Justification of geotechnology for nonuniform geomechanical medium of Dzhamgyr gold ore deposit

Abstract

The uncertain discontinuity and concentration of the mineralization at Dzhamgyr deposit govern the errors in the appraisal of the commercial ore reserves and in the choice of the optimal mining system parameters. In particular, the ore occurrence discontinuity is different when determined using the ore content coefficient in exploration blocks (observations along the block perimeter at a step of 3.5 m along the dip and strike) or the operational exploration data at a regular grid 3.5×(4–5) m. The accomplished research substantiates the geotechnology based on the geological medium discreteness. It is shown that the extraction-purpose delineation of ore and no-ore and generation of pillars allows using the mixed-type stoping flow chart in enlarged extraction panels. Feasibility of lumpiness-conditioned grading, screening and sensor-based calibration of gold-andquartz ore makes it possible to increase the minimum stoping thickness to 2.5–3 m at the high ore dilution of 70%. This enables using mechanized stoping in larger extraction panels (160×(120–160 m) in combination with shrinkage stoping and /or overhand stoping slicing of very rich (bonanza) ore. With the proposed geotechnology introduced, it is possible to implement planning of investment and economic development of production at the doubled mining output and annual ore extraction of 60 thousand tons at the reduced cost of stoping.The authors appreciate contribution of the Geotechnical Engineering Department Head E. A. Babkin, Vertex Gold Company, to preparation of this article.