MINERAL RESOURCE ESTIMATION AND MINE PLANNING IN A GOLD-COPPER DEPOSIT: A MULTIVARIATE GEOSTATISTICAL PRACTICE
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Date
2022-03-31
Authors
Kuanyshev, Shingiskhan
Journal Title
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Publisher
Nazarbayev University School of Mining and Geosciences
Abstract
In mining practices, the life of every mine begins with resource estimation and
predicting the possible income from operations. Thus, the first step identifies the potential
implementation of mine into actual operation. Due to these reasons, geostatistics and resource
estimation are crucial part in mining engineering. Moreover, geostatistics offers an
appropriate method for accurately determining several properties of a deposit that are critical
for mine design. However, because of the complexity and high cost of sampling variables in
mines, some challenges could be faced in determining the grades of present minerals. For
instance, the estimation of a variable in a univariate deposit is much simpler than in the case
of a multivariate deposit. In this regard, geostatistics has been evolving throughout the years
to propose some solutions to this issue. For instance, the computation of cokriging instead of
kriging is a good tool in determining the grades with lower error as it takes into consideration
the correlation between two or several variables.
In this study, the case of a real-life Australian multivariate deposit of gold and copper
was taken into discussion. After computing ordinary kriging and receiving a block model, it
was found out that there is a presence of a high correlation between Cu and Au. Thus, after
realization of an idea of ordinary cokriging with keeping all the steps and details, the mine
planning of both methods was done and compared.
Therefore, it was concluded that in resource estimation, ordinary cokriging provided
us with much better results with lower variance, leading to the superior outcomes in mine
planning part including economic aspects. The results of this study showed that by using
cokriging instead of kriging, it is possible to increase the NVP (net present value) of a mine
project by approximately $120.000.000. However, after proceeding the modelling, some
drawbacks of deterministic methods were established. For instance, smoothing effect and
negative values in kriging and cokriging, as well as not taking into consideration the time
value in mine planning step. Thus, the future research should be focused on the side of
stochastic methods.
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