![]() Worst Available Techniques (WAT) is mine abandonment with no attempt to recontour the gravel or to spread topsoil. We demonstrate that BAT was achieved in Australia as early as 100 years ago, and a form of BAT is now seen in Mongolia. Best Available Techniques (BAT) is to ensure the land behind the dredge is immediately re-contoured, topsoiled, planted and given aftercare. Diagnostic of large bucket-line dredges these bare mounds of washed gravel be traced along thousands of kilometers of disrupted floodplains by means of zero-cost remote sensing. Many trunk valleys in NE China, Siberia and the Russian Far East are extensively damaged, and the damage is spreading In their wake, the gold dredges leave arcs of dumped gravel (‘bananas’) stacked against one another as long ribbed mounds (‘crocodiles’). The paper illustrates the impact of large bucket-line gold dredges. The authors offer the scope of application, as well as the technology aimed at extending dredging season. The optimal method of rock excavation was revealed. The hangar area was determined for the development of mines with dredges of different standard size. ![]() The application of the proposed method for straight and oblique dredging was considered. The authors have calculated hangar sizes while all sizes were accepted minimum for reducing the cost of construction and keeping the heat inside it. It is revealed that the application of the proposed method will extend the dredging season, or even make it year-round. 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. This allowed obtaining the distribution of thermal fields in the constructed experimental hangar. Thermal sensors and an infrared camera were used to record the results. The hangar model was performed on a scale in compliance with geometric similarity. An experiment was conducted to confirm the effectiveness of this method by creating a facility in the form of a hangar model. ![]() It was revealed that the most perspective material to isolate dredges was polycarbonate, possessing a number of advantages. Existing structures are used to store mineral dumps, protect the environment from dust, as well as for other purposes. 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. 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. In consequence, dredging operations are terminated until the occurrence of favorable conditions for work. During the period of subzero air temperatures dredge performance decreases significantly due to the icing of dredge structure. This problem is particularly relevant for deposits located in the Far North, where the dredging season is limited by climatic conditions. The article deals with the problem of reducing dredge performance when operating at subzero air temperatures. The study draws attention to small changes in design that allow bucket line dredges of medium to large size to become BAT sufficient to satisfy stringent environmental concerns. The goal of the study was to identify 'Best Available Techniques’ BAT for bucket-line gold dredges. ![]() The study assesses the advantages and disadvantages of large, medium and small bucket-line dredges in terms of mining and impacts. Just as important has been the success of local manufacturers in cutting costs, adopting new ideas such as Caterpillar chains for the bucket, and the ease of making small bucket-line dredges in simple workshops. The persistence of bucket-line gold dredges in Siberia and Asia is not only due to the presence of large gold placers suitable for dredging. The decline of bucket-line gold dredges in North America and Australasia is due to exhaustion of the richest placers suitable for dredging, increased concerns about the environment, and the very high capital cost of large capacity machines. Rather than being out-dated technology the remain at the cutting edge in terms of efficiency, effectiveness, reliability and profitability. The study shows bucket-line gold dredges are still being manufactured and launched in Siberia, Mongolia and China. Yet such dredges are still active in large parts of the world. Bucket-line gold dredges have existed for more than a century and in North America and Australia and are preserved as relics.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |