Worn cutter picks as a secondary resource for manufacturing modular cutting tools for shearers

Abstract

Upon agreement with a Kuzbass mine’s management, the worn picks of shearer JOY 4LS-20 were collected to manufacture load-bearing members of modular cutter picks. Four innovative picks were set on the cutting drum of the shearer and their performance was observed. The mine trials proved the theoretical hypothesis on potential recycling of the worn traditional picks as a secondary scrap metal for manufacturing modular tools. Three out of four experimental picks were run for 35 days on the shearer which produced 55 Kt of broken rock mass within that space of time. Due to the inconsistency of the working coal seam thickness, the overcut of the shearer was to 0.2 m deep in the middle of the longwall floor composed of grey sandstone having the hardness factor of 5–6 on the Protodyakonov scale. The mine managers’ fears concerning attachment unreliability of the cutting modules, their falling out and expanding of screws remained unconfirmed. Only one pick was damaged with tearing-off of the attaching ring. Inspection of the load-bearing members of the modular picks after trials exhibited their insignificant operational wear at the level of 0.5–2.5% of their initial mass. The length and the attaching diameter of the members remained nearly the same, which proves their long-term usability in a set of the modular cutter picks in underground coal cutting. The mass of the load-bearing module is 80% of the whole tool, which allows considerable reduction (to 5–7 times) in metal consumption of coal shearing with redesign and recycling of the worn tools on the ground of modularity.