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[Display omitted] • The mathematical model of CFD-DEM calculation method was used. • The inhale and dust exposure characteristics of driver were analyzed. • Different area airflow patterns of bronchus were analyzed. • The deposition rate of different particle diameters were analyzed. To study the dust exposure law of the operator in the anchor digging working face, the CFD-DEM method was used to numerically simulate the dust deposition pattern in the bronchus of the anchor digging driver. The results show that the highest dust concentration in the vortex region of the anchor digging working face can reach 2364.76 mg/m3, seriously endangering the health of anchor digging driver. The average dust concentration in the respiratory hemisphere of the driver is 510.57 mg/m3, and the range of inhaled dust diameter is 0–60 μm in the breathing state of moderate labour. Over time, the deposition mass in the bronchial showed a pattern of rapid and then slow increase, which was consistent with the trend of the Boltzmann model. Increasing dust particle diameter was positively correlated with bronchial deposition rate and negatively correlated with alveolar deposition rate. Among them, 0–10 μm particles were deposited throughout the bronchus and a large number of particles were deep into the alveoli, with the alveolar deposition rate as high as 56.3 %, while the alveolar deposition rate for particles of 10–20 μm decreased to 20.4 %, and for particles larger than 30 μm, the effect on the alveoli was smaller. [ABSTRACT FROM AUTHOR]

• A multicomponent acid solution consisting of SDBS,BS-12, HF and C6H8O7 was used to acidifie coal samples. • Acidification treatment can promote the formation of oxygen-containing functional groups C O and C O. • Provide an effective method for realizing high-efficiency clean mining of coal. • The micro mechanism of wettability was explained using molecular dynamics software. In order to explore the influence mechanism of different surfactants on the wettability of coal samples acidified with multi-component acid solutions, the effects of multi-component acid solutions and surfactant composite acid solutions on the functional groups and microcrystalline structures of coal samples were studied. In this paper, a multicomponent acid solution consisting of sodium dodecyl benzene sulfonate (SDBS), dodecyl dimethyl betaine (BS-12), hydrofluoric acid (HF), and citric acid (C 6 H 8 O 7) was used to acidification and contact angle experiments on coal samples. Fourier transform infrared spectroscopy (FTIR) results show that acidification can promote the formation of C O and C O, and the synergistic effect of surfactant BS-12 on multi-component acid solution is more prominent. X-ray diffraction (XRD) results show that the variation trend of aromatic lamellar diameter L a of coal samples is consistent with the aromatic layer spacing d 002. Surfactants can slow down the damage of multi-component acid solution to the microcrystalline structure of coal samples. The change of contact angle shows that the instantaneous synergistic wetting effect of BS-12 is better than that of SDBS. At the same time, molecular dynamics simulation technology was used to verify the effect of surfactants on the wettability of multi-component acid solutions. Therefore, this study provides a feasible method and theoretical guidance for improving the efficiency of coal production and utilization through chemical means. [ABSTRACT FROM AUTHOR]