SUBSTANTIATION FOR THE AREAS OF APPLICATION OF THE UNDERGROUND MINING METHOD WITH SUBLEVEL ORE BREAKING

Abstract

In Armenia, the mining of thin steeply dipping gold-polymetallic ore bodies was carried out mainly by a mining system with ore storage, and at present with mining method with sublevel ore breaking. The last one is characterized by a significant proportion of ore reserves in interfloor and interchamber pillars: ore losses range from 20% to 60%.

In order to select an economically feasible (optimal) mining method, depending on the condition of the pillars after extraction of the chamber ore reserves, three options were considered: a method of development by sublevel breaking of ore with the leaving of interfloor and interchamber pillars in the subsoil; extraction of pillars by a sublevel caving method; preliminary replacement of interchamber and interlevel pillars in artificial supports by backfilling the raising and haulage drifts with concrete mix. Methods for developing horizontal layers with hardening backfill are also considered.

Using the indicator "critical" gold content in the ore massif, optimal variants of the mining method with sublevel ore breaking were selected:

- with the actual gold content in the ore massif up to 2.3 g/t, it is economically feasible to use the method of developing sublevel ore breaking with the leaving of interfloor and interchamber pillars in the subsoil, and with high gold content in the ore massif - the method of developing sublevel ore breaking and extracting pillars by using the sublevel caving method,

- with the actual gold content in the ore massif up to 1.3 g/t, it is economically feasible to use the method of developing sublevel ore breaking and the extraction of pillars by the sublevel caving method, and with high gold content in the ore massif - the method of developing sublevel ore breaking with preliminary replacement of interchamber and interlevel pillars in artificial supports by backfilling the raising and haulage drifts with concrete mix followed by filling the worked-out chambers with waste rock.

The feasibility of using a horizontal layer mining method with hardening backfill has been proven.