Coal remains the most essential fossil energy source in China, with production from underground coal mines accounting for more than 80%. In underground coal mining operations, dust is a pervasive and hazardous material that can significantly compromise the safety and health of miners. High dust concentrations are associated with an increased incidence of pneumoconiosis and a heightened risk of catastrophic events, such as coal dust or gas explosions. The primary source of dust is the cutting processes of excavators and roadheaders during the extraction of coal and rock. Therefore, it is essential to comprehensively elucidate the mechanism of dust generation during cutting and heading operations for effective dust control in underground coal mines.

This paper presents an overview of the latest research developments in the field of dust generation, with a particular emphasis on three key areas: the behavior of dust generation during cutting, research methodology, and influencing mechanisms. First, regarding the behavior of dust generation during cutting by excavators and roadheaders, researchers have proposed several theoretical models to elucidate both the fragmentation processes of coal and rock bodies and the generation of dust under the influence of cutting. These models are based not only on the principle of energy conversion but also on the influence of the geometry of the cutting pick during the dust generation process. This provides a solid theoretical basis for understanding the physical nature of dust generation. Regarding the research tools employed, researchers have simulated the dust generation phenomena when mining machinery cuts coal and rock bodies through physical experiments conducted on self-designed experimental platforms. Researchers have also conducted numerical simulations using finite element or discrete element methods. These advanced experimental techniques elucidate the actual cutting conditions and offer a robust analytical tool for investigating the dust generation mechanism in depth. Additionally, this study provides a comprehensive analysis of the mechanisms influencing dust generation during cutting, examining both internal and external factors. These factors include the physicochemical properties of coal and rock, such as coal rank, moisture content, pore characteristics, strength, and brittleness, as well as the parameters of the cutting conditions, such as cutting depth, advance speed, drum rotation speed, and the morphology and arrangement of picks.

Current research on the dust generation mechanism during cutting reveals several contradictions. Existing models often rely on simplified assumptions, neglecting the anisotropy of coal and the actual cutting conditions in the field, leading to discrepancies between the calculated results and experimental observations. Moreover, existing experimental platforms struggle to accurately replicate the motion of the cutting pick during actual operations. Although many studies have focused on the properties of coal and rock and dust characteristics, some of the conclusions are conflicting. Future research should prioritize the construction of full-scale experimental platforms and the development of high-precision monitoring technologies. Comprehensively investigating the dust generation characteristics of complex coal seams and quantifying the energy conversion mechanisms during the cutting process are crucial. These efforts are essential for improving the efficiency of cutting operations and achieving more effective dust control.

Dust is easily generated in all parts of the mining process, which can cause dust explosions and lead to occupational pneumoconiosis in workers. Therefore, dust reduction is crucial in mining operations and plays an important role in protecting the environment and worker health. While traditional chemical dust suppressants provide short-term effectiveness, they pose considerable challenges. These include poor resistance to natural degradation, low environmental performance, and the risk of secondary pollution of soil and water sources, creating a growing demand for sustainable alternatives. To address these challenges, the authors proposed the idea of using microbial fermentation to synthesize biological dust suppressants.

To enhance the scalability and efficiency of microbial fermentation dust suppressant (MFDS) production, this study used a self-developed experimental device for fermentation and synthesis of biological dust suppressants. Six straight-blade disc paddles (6S-DR), six semicircular-blade disc paddles (6S-SDR) and four inclined straight-blade paddles (4-IR) were selected to design eight mixing combinations. Numerical simulations were performed to analyze key parameters, such as the matrix flow field velocity, turbulent kinetic energy, gas holdup, and stirring power. In addition, experimental tests were conducted to validate gas holdup and MFDS yield under different conditions. Furthermore, MFDS solutions of three purities, acid precipitation, single-stage ultrafiltration, and two-stage ultrafiltration, were characterized using liquid chromatography-mass spectrometry (LC-MS). MFDS was conducted using an LC-MS system. Tests for interfacial performance and wettability of MFDS were also performed to assess its dust suppression capabilities at different purity levels.

The results indicated that the stirring combination, using four oblique straight paddles, formed an obvious liquid circulation area. Adding an extra layer of paddles further expanded this area, enhancing heat and mass transfer. Stirring combination H demonstrated smaller liquid surface fluctuations and a more uniform distribution range of turbulent kinetic energy. These features increased dissolved oxygen levels and improved gas-liquid mass transfer, fostering microorganism growth. Consequently, stirring combination H achieved better substrate homogenization and delivered better fermentation performance under identical conditions.Interfacial performance tests revealed that when two-stage ultrafiltration was used, the critical micellar concentration of the bioreactor solution decreased to 22.65 mg/L. The higher the purity of the MFDS solution was, the smaller the critical micelle concentration of MFDS, and the viscoelastic modulus stabilized with increasing concentration. The ultrafiltration technique had a greater effect on the MFDS viscoelastic modulus, but the number of ultrafiltration cycles had a smaller effect on the viscoelastic modulus. The viscoelastic modulus stabilized as the concentration increased. Moreover, wettability tests indicated that the two-stage ultrafiltration purification improved dust suppression efficiency, achieving the shortest dust settling time of 67 s and remarkable wettability performance. Considering the results of the surface interface performance and wetting performance tests, the dust suppression performance of the two-stage ultrafiltration MFDS was superior.

This study investigated large-scale synthesis methods for biodust suppressants, focusing on matrix homogenization to increase production efficiency and scalability. This approach addresses key shortcomings of traditional chemical dust suppressants, including poor degradability, low surface activity, and environmental harm. By overcoming these issues, this study offers a meaningful solution to reduce dust pollution, protect the environment, and improve the occupational health of miners. Meanwhile, this study provides valuable theoretical guidance for the efficient development of green and environmentally friendly biological dust suppressants.