditions of the ore stockpile have been carried out for different conditions of its surface thermal insulation. The most optimal method to thermally insulate the walls of the stockpile is to cover the slopes (walls) of its lower tier with a 1-meter thick snow layer, while the slopes (walls) of the upper tiers should be insulated with a film having an air interlayer of 3 cm.