Semester

Fall

Date of Graduation

2009

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mining Engineering

Committee Chair

Felicia F. Peng.

Abstract

Eight buckets of wet coal samples were collected from Shade Coal Preparation Plant, including the feed, clean coal, refuse, and middlings for fine spiral and coarse spiral, respectively. Float-sink analysis was performed on these size intervals using LMT (Lithium Metatungstate) liquids. Size distribution analysis is conducted for each size fraction of the above eight samples to evaluation the effectiveness of spiral separation. Wet sieving method was used for size distribution analysis.;From the tests, the following conclusion can be drawn: (1) The fine spiral is able to recovery 65.5% of the deslime hydrocyclone underflow as clean coal with an ash content of 8.26%. (2) The ash contents for the refuse and middlings from the fine spiral are almost the same, which could be caused by the improper position of splitter. (3) The coarse spiral recovers 61.5% of the 15-inch hydrocyclone underflow as clean coal with an ash content of 7.26%. (4) For the coarse spiral, the misplacement of mineral contents to the clean coal is not significant as opposed to fine spiral. There are various degrees of misplacement of clean coal to the refuse of the coarse spiral.;Based on the conclusions above, the following recommendations are made: (1) For the fine spiral, the middlings should be mixed with the refuse, instead of mixing with clean coal as final product. The position of splitter between the middlings and the refuse should be adjusted towards the outer rim of the spiral to reduce the ash content in the middlings. (2) For the coarse spiral, the middlings should be combined with clean coal to obtain combined clean coal with satisfactory ash content. If low ash content is desired, the position of splitter between middlings and the refuse can be adjusted towards the outer rim.

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