The increase in demand for gold in the world over the past
three decades has witnessed an increase in the gold price to accommodate more
efforts of mining and exploration in the gold mining industry. Categorization
of gold mines based on rom-tonnage and grade would be more useful if it can
statistically be used to predict the cost of gold mining. This paper focuses on
establishing logistic and ANN models of the cost effect of run-of-mine tonnage
and grade in the justification of the categorization of gold mines. Gold mines
could be categorized based on the abilities of rom-grade and rom-tonnage to
predict cost. The data used in the generation of the logistic and ANN models
were cash-cost as the dependent variable vs. rom-grade, and rom-tonnage as
independent variables together with the type of mine. The data were obtained
from 160 gold mines selected from the top 20 gold-rich countries in the period
of 7 years from 2002 to 2008. The first analysis was the Logistic Regression
Analysis which was carried out in the SPSS software to determine the
probability of occurrence of low cost given rom-grade and rom-tonnage for
either an open pit, underground, or both mines together. The second analysis
was based on ANN which was carried out to develop the ANN model. Using a
Multilayer perceptron neural network and backpropagation, the ANN Model was
trained to predict the cost. The main results for both logistic and ANN Models
indicated that only rom-grade with a cut-off value of 5.385 g/t can be used to
categorize gold mines as low and high grade while there was not enough evidence
to categorize gold mines based on their rom-tonnage. The only evidence provided
by ANN indicated that the normalized importance of rom-grade was 100% while for
rom tonnage was 48.65. The full models established in this study have a
percentage correct of 62.9 for logistic and 64 for ANN compared to 57.9 by
guess. The relationship between cost vs. rom-grade and rom-tonnage indicated
that only 6.9 percent of the cost is accounted for by rom-grade and
rom-tonnage. This is a weak relation indicating that rom-grade and rom-tonnage
are not the only determinants and therefore on their own must be used with
precaution. Validation of the model agrees well with the actual results. Future
research should focus on the other determinants which account for the remaining
unaccounted 37.6%.
Author(s) Details
Karim Rajabu Baruti
School of Mines and Geosciences, University of Dar es
Salaam, Tanzania.
Please see the book here:- https://doi.org/10.9734/bpi/caert/v5/5929E
