克里格法在离子吸附型稀土矿勘查储量估算中的应用

我国在离子吸附型稀土矿勘查工作中,一般采用地质块段法估算储量,块段法是将矿体划分为不同厚度的块段投影到水平或垂直方向上,块段的划分、各块段的面积和厚度、品位都会影响储量估算结果。本文以赣南某离子吸附型稀土矿床作为研究对象,基于先期勘探钻孔数据资料,运用三维建模软件创建了该矿床钻孔数据库,建立了矿区内矿体的三维DTM模型;采用克里格法对矿体进行稀土氧化物品位分析,将克里格法的储量计算结果与块段法的储量计算结果作对比分析。结果显示,克里格法计算的矿体体积比块段法增加了11.8%,稀土氧化物储量增加了15%,与实际勘探数据相比较,克里格法的计算结果基本合理,且具有快速、准确、方便的特点。本文利用自主开发的以克里格法为基础的三维数字矿山经济评价系统中价格-边界品位敏感性分析模块,动态设置边界品位,灵活圈定不同价格下经济可采的矿体边界,如当精矿的市场价格从10万元/吨变化为12万元/吨时,通过计算获得了此矿山经济可采矿体的空间扩展范围。基于克里格法的三维估算系统能够帮助矿山选择合理的采矿工程布置,有利于满足矿山动态管理的需要以及保证矿产资源的合理利用。

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.