NUST MISIS’ College of Mining, Moscow, Russia

I. N. Savich, Doctor of Engineering Sciences, Professor, rtp_msmu@mail.ru
V. I. Mustafin, Associate Professor, Candidate of Engineering Sciences
A. O. Savich, Student

When justifying parameters of gravity ore flow in mining systems with caving of ore and enclosing rocks, as well as when calculating ore loss and dilution, different scientists suggest different versions of visualization of the process. However, none of them has succeeded so far in theoretical justification of the shape of an outflow. Therefore, the outflow shape is determined from the experimental data with the assumed equality between the volume of a granular body outlet from a model and the adopted approximate outflow shape. This article describes the studies on ore outflow and the results of geomechanical stability assessment of an extraction block bottom at different heights of caved ore and rock columns with determination of ore loss and dilution. The influence of rock pressure on the formation and parameters of an outflow shape under caved rocks is examined. It is possible to state that, as the experiments have proved, in uniform sequential ore drawing, outflows from drawbells have complex and various shapes, and there is no basis for expectations that outflows can have any regular shapes in the nonuniform process of ore drawing, which always happens in real-life production. Physical simulation and observation over the sequence of outgoing markers from the model prove that soon after beginning of the outflow, the order of the marker departure from the model is broken, and, because of the shape deformation of the flow, the upper embedded markers often go out earlier than the lower embedded markers.

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