Abstract
Primary breakage is defined as the initial breakage of the coal seam by the cutting action of the continuous miner. A single-breakage process is one that does not involve secondary breakage (or regrinding). Primary dust is defined as dust generated during primary, single breakage. Specially designed single-breakage experiments have been conducted to determine the primary dust generation rates of 17 coal samples obtained from four continuous miner sections, three longwall sections, and the Penn State Coal Data Bank. This research was based on the hypothesis that quantification of the respirable dust generated during single-breakage studies would be useful in developing an index to rank coal seams according to their propensity for respirable dust generation, and may lead to an a priori knowledge of dust generation rates during mining. A better understanding of the factors affecting dust generation rates will facilitate the development of more effective technology for controlling respirable dust generation. Results of these single-breakage studies indicate that the respirable dust generation rate is negatively correlated with moisture and volatile matter contents, but positively correlated with fixed carbon content, fuel ratio (fixed carbon/volatile matter), moist fuel ratio (fuel ratio/moisture), and vitrinite reflectance. However, the respirable dust generation rate was found to correlate poorly with the ash content and Hardgrove Grindability Index (HGI) of the coal samples studied.