IMPROVING DENSIFICATION OF COAL TAILING USING DEEP CONE THICKENER

摘要

Increased mechanization in the underground coal mining industry has decreased selectivity and increased the volume of refuse. Coal preparation separates noncombustibles material from coal. Thus, a coal preparation plant separates the material it receives into a product stream and a reject stream, which may be further divided into coarse and fine refuse streams. rnDepending on the source, 20 to 50 percent of the run-of-mine material ends up in reject streams. One of the reject streams is a slurry stream. This is a blend of water, coal fines, silt, sand, and clay particles, which is commonly disposed of in an impoundment. The coal industry is required to monitor the impoundment constantly and maintain the dikes holding the slurry. There have been several incidents of impoundment breakthrough. Of these, Buffalo Creek in West Virginia in1972 and recently, Martin County Coal in Kentucky, have drawn the attention of federal and state governments and local people due to heavy losses of life and property. rnIn this paper an advanced thickening technique known as Paste Thickening echnologymarketed by Dorr-Oliver EIMCO, which has been successfully applied in the alumina processing industry, will be evaluated in the dewatering of fine coal tailings. The technique utilizes the DEEP CONE Thickener", which is specially designed to concentrate tailings into a high percent solid, so it can discharge as a paste. The thickened material could be stacked at a low angle of repose rather than stored in a pond. rnThus, the fine refuse slurry ponds could be completely eliminated. The paper will describe study of the basic rheological properties of the flocculated fine refuse solids for producing a highly thickened solid capable of disposing of as a paste. It is also the objective of the research to utilize the rheological data obtained in pilot-scale testing of the DEEP CONE Thickener" to obtain technical and economic data for a commercial operation.