Quality Control of Assays

In recent years there has been a strong international movement toward knowing and improving the quality of information used in the mining industry for resource and reserve estimation. In Canada, this culminated with the implementation of National Instrument 43-101 which incorporates, in part, general requirements pertaining to technical matters involved in obtaining assay data and the recognition that those data are of adequate quality to both publicize and form the basis of a resource or reserve estimation.

This course will demonstrate how the qualified person is able to meet the assay quality requirements of NI 43-101. Topics to be discussed include duplicate data collection, use of standards and blanks, simple statistics in the evaluation of standards, recognition of outliers, binary graphs as an interpretive aid to evaluating duplicate data, and displaying and analyzing data.

Emphasis will be placed on the use of simple statistical approaches that can be used to quantify data quality. Examples will be used to illustrate how sampling error, sub-sampling error, and analytical error can be determined, and how such results can be used as a basis for improving data quality. Reference will be made to several procedures used in the industry to quantify precision and the general pros and cons of these methods.