Increasing the content of coarse fractions in the mined coal mass by a combine using paired cuts

Abstract

The main volume of coal is mined underground using shearers. In modern shearers, auger actuators are mainly used, which are distinguished by the simplicity of design, manufacturability and reliability. However, in the process of separating coal from mass by cutting, the yield of fine grades is 40-50 % of the total production volume. Therefore, the search and development of technical solutions that provide an increase in the yield of large fractions in the process of coal mining with auger shearers is an urgent task. Traditionally, this problem is solved by increasing the thickness of the slices, which is achieved by installing cutters with a larger radial reach and increasing the shearer feed rate. An unconventional way to increase the cross section of slices by forming energy-efficient paired and group slices with mutual superposition of stress fields in the mass from the action of neighboring cutters is considered. The results of modeling the process of cutting coal confirm that an increase in the efficiency of destruction of the rock mass by the cutters of the auger executive bodies of the shearer can be achieved by a complex technical solution, including the formation of paired cuts and combined stress zones in the rock mass. As a result, the output of large fragments when cutting with paired cutters increases by 1.3-1.8 times compared with cutting with a single cutter.

Extraction of Inclined Exit Ledges in Coal Mines in Presence of Mobile Crushing and Conveyor Complexes

“…When extracting minerals from the deposit using a specific technological scheme that involves the MCCC as the destination, in combination with a mobile CBM for sequential mining on two horizons, it is crucial to consider all potential periods of inactivity of the mining and loading machine (20,21). The predicted mining time of the exit ledge and the evaluated range of operating productivity of the MCCC were determined based on the proposed approach for the conditions of the Angren coal mine (22,23).…”

“…The results of the calculations for establishing the excavator bucket fill factor during the formation of the exit scarp (21,30,31) are presented in Table 7. To fill the bucket with a cap in accordance with GOST R 55165-2012, the excavator at one digging run has a minimum required face height of 4m.…”