罗北凹地卤水钾矿开采消耗资源量计算方法对比研究:传统地质块段法和圈定法

Comparative study on calculation methods of resource consumption of brine potassium mine in Luobei depression: traditional geological block method and delineation method

罗布泊盐湖是世界上最大的第四纪干盐湖之一,具有罕见的巨量钙芒硝,并形成了大型液体钾盐矿。罗北凹地钾盐矿已投入开采十余年,查清其矿产资源消耗现状,核实其资源储量现状对指导今后生产及采矿设计具有重要意义。一直以来,卤水钾盐资源储量采用块段法进行人工计算,过程繁琐且效率低,块段法对储卤构造的空间形态描述简单,对地质参数的不均一性刻画不足,且在块段划分上受人为因素影响较大,从而导致不可避免的偏差。本文提出使用GMS软件基于地质统计学的圈定法进行计算,该方法通过建立三维矿体模型,利用克里格块段估值进行储量的计算及汇总,相较于地质块段法能够更好地“圈区”和“算量”,从统计意义上来说,是从变量相关性和变异性出发,在有限区域内对区域化变量的取值进行无偏差、最优的一种方法,可有效消除以上问题的困扰。对比两种方法的计算结果可知:地质块段法和圈定法计算的潜卤水消耗量分别为1.11×10^(9) m^(3)和1.21×10^(9) m^(3),二者的相对误差为8.26%;承压卤水消耗量分别为0.29×10^(9) m^(3)和0.98×10^(9) m^(3),二者差距较大,相对误差达70.82%。分析原因可知,基于地质统计学的圈定法能够更精准且便捷地计算体积,地质参数通过地层网格剖分插值分配到每个节点上,很好地描述了地层的非均质性,计算过程效率高速度快,核实的资源量更精确。本方法同样可应用于其他液体矿产资源储量估算,具有很好的适用性。

Lop Nur salt lake is one of the largest Quaternary dry salt lakes in the world, with a rare amount of glauberite, and formed a large liquid salt lake potash deposit.The salt lake potash deposit in Luobei depression has been mined for more than ten years.It is of great significance to check the consumption of mineral resources and verify the reserves of resources to guide future production and mining design.For a long time, the block method is used for manual calculation of brine potash resource reserves, which is cumbersome and inefficient.The block method is simple to describe the spatial form of the brine storage structure, insufficiently described the heterogeneity of geological parameters, and human factors have a great influence, leading to inevitable deviations.This paper proposes to use the geostatistics delineation method based on GMS software to calculate.This method establishes a 3 D ore body model and uses Kriging block estimates to calculate and summarize reserves.Compared with the geological block method, this method can be better in “rounding area” and “calculating reserves”.Statistically speaking, it is a method for unbiased and optimal estimation of the value of regionalized variables in a limited area based on the correlation and variability of variables, which can greatly eliminate the trouble of the above problems.Comparing the calculation results of the two methods, it can be seen that the consumption of potential brine calculated by geological block method and delineation method is 1.11×10^(9) m^(3) and 1.21×10^(9) m^(3) respectively, the relative error is 8.26%.The consumption of confined brine is 0.29×10^(9) m^(3) and 0.98×10^(9) m^(3) respectively, the difference between them is large, and the relative error is 70.82%.It can be seen from the analysis of reasons that the delineation method based on geostatistics can calculate the volume more accurately and conveniently.The geological parameters are distributed to each node through the stratum grid division interpolation, which well describes the heterogeneity of the stratum.The calculation process is efficient and fast, and the verified resource amount is more accurate.This method can also be applied to the estimation of other liquid mineral resources and reserves, and has good applicability.