Polymetal Engineering JSC, Saint-Petersburg, Russia

V. B. Kolpakov, Head of Department, Candidate of Geological and Mineralogical Sciences

Polymetal UK JSC, Saint-Petersburg, Russia

A. V. Krasnoperov, Leading Geomechanical Engineer, KrasnoperovAV@polymetal.ru

South Verkhoyansk Mining Company, Yakutsk, Russia

S. A. Antonyuk, Chief Geomechanic, Candidate of Engineering Sciences

The pursuit of complete extraction of valuable components from raw ore dictates application of underground mining systems with cemented paste backfill. In its turn, mining with backfill requires optimizing backfill compositions at preservation of mining safety. Preparation of backfill is a rather simple process including certain operations, namely:
—delivery of cement from the surface infrastructure site to special sumps arranged in lateral haulage drifts in a mine;
—cement is mixed with water in the sumps using load–haul–dumpers (LHD) employed in backfilling;
—after cement is mixed with water (this product is named cement milk in mines), LHD bring broken rocks delivered from heading drifts by dump trucks and stored not far from the sumps;
—rocks unloaded to a sump is mixed with the cement milk using LHD;
—the prepared backfill is thrown to a mined-out stope from the upper sublevel by LHD. 

Sublevel open stoping with cemented paste backfill at Polymetal JSC has proved to be an effective method of underground mineral mining, which ensures complete extraction of minerals and stability of enclosing rock mass. The foreign and domestic approaches to the standard strength analysis of cemented paste backfill are reviewed. Some variants of the integrated analysis of standard strength of cemented paste backfill per different specifications are proposed, and the methodology is presented for calculating sizes of artificial rib and crown pillars and optimizing backfill compositions for them. The problem is considered in terms of operating mines in the Khabarovsk Krai and Magadan Region.

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