Measuring and modelling of dry bulk rock density for mineral resource estimation
Measuring and modelling of dry bulk rock density for mineral resource estimation
复制标题
用于矿产资源估算的干散装岩石密度的测量和建模
DOI：
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发表时间：
2013
期刊：
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通讯作者：
M. Abzalov
中科院分区：
文献类型：
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作者：
M. Abzalov
估算矿石吨位以及确定所含金属量需要岩石密度信息；这是因为矿化品位通常以经济上可行的成分、金属或矿物与重量单位（例如克/吨）的比率来报告。尽管岩石密度对于准确估算矿产资源的吨位和品位具有明显的重要性，但该参数经常被忽视，并且比测定的金属品位受到的关注要少得多。具体地，可以选择岩石密度测量的数量和空间分布，而不考虑岩石密度测量对矿物资源估计的影响。本文试图解决与当前岩石密度建模实践相关的几个问题。本文的第一部分概述了最常用于测量岩石干堆积密度 (DBD) 以估算矿产资源的方法。接下来的第二部分提出了岩石密度地质统计建模的方法，该方法被建议作为为密度样本选择最佳采样网格的数学支持方法。它得到了几个矿床案例研究的支持，其中估计并提出了地质统计学最佳 DBD 采样网格，用于定义测量和指示资源以及品位控制目的。有人指出，勘探团队需要确保钻井活动期间收集的 DBD 数据不仅足以定义资源和储量，而且间隔足够紧密，以便进行精确的品位控制。根据地质统计分析，品位控制 DBD 网格的最佳值类似于定义测量资源或（不太常见）所研究矿床的指示资源所需的化学分析网格。
Rock density information is needed for the estimation of ore tonnage, and also for determining the amount of contained metal; this is because mineralisation grades are usually reported as a ratio of the economically viable components, metals or minerals, to weight units (e.g. grams/tonne). Despite the obvious importance of rock density for the accurate estimation of tonnage and grade of mineral resources, this parameter is often overlooked and receives significantly less attention than assayed metal grades. In particular, the quantity and spatial distribution of the rock density measurements may be chosen without considering the impact of the rock density measurements on the mineral resource estimation. This paper attempts to address several issues associated with current practices of rock density modelling. The first part of the paper overviews the methods most commonly used for measuring the dry bulk density (DBD) of rocks for the estimation of mineral resources. This is followed by a second part proposing the methodology of geostatistical modelling of the rock densities which is suggested as a mathematically supported approach for choosing optimal sampling grids for density samples. It is supported by several case studies of the deposits where geostatistically optimal DBD sampling grids were estimated and proposed for definition of the Measured and Indicated resources and for the grade control purpose. It was noted that the exploration team needs to assure that DBD data collected during the drilling campaigns are not only sufficient for definition of resources and reserves but are also closely enough spaced to allow accurate grade control. The optimal for grade control DBD grids, according to the geostatistical analysis, is similar to the chemical assay grids required for definition of the Measured resources or, less commonly, Indicated resources of the studied deposits.