IM UB RAS, Yekaterinburg, Russia:

E. P. Artemiev, Senior Researcher, C. Eng., e-mail: lubk-igd@mail.ru

A. V. Yakovlev, Head of the Laboratory Open-Pit Geotechnology, C. Eng., e-mail: yakowlev.igd@mail.ru

E. S. Busargina, Engineer, phone: +7 (343) 350-54-11

JSC “EVRAS KGOK”, Kachkanar, Russia:

V. G. Bushel, Chief Engineer, phone: +7 (343) 414-76-02

A. V. Dubskyh, Chief of Drilling and Blasting Operations, phone: +7 (343) 414-73-26

The potentialities of pit edges construction on increasing their slopes are examined as an example of the JSC “EVRAS KGOK” Western open pit, exploiting the western body of titanium-magnetite ores of Gusevogorsky deposit. The calculations of stable slope angles of 15 meters working and 30 meters doubled benches in the utmost contour by different pitch angles of slackening surfaces aside the recess are cited in terms of studying the orientation and strength properties of surfaces weakening in the lower area of extinguished benches around the whole open pit perimeter. The scheme of open pit zoning with different after high walls conditions is drawn up. Three areas with designed stable slope angles of the benches having the 15 and 30 meters height are marked out. The arrangement of 30 meters benches into the utmost position was carried out with forming cut off slots on each 15 meter working bench independently, that made it possible to rise the resultant extinguish angles of doubled benches by 2–8° on forming the 3 meter shelf between them. For decreasing the intensity and width of the after contour mass fault area, the nearcontour pillar working off was conducted by belts with less than 25 meters width, while the rock mass crushing quality was increased. This operation was carried out employing multicharged short-delayed blasting schemes (MCSDB) with increased slowing-down time intervals between charges in the line up to 100–109 ms and up to 67 ms between the lines that assured independent crushing charges operation on face rock mass breaking. The rising of bench slopes and high benches angles of repose made it possible to increase the designed depth of OJSC “EVRAS KGOK” Western open pit by 65 meters without extra extinguished pit edges smashing and ensure the ore reserves growth by 66.9 million tones.

The article is made ready on the results of investigations performed within the framework of the UB RAS inter-disciplinary project No. 12-M-23457-2041 “Earth mineral resources development: the prospects of expansion and all-round mineral raw material base development of the Uralsmining-metallurgical complex”.

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