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Making the case for belt air.
Coal USA Mag 2009 Aug; :26/28
The use of belt air to ventilate the working section during gateroad development can increase the total airflow at the last open crosscut but with possible disadvantages. In December 2007, the Technical Study Panel on the Utilization of Belt Air released a report concerning the use of belt air in US coal mines. As of February 2008, there were approximately 48 operating coal longwall panels in the U.S. Of these, five were four-entry panels, 39 were three-entry), panels and four were two-entry (Utah) panels. The four-entry gateroad longwalls are characteristically located in the gassiest coal seams in the US. All two-entry gateroads are located in Utah where ground control is sues preclude the use of developments with more than two entries. The most common three-entry sys tem generally consists o f a belt entry (ventilating the working section or not), a middle intake and a dedicated return. Belt air can either be directed to the working section or not. For shorter gateroads, development methane liberation in the face area is the primary factor influencing airflow requirements. However, for long gateroads, rib emissions can far exceed the methane liberated at the development face. In this case, the total amount of air available at the section mouth for dilution of the rib emissions limits gateroad development distance. All of these methane emission sources can be affected by pre-mining or in situ methane drainage. For this research, Mine Ventilation Services' VnetPC 2007 ventilation simulation software was used to analyze gateroads of various lengths using 300m long segments. Turbulent airflow was used to determine leakage for the stoppings. Stopping resistances were set at 2000 and 10,000 Ns2/ m8 (179 and 895 x10-(10) in'min2 / ft6) to represent poor to excellent stopping construction.
Mining-industry; Underground-mining; Models; Coal-mining; Longwall-mining; Ventilation
Journal Article; Lay Publication
Coal USA Magazine
PA; CO; WV
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division