132 has been noticed in Poland. As reported in (Global Green House Gas Emissions Data, accessed on 15th June 2021), there are several factors contributing to this phenomenon as increasing longwall lengths, mining speed, and increasing saturation of coal seam related to deeper exploitation of the raw material (e.g. in some Polish coal mines coal is extracted from 1000 m below the ground level (Dreger, 2019). Characteristic of VAM includes: dust load, particle size, mineral matter of the dust, variation in methane concentration and flow rate, possibility of existence of other gaseous pollutants as H2S or SO2 (Su et al.,2008, Hinde et al., 2016), He, H2, HCN,NH3, NOx, H2S, SO2 (Setiawan et al., 2014) and high amount of water (Fernandez et al., 2015). The fresh air composition supplied to the mine undergoes unfavorable changes, which are the result of mixing gases flowing out of rocks and gases resulting from technological processes and oxidation processes with the pumped air. The temperature of the air rises while it comes into contact with the rock mass and with power devices. Its humidity is also increased. It is worth mentioning, that the availability of detailed data of the VAM characteristics is poor and insufficient. The indicated parameters characterizing ventilation air cannot be generalized on the scale of the mining region or the country. Detailed data is important for selecting the appropriate technology for VAM disposal. A good example is an article (Su et al., 2008) that summarizes the results of the three-month tests of measurement results of compositions of ventilation air emitted to the atmosphere from four gaseous Australian mines. It was shown that the measured values were different between the examined objects but also depend on the currently conducted mining works (see Table 1). Table 1. The chosen data of VAM at different coal mines. 1 another gases as CO, H2S, SO2 were not detected. As reported by another sources the VAM flow rate can achieve even 600 m3 /s (Bae et al., 2020; Tremain et al., 2019) and daily dust loading can reach 232 kg (Bae et al., 2018). It should be considered, that all mentioned parameters generate huge technical problems in the Parameter1 Australia Turkey Mine A [3] Mine B [3] Mine C [3] Mine D [3] Kozlu mine – Turky [14] Flow rate [m3/s] 230-260 120-195 370-390 200-230 85-97 Relative humidity [%] 100 85-100 74.5-83.5 73-99.8 No data Dust loading [mg/m3] 0.13-4.47 0.25-3.87 0.67-3.82 0.21-3.19 No data Methane conc. [vol. %] 0.08-0.92 0.16-1.4 0.04-0.19 0.32-1.68 0.6-0.9
RkJQdWJsaXNoZXIy MTM0Mzk2