Abstract:

Nowadays, coal mining is primarily carried out by underground method. The shearer is the main equipment used in underground coal mining in developed mining countries and it is gradually applied in underground coal mines in Viet Nam. With coal-cutting machines, using the cutting drum is applied mainly because of its simple structure, high productivity, and reliability. However, during the coal-cutting process, the fine coal content of about 40÷50% of the total mining output causes dust generation as well as energy consumption because the coal is cut too small. According to previous studies, this problem is solved by increasing the thickness of the slices, which is achieved by using larger drums with large cutting teeth, and in combination with increased speed movement of the stage machine. This increases machine size, large investment costs and reduces machine flexibility due to the tight space of mining areas. Through the research of previous authors, it is possible to increase the cross-sectional area of the slices by forming slices in pairs and groups, and at the same time enhance the failure by tensile stress instead of mostly compressive stress. In addition, the overlap of stresses around the slice, when using the coal-cutting teeth group, also reduces the cutting force on the cutting teeth. In this study, a new solution is proposed to increase the height of the cutting teeth and the width of the cutting step without increasing the local load acting on the cutting teeth by combining the cutting teeth in groups thereby reducing dust, increasing the particle size of the cutting teeth coal, reducing specific energy and increasing cutting capacity of the coal cutting machine.