Taking Representative Samples in Solids-Handling Processes

Non-representative sampling in solids processes has costly consequences. A better understanding of the mathematical basis for sampling and of acceptable quality levels can help to alleviate potential sampling issues and more closely approximate reality Effective sampling in solids-handling processes is critically important to process success and product quality. Conversely, the negative consequences of non-representative sampling are potentially immense. Despite the importance of sampling, the attention placed on ensuring proper sampling and the resources devoted to it are commonly disproportionately small compared to the efforts directed elsewhere. Further, effort aimed at understanding the mathematical basis associated with minimum mass requirements and standard error is generally lacking. For example, the first chapter of Terry Allen’s classic book “Particle Size Measurement” [1] addresses representative sampling, but is often ignored in pursuit of other more “interesting” chapter topics. Consider that errors caused by non-representative sampling have massive economic impact — one example is quoted at $134 million loss over 10 years in a mining project [2]. There are several adages, quotations and clichés from the…