Laboratory studies of the effect of the discharge funnel on the results of ore drawing

Abstract

Ore drawing from the mined-out space in the presence of surrounding rocks is one of the most critical moments, on which quantitative and qualitative ore losses depend. Some decrease in the quality of the mined ore at the final moment of drawing does not reduce the advantages of systems with mass caving and mass drawing, since the progress of enrichment technology allows for a more confident use of mass mining methods with subsequent processing of minerals at enrichment plants. The results of ore drawing are determined not only by the appropriate organization and control during this process, but also by the correct choice of individual design elements - the "ore drawing horizon". These design elements include the distance between the discharge funnels, the slope angle of the funnel walls, the diameters of the lower and upper bases of the funnel, the difference in marks between the "release horizon" and the undercut horizon, etc. When drawing through funnels of the same height, but with different slope angles, the rdrawing figure will be maximum for the funnel with the optimal angle slope. The transverse dimensions of the discharge figures depend not only on the physical and mechanical properties of the flowing bulk materials (or ore), but also on the nature of the funnel surface. The greatest extraction of pure ore, a later onset and a slow increase in dilution are characteristic of discharge through funnels with an optimal slope angle. The height of the discharge funnel (with an optimal slope angle and a constant height of the ore layer) cannot be arbitrarily large, since this leads to an increase in the distance between the discharge openings, isolated discharge and an increase in ore losses in the ridges. Conclusions made from experiments on ore drawing from a single opening are confirmed by experiments on discharge from a number of adjacent openings. The optimal slope angle of the funnel should be the starting point in determining the distances between the discharge openings.