Recovering Fine-Size Coal from Alabama Underground Mine Washer Wastes Using the Humphreys Spiral

摘要

The Mineral Resources Institute and State Mine Experiment Station of The University of Alabama conducted Humphreys spiral tests of fine coal waste from nine preparation plants of Alabama underground mining operations, to determine the feasibility of recovering low ash and sulfur fuel meeting steam coal specifications. The ash in the samples ranged from 19.0 to 41.9 percent, and the total sulfur ranged from 0.68 to 1.33 percent. Continuous laboratory tests using a Humphreys spiral gave good recovery of the coal with excellent rejection of the ash and pyritic sulfur. Coal recoveries of 95.6 to 97.5 percent were achieved from the different samples. Ash content of the clean coal products fell within a range of 8.1 to 8.7 percent, with a total sulfur content of 0.81 to 1.29 percent. In quality, the products were comparable or superior to those now being shipped from the preparation plants. (ERA citation 04:038119)