## 3 Application
### Application of Foam Dust Reduction in Zhangcun Coal Mine  
Zhangcun Mine working face 2601 lane is located on the east side of 2601 wind lane, with two lanes arranged in parallel with a distance of 230 m (middle-middle). The opening is located at the north side of Section II of the +480 m horizontal belt lane, and is arranged along the coal seam floor, with a design length of 1819.5 m (In the middle of the digging and cutting hole--in the second section of the +480 m horizontal belt lane). Based on the field conditions, the air volume of the air duct is as high as 800 m\({}^{3}\)/min. When the coal is cut, the pulverized coal is scattered and the pulverized coal is lifted up instantly. The wind tends to affect the spray of the foam on the coal wall. Despite that the dust suppression effect is affected, this application can still improve the working environment of the face driver to some degrees. In the absence of any measures, the visibility in the working face space is seriously jeopardized in the process of coal cutting. Figure 3: Distribution of foam dust reduction coal mines. The driver can only operate on one piece of coal and wait for the coal powder to dissipate before cutting another piece of coal, which greatly lowers the work efficiency and affects the progress of excavation. Turning on the internal and external water spray of the roadheader had limited effects on this situation. However, the application of the foam has been proved to be effective in the dust reduction. The specific effect of foam dust reduction is described below based on the measured data. Data was collected at multiple sample points. According to the data analysis, the dust reduction efficiency of foam dust reduction technology in Zhangcun Coal Mine's 2601 roadway excavation face was obtained. Firstly, the foaming agent and water were mixed in a ratio of 1:1, and then three sets of data were measured on the head of the roadheader, which were the total dust and breathing without any dust reduction measures, after water mist dust reduction, and after foam dust reduction. The dust concentration was compared and shown in Table 4.  
At the same ratio (1:1), the total dust and respiration dust concentrations were measured at the transfer point, 5 m after the transfer point, and 10 m after the transfer point, respectively. The data are shown in Table 5. (due to the damage of the water mist dust reduction facilities, the relevant data under the measures have not been measured). The water mist dust reduction in the table is the airborne internal and external spraying of the roadheader. The water consumption is generally about 10 m\({}^{3}\)/h, while the water consumption of the foam is 1.5 m\({}^{3}\)/h. Figures 4 and 5 show the concentration charts before and after dustfall, and Figures 6 and 7 show the comparison histograms of the dust-falling efficiency of water mist and foam at the driver. \begin{table}
\begin{tabular}{c c c c c c} \hline  & & **Total Respiable** & **Mineral Dust** & **Concentration of** & **Mineral Dust** & **Respiable Mineral** \\  & **Dust Concentration** & **Concentration of** & **Suspended Air** & **Dust in suspended** & **Supersded Air** & **Air after Foam** \\  & **mg/m\({}^{3}\)** & **Working Face** & **Dusting** & **by Water Mist** & **after Foam Dusting** & **Dust Reduction** \\  & & & **mg/m\({}^{3}\)** & **mg/m\({}^{3}\)** & **mg/m\({}^{3}\)** & **mg/m\({}^{3}\)** \\ \hline \multirow{4}{*}{measurement data} & 1629 & 622.5 & 1297.5 & 413.5 & 443.5 & 199 \\  & (10.20) \({}^{*}\) & (10.20) & (10.20) & (10.20) & (11.08) & (11.08) \\ \cline{1-1}  & 1197 & 353 & 952.1 & 347.5 & 373.5 & 196 \\ \cline{1-1}  & (10.23) & (10.23) & (10.23) & (10.23) & (11.10) & (11.10) \\ \cline{1-1}  & 1413 & 487.8 & 1124.8 & 380.5 & 408.5 & 197.5 \\ \cline{1-1}  & dust reduction efficiency (\%) & 20.4 & 22.0 & 71.1 & 59.5 \\ \hline \end{tabular} Note: \({}^{*}\)The time in parentheses is the measured data time.  
\end{table} 
Table 4: Comparison of dust suppression efficiency at roadheader drivers.