文章总结了质量保证与质量控制(Quality Assurance/Quality Control,QA/QC)在地质勘查和资源调查评价样品分析中的意义,根据最佳工业实践,推荐质控样品的插入率≥20%.对质控样品的选择与评价方法进行总结,标准样品应与待测样品基体匹配且含量范围涵盖整个待测样品的含量水平,标准样品的测试结果使用控制图进行准确度判断;重复样品应在每一个重要的采样、制样阶段进行采集,并且应随机选取,重复样品的分析结果通过散点图判断精密度是否达到预期设定界限,通过相对偏差图可以获得不同因素对精密度的影响,国际上通用的量化重复样品精密度的方法是计算变异系数(Coefficient of Variation,CV);空白样品的目标元素含量应低于检出限,实验室空白样品一般为高纯度的石英砂,实际的资源勘查项目中也可采集野外空白样品进行污染监控,空白样品的控制限为3～5倍方法检出限;外检样品应送到级别相当或更高的实验室进行检测,判断两个实验室测量结果的差异,外检样品选择应随机,通过散点图判断外检样品结果的可靠性.文章通过国际上资源调查评价中质量控制与质量保证的实例进行总结,与国际标准对标,对于今后海外找矿,海外资源调查评价有重要作用.
Application of Quality Assurance and Quality Control in Sample Analysis of Oversea Geological Exploration and Resource Survey Evaluation
This paper summarized the importance of Quality Assurance and Quality Control(QA/QC)in sample analysis in geological exploration and resource evaluation.On the basis of international best industrial practices,the recommended insertion rate of quality control samples should≥20%.How to choose quality control samples was discussed and the evaluation methods of quality control samples was summarized.Certified reference materials should have the same matrix with the target samples and include the range of whole concentration levels,control chart is used in accuracy evaluation of certified reference materials.Duplicated samples should be collected randomly in each sampling steps,quantile-quantile plot is used to access if the precision is within the expected setting limit.Different factors on the effect of precision can be obtain through relative difference plot.Average Coefficient of Variation(CV)is the most commonly used methods in best industrial practices to evaluate precision of duplicated samples.Blank samples are barren samples with an expected low grade,which should below detection limits.High purity quartz is used in laboratory analysis and field blanks can be used in resource evaluation projects to monitor contamination.In general,control limit of blank samples is 3～5 times detection limit.External check samples should be sent to the laboratory with same level or higher level of the testing to access the accuracy and bias of the two laboratories.The external check samples should be chosen randomly and evaluated by quantile-quantile plot.This paper summarized the examples of quality control and quality assurance in the international resource survey and evaluation,benchmarking with the international standard,which is of great significance in overseas mineral exploration and resource survey evaluation in the future.
geological explorationresource survey evaluationquality assurance and quality controlbest industrial practice
万方数据
维普
