Liubavina V. A. – Kayerkan Coal Open Pit Mine MMC Norilsk Nickel JSC Polar Branch, Norilsk, Krasnoyarsk region,
the Russian Federation. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Contour blasting with the method of “protective layer” at subroof zone breaking with horizontal blastholes allows shaping
a buffer layer in the process of blasting with 0.8–0.9 m thickness, which undertake load from contour-hole charges and
explodes with maximum possible delay against the latter. Near contact-split zone is necessary to keep rock roof from
contour charges blasting. It is stated that with decrease or increase of normal release charge mass the indicator of
explosion effect decreases and increases correspondingly, i. e. the value of calculated specific consumption of explosives
depends on the indicator of explosion effect. It is covered by the introduction of the function of the indicator of explosion
30 «Известия вузов. Горный журнал», № 1, 2017 ISSN 0536-1028
effect in calculation formula. In the course of the investigation around 360 m of upper layer were broken (in roof – by
stepped face) with the use of the given method. Positive results of experimental and industrial testing have allowed
recommending the given method to use at all open pit mines of mining metallurgical company Norilsk Nickel.
Key words: contour blasting; buffer layer; near contact-split zone; blasting cone; the function of explosion effect indicator;
relieving charge; “protective layer”.

REFERENCES
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