Kovdor Ore Dressing and Processing Enterprise

Kovdor, Russia

Kovdor Ore Dressing and Processing Enterprise

Kovdor, Russia
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Fokin V.A.,Russian Academy of Sciences | Togunov M.B.,Kovdor Ore Dressing and Processing Enterprise | Semkin S.V.,Kovdor Ore Dressing and Processing Enterprise | Shitov Yu.A.,Kovdor Ore Dressing and Processing Enterprise
Gornyi Zhurnal | Year: 2013

Crushing quality of blast rock mass is the main indicator of drilling and blasting operations' efficiency under open-pit mining conditions. Thus, there are shown the following key parameters, characterizing the crushing quality: -size of an average piece of rock; -yield of fractions, which size exceeds maximum permissible value (oversize yield); -yield of fractions, which size doesn't exceed the target value. Regular measurements of granulometric structure of blast rock mass have the following peculiarities: - provision of monitoring of the basic trends in crushing quality change; - timely responding to quality degradation and estimation of new designs' efficiency of charges or new types of explosives, compared to the previously used ones. At the same time, comparison of crushing quality will be reliable in case of methodical uniformity in initial data obtaining on the foregoing crushing quality parameters. According to this, new and more informative criteria should be used. This makes it possible to reduce all possible options of block blasting (various types of explosives, different diameter and design of borehole charges) "to a common denominator". For this purpose, the authors proposed the new criterion of crushing quality of blast rock mass and relevant scale of quality classification, based on this criterion. Thus, the horizontal axis of the scale can be different, depending on the purpose of the analysis: for example, specific energy of different type explosives (efficiency is analyzed by comparison of previously used and new explosives with same diameter of borehole charges and same initiation method); diameters of borehole charges (impact of charge diameter is analyzed for crushing efficiency under similar initiation method and same type of explosive); chronological dates (months and years, if chronological changes for a certain period of time are analyzed). Case studies of proposed technique are presented to make the crushing quality assessment of blast rock mass, using borehole charges of different diameters and initiation methods as well as some aspects of an average blast piece of rock, based on uniqueness of solution principle.


Fokin V.A.,Russian Academy of Sciences | Togunov M.B.,Kovdor Ore Dressing and Processing Enterprise | Melik-Gaykazov G.V.,IMS LLC | Ovyan A.I.,Maksam Russia LLC
Gornyi Zhurnal | Year: 2013

Nowadays, application of emulsion explosives at open-cast mining operations become almost universal. Rather fast distribution of these explosives in mining industry is caused by the following undoubted advantages before factory industrial explosives: significantly lower price (cost price) (1,5 - 2 times); water proofness; high level of mechanization and automation of works; safety of preparation and usage. At the same time, the monitoring system of emulsion explosives quality was developed by the designer of formulation and technology of preparation of these explosives. This system should be strictly observed by the manufacturer. However, the final objective estimation of emulsion explosives quality is possible to be done only with measurement of actual detonation rate of emulsion explosives. In connection with this, authors offered a methodology of analysis of results of polygon and intra deep hole measurements of detonation rate. This methodology makes it possible to determine the size of actual specific energy release. More informative quality control of emulsion explosives is proved both in the course of their technological application, and at the stage of tests of new formulation structures. This article gives the examples of practical usage of an offered methodology. Besides, regular measurements of detonation rate make it possible to establish a nature of changes of specific energy release at explosion of various diameter deep hole charges. At the same time, it is also possible to choose the parameters of placement of these charges at the mass explosions design more reasonably.

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