Cut-off grade determination at Shiraldzhin gold deposit by the analogy method of geotechnical engineering

Abstract

Shiraldzhin deposit is a genetic and commercial analog of actual Dzhamgyr mining project. Exploration and operation in both cases are implemented within the unified engineering and management package. The largest and best explored ore occurrence at Shiraldzhin is Sterzhnevoe ore body traceable to 1200 and 350 m along the strike and dip, respectively. The ore body is 0.2 to 13 m thick (average thickness 2.89 m), has the western dip and occurs at the angle of 30–70°. Down to the Level of +2650 m, the proven reserves are appraised as 1795.7 kt of ore and 5985.5 kg of gold at gold content of 3 g/t. For the preliminary risk assessment of Shiraldzhin gold mining in Kyrgyzstan, the analogy method is used, including geotechnical stability parameters of enclosing rock mass and ore body, and correlation of expenses connected with preparatory works, stone drivage and stoping. The correlation factor is determined from the difference of geotechnical parameters of rock masses and ore bodies at the deposits. Considering the global market price of gold and with regard to the operating costs, the cut-off grade is determined for gold-bearing blocks. It is mentioned that the main investment risk of Dzhamgyr and Shiraldzhin gold projects is conditioned by complex geotechnical conditions of mining at intolerable loss and dilution in case of shrinkage stoping. It is required to undertake a test survey to estimate feasibility of more effective accessing and extraction flow charts, in particular, completely mechanized breast stoping and open pit mining.