Using Geostatistical estimation and simulation methods in grade modeling of Iron deposit in Darreh-Ziarat, Kurdistan province

This research aims at grade modeling, reserve classification, and assessing risk in grade-tonnage curves in a case study pertaining to Iron mineralization. The Darreh-Ziarat Fe deposit, located in west of Iran, is selected for this research work. Statistical studies were performed on the results of the analysis of ten boreholes. The ordinary kriging (OK) method is run to design a 3D model of grade by incorporating the drilling results. The indicator kriging (IK) method was used to remove waste blocks from the ore block model. Reserve classification was carried out in two ways. A grade-tonnage curve was displayed for different cut-off grades in accordance with the estimation results. In the second section, all the previous steps were performed by the simulation method. For this purpose, the sequential indicator simulation (SIS) method was utilized to remove waste blocks. A grade estimation block model was also generated using sequential Gaussian simulation (SGS). One hundred iterations of the SGS were run to investigate the uncertainty of the grade estimation, create models of the probability of exceeding the specified cut-off grades, and generate an E-type model. The kriging grade-tonnage curve showed that with respect to the cut-off grade of 20%, the tonnage and the average grade of iron are equal to 2.9 million tons and 40.79%, respectively. Also, the E-type grade-tonnage curve showed that with respect to the cut-off grade of 20%, the tonnage and the average grade of iron are equal to 3.1 million tons and 40.92%, respectively. Finally, Iron mineralization targets were recognized by comparing the kriging and the E-type methods.