Variable Components Of The Mine Call Factor From A Surface Mine Perspective Using Anglogold Ashanti Iduapriem Mine As A Case Study


Geomatics in Mining

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Monica Naa Morkor Tetteh, University of the Withwatersrand, South Africa,
Frederick Cawood, University of the Witwatersrand, South Africa,


The theory of the Mine Call Factor (MCF) is well-known but not yet fully understood. The definition implies that if the process of sampling, assaying, tonnage measurements in a mine and plant are perfect and there is no mineral loss at any stage during handling and processing, then the MCF should theoretically be 100 %. A MCF investigation begins with establishing the relationship between actual measurements and reporting against measurement protocols. This paper highlights some surface mine issues using Iduapriem Mine as a case study.

These issues include the complexity of material movement, tonnage determination based on survey measurements and a truck tally sheet system (spot tonnage), plus the mine to mill reconciliation strategy. Basic statistical concepts were used to determine the confidence between the two systems of tonnage measurements. Reconciliation factors expressed as a percentage were statistically analysed for discrepancies of tonnages and grades. The result shows that there is a strong positive linear relationship between (survey tonnage and spot tonnage). There is also more confidence in tonnage measurements compared to gold grade. A checklist for identifying and investigating the variable components of a MCF for surface Mines is then discussed.

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