The book reflects a departure from the previous one in scope and in format. This edition, containing some 28,500 terms, is not meant to be exhaustive in its coverage. It focuses on mining-related terms and excludes such related categories as ceramics, glass, metallurgy, petroleum, and other specialized disciplines. Geological terms which relate to mining are included, as are minerals which have a commercial value or which are associated with such minerals. Many chemicals and materials that are not usually connected with mining or minerals processing do not appear, nor do the chemical elements unless they are classified as minerals.