Multiple indicator Kriging estimation method and a case study based on fractal distribution

Geostatistical method, also known as Kriging method, is the mainstream method of resource estimation.When the grade of mineralized elements presents mixed population distribution and no effective estimation domain can be spatially subdivided, the multiple indicator Kriging (MIK) method should be employed.Traditional MIK estimation generally chooses decile as indicator thresholds.However, the geological significance of the thresholds using this method is not clear, the accuracy of estimation may be affected when the sample data within the minimum and maximum thresholds are too few, and the modeling process is tedious.The results show that the grade of mineralized elements has the characteristics of fractal distribution, and the indicator thresholds of MIK can be determined by using the fractal method to decomposing the mineralized mixture population.Taking the resource estimation of a copper and cobalt deposit in DRC as an example, this paper compares the MIK estimation of the fractal distribution method, the probability graph method and the decile method.The results show that the MIK estimation based on the fractal distribution is basically consistent with the decile method.Moreover, the fractal distribution method has simpler modeling process and clearer geological significance compared with the traditional decile method.It has a great value of popularization and application as an improvement of the traditional decile MIK method.