### Dustproof Technology  
Mine dust is one of the main causes behind the disasters in coal mines. Over years, a great deal of importance has been paid to the prevention and control of mine dust. Extensive studies have been conducted domestically and abroad to find effective solutions to minimize the negative impacts of the mine dust. At present, coal mines at home and abroad mainly use coal seam water injection, spray, dust collector, ventilation, chemical dust suppressant and other dust-proof technologies. 1. Coal seam water injection  
Pre-wetting the coal seam through the coal seam water injection technology is the most effective and basic dustproof measure for the working face. Studies from the former Soviet Union have shown that when the moisture of the coal body increases by 1%, the amount of dust generated during coal seam mining can be reduced by between 60% and 80% in quantity [16]. At present, it has been widely implemented across the whole country. The main state-owned coal mine which adopts the water injection treatment accounts for more than 40% of the total coal mining face, with a 7% to 50% dust reduction rate. 2. Spray dust reduction  
The United States, the former Soviet Union and Germany have also successively applied or experimentally studied the effect of high-pressure water spray on reducing the amount of respirable dust generated during the mining. The high-pressure water-assisted cutting technology for long-wall working faces tested and studied by the Pittsburgh Research Center of the US Bureau of Mines can significantly reduce the amount of respirable dust generated during coal cutting when the working water pressure is 12.7 MPa. The former Soviet Union Coal Mine Machinery Design and Research Institute has developed a complete set of TKO-CBO equipment for high-pressure water spraying of coal shearers. The former West Germany also tested the effect of high-pressure water spray on the wetting and settlement of dust in the drum storage and cutting area in the Walsum mine. The test showed that under the condition of working water pressure of 6-6.5 MPa, the average dust reduction could reach between 30% and 35% around the shearers. Other nations such as Australia and the United Kingdom are also experimenting with high-pressure spraying for shearers. In China, technologies such as negative pressure secondary dust reduction, spray suction combined with dust reduction have been researched in the spray dust reduction and have been tested and promoted in many coal mines. The spray dust reduction technology of the roadheader is divided into two types including the internal spray and the external spray. The internal spray technology is to install the nozzle on the cutting part of the roadheader, with the water mist sprayed from the nozzle directly, aiming to suppresses the instantaneously generated dust when the roadheader is operating. The external spray technology captures the suspended and free dust in the roadway. Spray dust reduction technology is widely used in coal mine excavation operations. At present, the dedusting water used in coal mines is recycled after the simple treatment of underground sewage. Therefore, some impurities such as coal slime tend to be mixed with the water, which can plug the nozzles with small cavity and affect the dust removal. At the same time, the large amount of water mist generated tends to affect the driver's sight during tunneling operations and deteriorate the working environment. 3. Dust collector for dust removal  
Dust collectors include the mechanical dust collectors, dry filter dust collectors, wet dust collectors and electrostatic precipitators. Poland has developed a comprehensive dust-proof technology for the excavation face that uses the eddy current air duct to control the dust diffusion of the tunneling head and uses the composite dust collector to purify the dust-laden airflow.