Application of full indicator kriging and inverse distance methods to resource estimation of the Hirred III gold deposit

Document Type: Original paper (Research paper)


1 Amir Kabir University of Technology, Department of Mining and Metallurgical Engineering, Tehran, Iran

2 AmirKabir University, Department of mining, Tehran, Iran


The Hirred III gold deposit is located in Southern Khorasan Province. In this deposit, 32 diamond drilling boreholes and 64 exploratory trenches were implemented. The main purpose of this study is to estimate the resource value of the Hirred III gold deposit using the full indicator kriging method for the first time. The indicator kriging method has been successfully applied to a number of vein gold deposits. Since gold grades have abnormal distributions with a high skewness, and in some cases, the raw grades do not provide proper variograms, that full indicator kriging has been recommended as the appropriate resource estimation method of such deposits. Therefore, in this study, we have implemented this method and compared it with the inverse distance method. The results show that the estimated resources through these methods have a big difference. The block model is the same for each method, which means that the estimation space for both methods is identical. Also, the tonnage and grade values of estimated resource are different for the two methods. The variogram and resource estimation using the indicator kriging method and comparing the results with the inverse distance method show that in the Hirred III gold deposit, the exploratory boreholes are limited and the exploration project needs additional drillings. Finally, when the range of variogram is more than the drilling spacing, the results of inverse distance method can be proposed as the inferred mineral resource.