Improving the efficiency ofthe coal-cutting process by combining cutting teeth on the drum of the coalcutting machine used in underground coal mining

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 ofthe slices by forming slicesin 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 reducesthe 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 groupsthereby reducing dust, increasing the particle size
of the cutting teeth coal, reducing specific energy and increasing cutting
capacity of the coal cutting machine