## 7 Conclusions  
In an attempt to reduce dust concentration at an underground longwall face, the authors fabricated a full-size, physical model of a Joy 7 LS longwall shearer with an integrated flooded-bed dust scrubber. The physical model was installed in the longwall test gallery of the NIOSH Pittsburgh Research Laboratory to test its dust capture effectiveness. An air quantity survey was carried out to quantify the distribution of airflow in the longwall test gallery. The survey was performed at four different cross-sections along the face at a fixed face-air quantity for three different scrubber air capacities. A 3-D computer-aided design (CAD) model of the experimental gallery was created, and the validation of a computational fluid dynamics (CFD) model was performed using the survey results. The validation was carried out in two stages. First, a validation of the total quantity of air passing through each cross-section was performed, which resulted in a maximum deviation of 9.9%. Then, a more precise validation of the magnitude of the velocity vector at six points at each cross-section was performed, which showed a maximum 18.2% variation. The validated CFD model was used to analyze the effects of scrubber capacity and face air quantity on the airflow in the longwall panel. The model can be utilized further to understand the impact of the flooded-bed integration on dust reduction in a longwall panel. Conceptualization, T.N., J.S. and S.A.; Methodology, J.S. and S.A.; Software, S.A.; Validation, S.A., Formal Analysis, S.A. and J.S. ; Investigation, T.N., J.S. and S.A.; Writing--Original Draft Preparation, S.A.; Writing--Review and Editing, J.S. and T.N. ; Supervision, J.S. and T.N. ; Project Administration, J.S. and T.N. ; funding acquisition, J.S. and T.N. All authors have read and agreed to the published version of the manuscript. Figure 13: Comparison of airflow pattern in the longwall test gallery at three different face air quantities. Funding: Funding for this research was provided by the Alpha Foundation for the Improvement of Mine Safety and Health (grant number AFC113-10). We want to thank personnel from Joy Global, Inc. and the Tunnel Ridge Longwall Mine (Alliance Resource Partners, L.P.) for their guidance. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Acknowledgments: The authors want to thank the Alpha Foundation for the Improvement of Mine Safety and Health for funding this research. We would also like to thank personnel from Joy Global, Inc. and the Tunnel Ridge Longwall Mine (Alliance Resource Partners, L.P.) for their guidance. Conflicts of Interest: The authors declare no conflict of interest. References References  
* [PERSON] et al. (1997) [PERSON]; [PERSON]; [PERSON] Status of Dust Control Technology on U.S. Longwalls. In Proceedings of the 6 th International Mine Ventilation Congress, Pittsburgh, PA, USA, 17-22 May 1997; pp. 345-351. * [PERSON] and [PERSON] (2007) [PERSON]; [PERSON] Current Dust Control Practices on U.S. Longwalls. In Proceedings of the Longwall USA, Pittsburgh, PA, USA, 5-7 June 2007; pp. 1-12. * Fiscor (2019) [PERSON] _Coal Age_; Mining Media International: Jacksonville, FL, USA, 2019; p. 25. * U.S. Energy Information Administration (2018) U.S. Energy Information Administration. Annual Coal Report (2018). Available online: [[http://www.eia.gov/coal/annual/](http://www.eia.gov/coal/annual/)]([http://www.eia.gov/coal/annual/](http://www.eia.gov/coal/annual/)) (accessed on 5 May 2020). * [PERSON] et al. (2016) [PERSON]; [PERSON]; [PERSON] Continuous dust monitoring in headings in underground coal mines. _J. Sustain. Min._**2016**, _15_, 125-132. [CrossRef]
* [PERSON] et al. (1990) [PERSON]; [PERSON]; [PERSON] Dust Sources and Controls on High Tonnage Longwall Faces. _Soc. Min. [PERSON]. [PERSON]_**1990**, \(9\), 73. * [PERSON] and [PERSON] (2018) [PERSON]; [PERSON] Exposure to Harmful Dusts on Fully Powered Longwall Coal Mines in Poland. _Int. J. Environ. Res. Public Health_**2018**, _15_, 1846.