Reserve Evaluation of Esfordi Phosphate Mine using Geostatistical and Artificial Neural Network

Reserve evaluation is one of the most important parameters for mine designing and several methods have been developed in this regards. Among these methods, in addition to geostatistical methods, artificial methods such as Artificial Neural Networks (ANN) are suitable for reserve evaluation. In this research, geometrical and block model of ٍEsfordi phosphate mine are prepared and the reserve is estimated. The block model contains 100 thousand blocks with dimensions of 25×25×5 m. To estimate the grade of each block, both methods of geostatistical and ANN methods are used. For geostatistical estimation, normal kriging is applied. In ANN a perceptron multilayer network is used and for training of network LM method is considered. Based on geostatistical and ANN methods, the amount of estimated reserve is 16. 5 Mt with an average grade of 11. 44% and 17. 5 Mt with an average grade of 11. 83%, respectively, considering a cut-off grade of 6%. The results obtained from these two methods are identical to each other and difference is less than 6%. This estimation is a requisite for improving present design of the mine with an objective of selective mining up to sea level of +1720.