Abstract
The object of research is a rock massif of iron ore, which is destroyed by an explosive located in deep wells. One of the most problematic places is ensuring uniform grinding of the rock massif during underground mining of mineral deposits at great depths. In the Kryvyi Rih iron ore basin (Kryvyi Rih, Ukraine) in underground mining let’s use the Ukrainian-made Grammonite 79/21 explosive, which provided an opportunity to obtain high-quality grinding of the ore mass to a depth of 1200 m. With a decrease in mining, these indicators deteriorate significantly, due to the manifestations of rock pressure, which leads to the overcoming of wells and increased specific charge for blasting. A comprehensive method is used based on an analysis of existing methods that affect the specific charge of an explosive. According to practice data, it is found that when using an emulsion explosive in mining operations, the specific consumption of an explosive decreases, while the cost of extraction decreases and the quality of grinding of the massif improves. However, due to the lack of a methodology for calculating the parameters of drilling and blasting operations, the «Ukrainite PP-1» emulsion explosive is not widely used. The development of the methodology taking into account the characteristics of the «Ukrainite PP-1» emulsion explosive will improve the extraction of ore mass. It is shown that the use of «Ukrainite PP-1» emulsion explosive leads to a decrease in the total length of wells by 35 %, and a decrease in production costs. This is due to the fact that the proposed method of calculation has the peculiarity of taking into account the specific costs of emulsion explosives obtained by pilot tests, in particular, the efficiency coefficient of emulsion explosives. Due to this, the costs of drilling and blasting work are reduced and it is possible to obtain a calculated economic effect from the introduction of this technology at the level of 0.6 c. u./t. The proposed pattern of drilling the massif by the downward fans, compared with similar known, can reduce the time for drilling and improve the grinding of the rock massif without changing technology.
Highlights
The underground mining of the Kryvyi Rih iron ore basin (Kryvyi Rih, Ukrainite PP-1» (Ukraine)), the extraction of minerals is carried out by traditional development systems using drilling and blasting operations [1, 2]
The Research Mining Institute of the State Higher Educational Institution «Kryvyi Rih National University» (Ukraine) recommends determining the least resistance line, taking into account the blasting direction, type of explosive and its uniform distribution in the massif ac cording to the formula [13, 18]: b⋅Δ
With known specific charge of the explosive on the blasting – q, the least resistance line is deter mined by the formula [1, 7]: where Wf – LRL, which is determined by the formula (4); Ks – the coefficient of energy intensity of breaking of strained rocks, equal to the ratio of the specific charge of the explo sive, which are set taking into account the depth of mining works and the size of the clearing space qs to the EE specific charge, which are determined by the strength of the rocks qf
Summary
The underground mining of the Kryvyi Rih iron ore basin (Kryvyi Rih, Ukraine), the extraction of minerals is carried out by traditional development systems using drilling and blasting operations [1, 2]. For drilling of a mountain massif, НКР-100МПА or КБУ (Ukraine) drilling ma chines are used, which require considerable time to drill wells in the refining unit This leads to the destruction of the drilled wells of the total volume according to the practice of 10–15 %. In order to reduce the losses of drilling wells and the undermining of the massif is performed in two or more stages, this leads to an increase in time for the unit and the reduction of labor productivity in the system. The solution to this problem is possible by reducing the volume of the cleaning unit, the use of self-propelled drilling equipment and more efficient explosives. TECHNOLOGY AUDIT AND PRODUCTION RESERVES — No 6/1(44), 2018, © Stupnik M., Kalinichenko V., Rymarchuk B., Pysmennyi S., Fedko M., Kalinichenko E
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