Substantiation of dredging technology of water-bearing deposits at subzero air temperatures

Abstract

The article deals with the problem of reducing dredge performance when operating at subzero air temperatures. This problem is particularly relevant for deposits located in the Far North, where the dredging season is limited by climatic conditions. During the period of subzero air temperatures dredge performance decreases significantly due to the icing of dredge structure. In consequence, dredging operations are terminated until the occurrence of favorable conditions for work. The article presents the review of the existing methods aimed at extending the dredging season, providing their systematization, which is based on the methods of water lanes’ maintenance and formation in the open-pit dredging. The authors propose a method to isolate the open-pit mine with artificial materials, as well as consider the application of similar structures in the dredging industry. Existing structures are used to store mineral dumps, protect the environment from dust, as well as for other purposes. It was revealed that the most perspective material to isolate dredges was polycarbonate, possessing a number of advantages. An experiment was conducted to confirm the effectiveness of this method by creating a facility in the form of a hangar model. The hangar model was performed on a scale in compliance with geometric similarity. Thermal sensors and an infrared camera were used to record the results. This allowed obtaining the distribution of thermal fields in the constructed experimental hangar. The developed mathematical model allows determining the temperature inside the isolated space of the open-pit dredging depending on the water temperature of the open-pit and the ambient air temperature. It is revealed that the application of the proposed method will extend the dredging season, or even make it year-round. The authors have calculated hangar sizes while all sizes were accepted minimum for reducing the cost of construction and keeping the heat inside it. The application of the proposed method for straight and oblique dredging was considered. The hangar area was determined for the development of mines with dredges of different standard size. The optimal method of rock excavation was revealed. The authors offer the scope of application, as well as the technology aimed at extending dredging season.