Abstract
When underground mining of Ural copper deposits with a chamber mining system, an urgent scientific and practical task is to increase the productivity of loadingdelivery machines for the ore drawing from secondary chambers. The technogenic disturbance of the massif of such chambers in combination with the non-alternative use of a blasthole ring scheme of breaking leads to an increased output of oversized fractions. With an increase of oversized ore output, operating costs for the drawing and delivery of ore increase, tire wear, fuel and lubricants consumption increases. In this article, the possibility of reducing the oversize ore output in secondary chambers by using counter blasting of the breaking layers is considered. As a result of the research, the parameters of effective counter blasting with blasthole ring charges were established, namely, the distance between the working faces in the chamber, the angle of ore pieces meeting and the line of least resistance.
Highlights
Mining of thick ore bodies of copper deposits in the Urals (Gayskoye, Sibayskoye, Oktyabrskoye, Uzelginskoye, etc.) is mainly carried out with chamber mining systems with solidifying filling and the use of self-propelled equipment for ore drawing and delivery [1]
In work [4] it is noted that the value of the oversized ore yield for copper deposits increases 1.3-1.5 times for every 300-400 m increase in the depth of mining
A promising direction for improving the quality of ore crushing in secondary chambers with a level-chamber system with a filling is the use of counter blasting of blasthole rings, in which additional crushing of colliding pieces of ore occurs [6]
Summary
Mining of thick ore bodies of copper deposits in the Urals (Gayskoye, Sibayskoye, Oktyabrskoye, Uzelginskoye, etc.) is mainly carried out with chamber mining systems with solidifying filling and the use of self-propelled equipment for ore drawing and delivery [1]. In the ore pillars under the influence of rock pressure, blastholes are often disturbed and lost. Under these conditions, there is an increased yield of oversized ore (1.3-2.5 times higher than in the chambers of the first stage) during ore breaking [2] and, as a result, a significant decrease in the productivity of load-haul-dumpers (LHD) [3] in drawing and delivery of ore from the chamber. Many parts of the ore bodies are broken by cracks filled with chlorite-sericite shales, which are prone to swelling upon contact with water, as a result of which, already drilled blastholes often turned out to be blocked [5]
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