Implementation of fine screening technology in fine coal tailing circuits

Abstract

The coal industry has been moving toward elimination or size reduction of tailings ponds, as they pose major environmental and potential safety concerns. Thickening and dewatering of the dilute slurry to produce a high solids discharge has become the industry standard practice for processing coal tailings. Large filter presses are normally used for dewatering the thickener underflow. However, filter presses are well known for their high cost, non-continuous operation, high maintenance, and large floor space requirements. Alternatively, high frequency fine dewatering screens have been applied to dewater thickener underflow, working in conjunction with filter presses. This process not only produces a high solids discharge, eliminating the need for a large number of tailings ponds, but it also reduces drastically the high cost of large filter presses, ultimately reducing the overall dewatering costs. This paper describes two applications in which coal processors in China and India have benefitted from fine screening technology.