The preparation and analysis of minerals for use as reference material

This report covers the progress made in the collection of the material for reference samples, and the five interlaboratory analytical programmes (ferrochromium slags, fluorspar, 'mixed' NIMROC samples, rare earths, and ferromanganese slags). The description of the internal analytical programme has been subdivided into eight main categories, and a comprehensive list of evaluated results covering a wide range of materials is included. Additional results for thorium, rare earths, tin, tantalum, and niobium for the appropriate reference samples are included in updated tables. The main purpose in the preparation of these samples is to provide control samples for analytical work at the National Institute for Metallurgy. Where there is a special need, limited quantities of the samples can be made available to other laboratories