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The generation of excessive dust at best is a nuisance and at worst can be deadly. Working in dust causes respiratory prob- lems. Coal dust accumulation provides the necessary link for an ignition to prop- agate into a full blown explosion. Fugitive emissions also send a signal that the cur- rent dust control plan is not working properly. Miners that ignore the warning are taking a gamble. Haul trucks, which are already vision restricted, should not be navigating through dust clouds. While common sense prevails in these situations, there are also external considerations. These could be homes near the mine or communities that have to deal with coal being transported from the mine to the power plant or steel mill. Spillage and dust accumulations are a nuisance that they will not accept. On average, U.S. power plants burn 2.5 million tons of coal per day. Some of that coal is delivered by trucks and barges, but most of that coal is shipped by rail. Unit trains pulling 100 to 150 100-ton railcars traverse the heartland and snake through the Appalachian Mountains. The dust generated by rail transportation and point loading sources is becoming a growing concern. Citing an Australian study, U.S.-based educator and ventilation expert Jürgen Brune, a research professor at the Colorado School of Mines, noted in a 2012 white paper on the topic that 52% of total dust comes from those particulates whirled from vehicles. The second largest contributor is wind erosion at 19%. He presented several formulas that make up the basis for a collection of effective dust control engineering solutions, but boil down to two major questions for opera- tions: where most of the dust has devel- oped and what processes create and generate the largest emissions, and where the greatest areas of sensitivity may exist. Several technical measures can be tak- en to reduce emissions and loss, particu- larly coverings and the use of binding or wetting agents. Some other alternatives include tearing or plowing of a surface to reduce wind erosion, suction systems, surface mine blasting during wet weather, and reduc- ing fall height distances for bulk material dumping. In a recently updated handbook for dust control in coal mining developed by the National Institute for Occupational Safety and Health (NIOSH) researchers, the experts highlighted the key factors for dust control (and overall miner health) from a key transfer location — the mine's primary dump. According to the handbook, dust in the mined product is released from the large volume of material being dumped in a short period of time [at this location], which quickly displaces the air in the hopper and transports the airborne dust released from dumping. If the equipment operators dumping the mined product into the hopper have an effective enclosed cab filtration sys- tem, their exposure to this dust would be reduced. However, if other mine person- nel such as crusher operators and/or maintenance workers work near this pri- mary dump, they can be exposed to this airborne dust. NIOSH recommends enclosing the mine's primary hopper dump with cus- tom-designed walls that will accommo- date the vehicles in use. These walls can be stationary or removable via a flexible material; staging curtains or stilling cur- tains are one option that can be used in the enclosure to provide a physical barri- er that keeps down the natural tendency of dust billowing. Noting it may be a more expensive method, NIOSH researchers also examined the potential for panels of flexible plastic stripping on the dump side of the enclosure and a local exhaust ventilation system to filter dusty air from the enclosed hopper. d u st c o n t r o l B Y D O N N A S C H M I D T 44 www.coalage.com February 2014 Considerations for Controlling Dust Dozer being used to compact stockpile for long-term storage. (Image courtesy of the National Institute for Occupational Safety and Health) In addition to being a safety concern, fugitive dust emission can hurt an operator's image CA_pg44-49_V3_CA_pg46-47 2/12/14 2:13 PM Page 44