The book is a practical guide to the study of the material composition and testing of enrichment, hydrometallurgical and thermochemical methods of processing gold-containing ores. The book describes the principles of technological typing of ores and taking technological samples. A systematic description of the operation for preparing technological samples of ores for studies of modern physical and chemical methods for studying the material composition of ores and the properties of ore gold, laboratory studies and semi-industrial tests of ores of various types is given. For the first time, the methodology for testing heap leaching, recycling of water and neutralization of effluents, semi-industrial tests of ores, including their self-grinding, is described. The book is designed for engineering workers (concentrators, metallurgists, mineralogists), university students and laboratory assistants studying gold and complex gold-bearing ores in laboratories of factories and institutes.