National Polytechnic University of Armenia, Erevan, Armenia:

A. G. Oganesyan, Head of Chair, Professor, Doctor of Engineering Sciences, hov_armen@mail.ru
A. A. Alaverdyan, Associate Professor, Candidate of Engineering Sciences

Lernametallurgiai Institute, Ereva n, Armenia:

S. S. Karslyan, Senior Researcher

The Sotk gold deposit in Armenia features very difficult geological and geotechnical conditions: it is represented by steeply dipping and thick lodes and mineralized dykes, thin lodes and veins at a considerable depth, which dictates using hybrid open pit/underground mining. Under such conditions, optimi zation and justification of hybrid open pit/underground mining reduces identification of the boundary between open pit and underground mines and validation of optimal underground mine parameters. The boundary between open pit and underground mine areas is determined from the equality of the limiting and perimeter stripping ratios: it is expedient to use open pit mining method down to a depth of 2250 m and underground mining method beyond the limits of the open pit mine. The recommendatio ns for mining beyond the limits of the open pit mine include:
– in case of an ore body or its parts to 3 m thick: top downward mining by slices, with armored concrete floor between slices and with ore haulage by scrapers; in case of an ore body more than 3 m thick: systems of top downward mining by slices with cemented backfill, with self-propelling equipment;
– in case of an ore body or its parts thicker than 8 m, with gold content to 2 g/t: sublevel caving; in case
of gold content of ore more than 2 g/t: systems of top downward mining by slices with cemented backfill.

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