Engineering Controls Database

Best Practices for Dust Control in Coal Mining – Longwall Mining Operations – Intake Roadways

Problem:	Respirable dust exposure has long been known to be a serious health threat to workers in many industries. In coal mining, overexposure to respirable coal mine dust can lead to coal workers’ pneumoconiosis (CWP). CWP is a lung disease that can be disabling and fatal in its most severe form. In addition, miners can be exposed to high levels of respirable silica dust, which can cause silicosis, another disabling and/or fatal lung disease. Exposure to coal mine dust may also increases a miner’s risk of developing chronic bronchitis, chronic obstructive pulmonary disease, and pathologic emphysema. Once contracted, there is no cure for CWP or silicosis. The goal, therefore, is to limit worker exposure to respirable dust to prevent development of these diseases.
What this means to you:	CWP contributed to the deaths of 10,406 U.S. miners during 1995–2004 [NIOSH 2008]. Pneumoconiosis continues to be a very serious health threat to underground coal mine workers. Longwall workers can be exposed to harmful respirable dust from multiple dust generation sources, including the intake entry, belt entry, stageloader/crusher, shearer, and shield advance. Respirable dust concentrations outby the face area in intake roadways may have a significant effect on dust exposures of longwall face workers if not properly addressed. Also, as longwall production has increased, mine operators are bringing larger quantities of air to the face to control methane and dust liberation.
Description of control:	The following practices can help control respirable dust levels along intake roadways: Limit support activities during production shifts. Vehicle movement, removal of stoppings, and delivering/unloading supplies during production shifts can elevate intake dust levels. These activities combined with increased air velocities can cause dust to be entrained into the face ventilating airstream, especially if they occur close to the last open crosscut. Apply water or hydroscopic compounds to control road haulage dust. Water application to the mine floor is crucial to control respirable dust in the intake roadway. Operators must be diligent in monitoring moisture content of the dust along intake roadways, especially with the increased amount of air traveling toward the face and during winter months. This air amplifies the potential for the roadways to dry out more quickly. The moisture content of the haulage floor should be approximately 10% [Organiscak and Reed 2004; Kost et al. 1981]. Hydroscopic compounds such as calcium, magnesium chloride, hydrated lime, and sodium silicates increase roadway surface moisture by extracting moisture from the air. Applications of these materials will help maintain the moisture content of the road surface [Organiscak et al. 2003]. Use surfactants. Surfactants such as soaps and detergents dissolve in water and can be beneficial in maintaining the proper moisture content of the intake roadways. Surfactants decrease the surface tension of water, which allows the available moisture to wet more particles per unit volume [Organiscak et al. 2003].
References:	NIOSH [2010]. Information circular 9517. Best practices for dust control in coal mining. Morgantown, WV: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2010-110. Kost JA, Yingling JC, Mondics BJ [1981]. Guidebook for dust control in underground mining. Bituminous Coal Research Inc. U.S. Bureau of Mines contract J0199046. NTIS No. PB 83-109207. NIOSH [2008]. Work-related lung disease surveillance report, 2007. Morgantown, WV: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2008143a. Organiscak JA, Reed WR [2004]. Characteristics of fugitive dust generated from unpaved mine haulage roads. Int J Surface Min Reclam Environ 18(4):236–252. Organiscak JA, Page SJ, Cecala AB, Kissell FN [2003]. Surface mine dust control. In: Kissell FN, ed. Handbook for dust control in mining. Pittsburgh, PA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2003-147, IC 9465, pp. 73–81.
Keywords:	coal miners coal mining mining underground mines