Application of the Kriging Method in Reserves Estimation of the Ion-Adsorption Type Rare Earth Ore

The geological block method is generally applied to estimate reserves for ion-adsorption type rare earth ore in China. In the geological block method, the division of segments, each block segment′s area, thickness and grade greatly affect the reserves estimate. Ion-adsorption type REEs deposits in Gannan were studied as a research objective and are reported in this paper. Based on preliminary exploration drilling data, a database of the deposit drilling and a three-dimensional DTM model were created by using three-dimensional modeling software. The ore grade of rare earth oxides were calculated by using the Kriging method and the mine reserves estimate obtained by the Kriging method was compared with block-method results. The results indicate that volume was increased 11.8% and reserves was increased 15% by using the Kriging method. Compared with the actual exploration data, this result obtained by the Kriging method is more reasonable with the advantages of rapidity, accuracy and convenience. This three-dimensional kriging estimation system can dynamically set cut-off grade. According to the prevailing price and cut-off grade models, the boundaries of REEs ore bodies are able to be delineated with current ore price. The delineation of ore block, grade distribution, weight, ore, metal volume, etc., are essential for choosing the right mining engineering layout and ensure the rational utilization of mineral resources. The 3D visualization of expanded economically recoverable ore bodies showed when the price of concentrate REEs increase from RMB 100000 to RMB 120000. This method and software can help choose a reasonable arrangement for mining engineering, meet the needs of the dynamic management of the mine and to ensure rational exploitation of mineral resources.