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This paper presents physical, mineralogical and wetting characteristics for dust samples from the Interior Basin coal mines. The samples were from three sources: 1) Produced in the laboratory from bulk samples of coal and immediate roof and fl oor strata, 2) In-mine samples collected through gravimetric sampling of active mining areas, and 3) In-mine samples collected from wet-scrubbers on continuous miners. Particle size distribution analysis showed that about 30, 67, 68 and 60% of dust particles are in the respirable range (b10 μm) for bulk samples of coal, and roof, andfl oor strata and for in-mine dust samples collected fromscrubber, respectively. SEM image analysis of in-mine gravimetric dust samples showed most particles to be spherical and large number of particles to be of≤1 μm. Bulk samples of roof andfl oor strata were determined to have varying quartz content from 6.2 to 13.7% by weight. Quartz, kaolinite, calcite, pyrite and illite were the most prevalentminerals in bulk dust samples. XRD data showed presence of quartz in un-wetted dust particles indicating the co-existence of minerals and macerals. Coal petrography analysisshowed vitrinite as the dominant maceral (68–86%) in bulk coal samples.Two approaches were used to assess dust wettability rates: 1) fi xed-time wettability that attempts to simulate wetting around mining environments, and 2) absolute-time wettability that evaluates intrinsic wettability rates. Fixed-time wettability for coal dusts were in the range 57–99% (%wt.)with majority of mines having valuesabove 90%. The middle portion of the coal seam was found to be least wettable. The contact time between dust particles and water droplets was an important factor for improving wetting of coal dust. An increase in contact time from 10 to 25 s showed 3–27% improvement in fi xed time wettability. Absolute-time wettability datashowed that coarser particles required more time for complete wetting. The data above is being actively used to design engineering controls for improved dust control in mines.Coal and quartz dust control is a major issue in underground coalmines. Prolonged exposure to excessive respirable size coal and silicadusts can lead to coal workers pneumoconiosis (CWP) and silicosis.Over the last six decades, U.S. Bureau of Mines (USBM), National Instituteof Occupational Safety and Health (NIOSH), Dust Control GenericCenter, Mine Safety and Health Administration (MSHA), industry andacademic institutions have performed excellent research in support ofindustry needs. However, NIOSH's Coal Workers' X-Ray SurveillanceProgram (CWXSP) from 1970 to 2009 indicates (Figs. 1 and 2, source:National Institute of Occupational Safety and Health, 2011) an upwardtrend in the prevalence of CWP and Progressive Massive Fibrosis(PMF, which is a complex form of CWP) since 2000 after years of decline.In addition, during the period 2000–2013, over $5.67 billion(Social Security Administration (SSA), 2013) in CWP bene fi ts werepaid to underground coal miners and their families. A recent study byEpidemic Intelligence Service Program, Center for Disease Control andPrevention suggests that there is an increase in CWP among US coalminers which is associated with exposure to excessive amounts of respirable crystalline silica (Laney et al., 2012). Thus, NIOSH recommends(National Institute of Occupational Safety and Health, 2011) limitingrespirable coal mine dust exposure to a time-weighted average concentration(10 hour day during a 40 hour week) of 1 mg/m3 as opposed tocurrent value of 2 mg/m3. Similarly, for the same time period, respirablecrystalline silica would be limited to a time-weighted concentration of0.05 mg/m3. To maintain these reduced standards and annual coalproduction of over 1.1 billion (yearly average from 2007 to 2012)short tons (United States Energy Information and Administration,2013) ef fi cient and sustainable dust control technologies need to bedeveloped.A common approach to controlling the dust aerosol around aminingmachine such as continuous miner (CM) is to wet the dust particlesthrough the use of wetting fl uids (mainly water), increase their weightand facilitate their settling. （连续采煤机使用润湿液体，主要是水，来湿润煤体，控制粉尘）Other approaches include fl ooded-bed wet scrubber （湿式除尘器）and dilution through appropriate ventilation. Laboratory studiesof CM wet scrubbers (Gurley et al., 2012) estimated the percentage ofrespirable dust sucked into them to be about 30% while the scrubber suctioninlets are outside the box-cut. The remaining 70% suspended in the air can travelout-by the wet scrubber to reach the continuous miner(CMO) and haulage unit (HUO) operators and workers downwind ofthe miner. One would intuitively expect that the capture ef fi ciency ofthe total dust into the scrubber would be very high if air fl ow into theface and scrubber air fl ow are similar for a blowing ventilation system.However, some of the coarser dust particles settle down before gettingto the scrubber while a large amount of fi ne respirable dust remainssuspended in the air and are not sucked into the suction inlets. The suctiondistance around the suction inlets is estimated to be less than0.3 m based on fi eld observations. Scrubber air fl ow capacity is satis fi edthrough air recirculation and sucking air through other areas as determinedby CFD modeling (Chugh et al., 2011).Therefore, it is expected that only about 30% of the respirable dust enters the scrubber while the remaining 70% remains suspended in turbulent air in recirculationaround the mining machine while making relatively shallow cuts up toabout 3.6 m deep. In extended cut faces where the scrubber helps todirect air into the face as the cut is extended and the scrubber is locatedwithin the box cut, the capture ef fi ciency for total dust could approach70% and 30% of the respirable dust may remain suspended or bypassthe scrubber. It was estimated that there is only 10–25 s of time inwhich dust particles must be wetted for engineering controls to be effective.This was based on a CFD modeling review of air velocity vectors inthe face area (Kollipara et al., 2012) and air traveling from the face towardsthe CMO and HUO locations.it is hypothesized that Scienti fi c understanding of the wetting, physical and chemical characteristics are needed for improved wetting of dust particles, and 2) additional strategically located water sprays on the CM body are required for more opportunities for the airborne dust to be wetted in the face area.Coal is a complex mixture of organic and inorganic fractions (O'Keefeet al., 2013). Physical and chemical properties of coal particles de fi ne itswetting characteristics. Quartz which is an important mineral presentin coal is generally hydrophilic（亲水的）and compared to coal samples itis often more concentrated in roof and fl oor samples (Dai et al., 2014;Organiscak et al., 1990). A major portion of quartz dust reported in airbornecoal dust samples is liberated from cutting rock (Organiscak et al.,1990). This fi nding was also reported by Schatzel, 2009 through geochemical analysis.Surface properties are important from dust wettability point of view（表面性质）(Al-Taweel et al., 1986; Srikanth et al., 1995; Yang et al., 2010). Bulk andsurface properties of coal are heterogeneous naturally（表面性质是异构的）and may be further modi fi ed due to the introduction of frictional and thermal energiesduring the cutting process. Therefore, wetting characteristics wouldbe also expected to change. Oxidation of coal increases the coal hydrophilicity (Fuerstenau et al., 1988; Pawlik et al., 2004).（煤中氧气增加了煤的亲水性）Furthermore, contaminantsand the presence of water and other ions (Fubini, 1998) mayalso alter surface properties. In addition to the particle size (Li et al.,2013; Yang et al., 2010), particle fractal dimension (Li et al., 2013) mayalso affect the wetting characteristics with mixed results reported todate. （污染物、水、颗粒大小、颗粒形状都会影响湿润特性）Yang et al. (2010) reported that fi ner particles contain higher surfaceenergy and form a thin air fi lm around the particle which affectsits wettability（颗粒越小表面能越高，在颗粒表面形成的薄的空气膜会影响润湿性）. Carbon content (Yang et al., 2010) increase with decreasingparticle size may affect wettability. Severity of the CWP varies withcoal rank (Page and Organiscak, 2000) and coals with higher volatileyield are more hydrophilic（挥发分越高的煤亲水性越好）. Li et al. (2013) asserts that volatile gases form a thin fi lm around particles (particularly fi ner fraction) that may prevent them from wetting.（挥发性气体形成薄膜会阻止煤颗粒的润湿）Since wettability is a complex mechanism, laboratory wettabilitytesting “as an index”may be appropriate for designing engineeringdust controls. The index may also be used to assess wetting mechanismsin airborne dust. Wettability testing in the past has measured eithercontact angle（接触角）or behavior of particles at the liquid/gas interface (Chander et al., 2007). Conventional contact angle measurementtechniques are impractical for fi ne particles (Yildirim, 2001)（传统的接触角测量技术对微粒是不切实际的）. However, speci fi c particle size data was not reported in the paper. Contact angle also changes with time since droplet volume may recede depending on surface irregularities, roughness, contaminants and electro-static charges（接触角随时间会发生变化）. Thus, contact angle cannot be used directly to estimate the particle wetting characteristics. A few wettability methods estimate the sink time and wetting rates (Draves and Clarkson, 1931; Glanville andHaley, 1982; Kost et al., 1980; Mohal and Chander, 1986; Walkeret al., 1952) but none of them replicates the dynamic-wetting processof dust in the face area. In addition, the experimental time is hourslong and the data cannot be used directly to guide the development ofthe engineering controls. In view of the limitations of existing techniques,alternate techniques were used that attempt to develop wettabilitydata in physically realistic more underground mine environments.（需要试验新的技术来研究润湿数据以切实适应井下煤矿环境）Physical and chemical characteristic data related to coal dust wettingare limited for Interior Coal Basin coal mines (Chugh et al., 2011). Severalof the mines are faced with dust control problems (Chugh et al.,2011) due to: 1) high production rates of 1500–2000 t per unit shift,2) 15–20% out-of-seam mining dilution (with roof and fl oor material)and 5–10% in-seam dilution (partings within coal seam) that containhigh quartz content (Patwardhan et al., 2010), 3) longer holes(1.8–3.0mlong) for roof bolt support resulting in quartz-rich dust generation,4) super-section mining geometries with intake air coming intoone end of the section and traveling into the other section (polluted airfrom one section travels into the other section), 5) inadequate characterizationof quartz in coal seams and immediate roof and fl oor strata,6) improper cutting sequence, 7) inadequate ventilation and controlmeasures, 8) longer shift duration and 9) switching off scrubbers during the cutting process. Therefore, this research is considered important for developing engineering controls for coal and quartz dust control in coal mines.（需要进行粉尘控制的几种煤矿）Study areaThis study is based on the data for 11 cooperating mines from theInterior Basin. The following description of Illinois Basin coal geologywas modi fi ed from United States geological survey professional paper1625-D (Hatch and Affolter, 2002). Fig. 3 shows the stratigraphiccolumn of the Illinois Basin. Coal-bearing rocks in the Illinois Basinwere deposited in the Pennsylvanian age about 325 to 290 Ma ago.The Pennsylvanian rocks have three groups: Raccoon Creek Group,Carbondale Group or Formation, and the McLeansboro Group. The Pennsylvanian rocks have a maximum thickness of about 750min southeastern Illinois and generally thin toward the north, northwest, andnortheast. About 90–95% of the Pennsylvanian rocks are clastic rocks. Inthe lower part of the section, quartz rich, pebbly sandstones commonlymake up 60% of the total thickness. The rest of it is made up of siltstoneand shale containing less than 1% limestone. Sandstone makes up 25%of the total thickness in the middle and upper parts of the section, andshale（页岩）and claystone form 65–70% of the upper parts of the section. In general,5–10% of the upper two thirds of the section is limestone（石灰岩）. The Carbondale Formation or Group contains the principal economic coals in the Illinois Basin, including the Davis, Dekoven, Colchester, Survant, Spring fi eld, and Herrin Coals. In Indiana, the Dugger Formation of the Carbondale Group contains the Hymera and Danville Coal Members. In Illinois, the Danville Coal Member is the only economically important coal in the McLeansboro Group. McLeansboro Group coals above the Danville in Illinois and Indiana are not as thick nor as extensive as the coals in the underlying Carbondale Formation or Group. In western Kentucky, the McLeansboro Group contains three important commercial coals, the Paradise, Baker, and Coiltown coals.。