Blasting operations in mines generate significant amounts of impact dust, which poses a significant risk of pneumoconiosis and threatens workers' health. This also results in substantial direct economic losses annually, severely impacting China's pursuit of high-quality economic development. Existing ventilation and dust removal technologies have proven inadequate. Among various developed dust reduction methods, wet dust suppression technology has improved continuously. A key advancement is the use of ultrasonic atomizing nozzles, known for their low water consumption, effective atomization, and superior dust capture efficiency. Consequently, a dry mist dust suppression technology has been proposed to efficiently manage dust from mining blasting operations, improve working conditions in return airways, and safeguard the physical and mental health of workers. This study investigates the application of dry mist dust suppression technology in roadway-type mining faces of metal mines to achieve these objectives.

This study focused on a roadway-type mining face in a certain iron ore mine. The initial investigation involved analyzing the physical and chemical characteristics of dust generated during blasting operations, particularly examining mechanisms that influence its wetting properties. Dust samples were classified through flotation into hydrophilic and hydrophobic types. Further analysis was conducted on their wetting properties, surface morphology, particle size distribution, and surface pore structure to explore the physicochemical characteristics affecting dust wetting. Three types of ultrasonic atomizing nozzles were selected for testing their atomization characteristics under different pressure parameters using an atomization test platform. This study analyzes the influence of different air-water parameters on atomization characteristics and identified the optimal nozzle for dust reduction applications. Furthermore, a dry mist dust suppression device was designed and developed for use in mining. Field experiments evaluated dust distribution in return airways before and after blasting operations, with and without the application of mist spraying for dust suppression.

This research indicated that the impact dust generated during blasting operations was predominantly hydrophilic. The dust wetting properties were primarily influenced by factors such as particle size and surface porosity. Critical to the efficiency of dry mist dust suppression were the droplet size and quantity. The median droplet size D₅₀ showed an inverse relationship with the ratio of air pressure to water flow rate. Among the tested nozzles, SK-508, SV-980, and SV-882, the SK-508 ultrasonic atomizer exhibited the smallest average droplet size and consumed the least amount of water, thus conserving water resources effectively. Under conditions of 0.7 MPa air pressure and a water flow rate of 0.1 kg/s, the SK-508 demonstrated significant atomization effects, making it the optimal nozzle for dust suppression among those tested. Leveraging the advantages of dry mist dust suppression technology and the atomization characteristics of ultrasonic nozzles, a dry mist dust suppression device was developed. Field tests of the prototype demonstrated its notable effectiveness in reducing both total dust and respirable dust, achieving a high level of dust suppression efficiency.

A dry mist dust suppression device was developed to address the issue of dust in return airways, effectively managing both total dust and respirable dust in mining tunnels. It achieves efficient control of impact dust generated during blasting operations. This innovation provides a solid theoretical foundation for advancing the national green mining initiative and contributes to establishing a comprehensive technical system for dust control in mines.