Geochemical and statistical investigations into quality control management of samples in a mine within the Sefwi Bibian gold belt
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Date
2002-11-29
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Abstract
The problem of data analysis is a combination of philosophy of approach, clear understanding of the quality and nature of the data to be investigated. To attempt to carry out blind evaluation of data by submitting the data set to any one of the ever increasing number of packaged software systems and expect the computer to do the thinking is patently wrong. Generally, sample data is usually collected with specific goals. The collection procedure ideally should incorporate an element of rigorous statistical design that provides efficiency in the accumulation of data. Representativeness of the data relative to the source, monitoring during data collection and analysis are vital in providing a reasonable measure of quality.
The research is based on gold assay results from three analytical laboratories referred to as laboratories ‘K’, ‘L’ and ‘M’ in the text. The data sets were subjected to the chi-test, the student’s t-test and linear correlation coefficient to ascertain measure of similarity between the original and duplicate samples from the laboratories.
Laboratories ‘K’ and ‘L’ registered near perfect positive correlation of 0.998 and 0.992, respectively, between original and duplicate samples while laboratory ‘M’ recorded reasonably good positive correlation of 0.723. However, the 27.7% bias registered by laboratory ‘M’ fell out of the 95% confident limit set for the laboratories. All the data sets failed the goodness-fit test. The samples showed a rather positive skew owing to excess of low grade values, a situation attributed to a batch effect. From the statistical deduction made from the geochemical data, It is recommended that samples from anomalously high and low grade zones may not have to be lumped together as one batch to the laboratory.
Description
A thesis submitted to the Department of Geological Engineering, Kwame Nkrumah University of Science and Technology in partial
fulfilment of the requirements for the award of Master of Science, 2002