Investigation and analysis of mining methods from the perspective of the ultimate limit determination requirement

Determining the ultimate limit (UL) of a mine is one of the first steps in mine design, which plays a key role in determining the net present value and profitability of the project. For the open pit mining method, the importance of determining the ultimate pit limit (UPL) when designing a mine is obvious. However, in the case of reserves that, due to their geological or geotechnical conditions, mining is done by a method other than open pit, the necessity of UL determination is not clear for engineers. Therefore, in this study, both surface and underground mining methods- except the open pit method - were investigated to determine the need for UL design for each method by determining the factors affecting the variability of the mining method. The results showed that among the surface methods, dredge mining, borehole mining, and in-situ leaching have the ability to determine the UL, while in quarry mining, open cast (strip) mining, auger mining, and hydraulic method, it is not applicable to determine the UL. Among the underground mining methods, the results showed that it is possible to determine the UL in the stope and pillar, sublevel stoping, cut and fill, stull stoping, square-set stoping, sublevel caving, and block caving due to the presence of grade variability (mineral quality). While for room and pillar mining, shrinkage stoping, and long-wall mining methods, it seems that determining the UL is not applicable due to the immutability of the method.