Exploration of Mineral Deposits
Exploration of Mineral Deposits
the aggregate of operations involved in geological exploration and the tests related to these operations, carried out to identify reserves of mineral resources in the earth’s interior and provide a geological and economic assessment. Data from exploration are used to identify the geological structure of the deposit; the characteristics of spatial arrangement; the conditions of bedding; and the shapes, dimensions, and structure of beds of useful minerals. The data are also used to identify the quantity and quality of minerals, the technological properties of the minerals, and the factors that determine the conditions for subsequent exploitation.
Exploration follows geological surveying and prospecting and includes two preplanning stages: preliminary and detailed. Preliminary exploration clarifies the arrangement of the geological structure of the sector, the overall scale of industrial mineralization, the average quality of minerals in the interior, and the advisability and sequence of industrial development of the deposit. Detailed exploration is done in deposits earmarked for priority development and provides the information necessary for planning the mining enterprise. Unlike the preliminary stage, detailed exploration may concentrate on particular mineral beds and not the entire deposit. When the mining enterprise is in operation, two types of exploration are conducted: operating and continuing exploration. Operating exploration determines the structure, composition, and quality of beds within distinct operational units, such as levels, panels, blocks, or steps. Continuing exploration within the mine area is done to study the geological structure of the deep-seated parts and flanks of the deposit, discover new beds, and estimate mineral reserves in the new beds.
Geological exploration work involves tracing mineralized sectors of the interior and delimiting mineral deposits by selectively intersecting them with exploratory boreholes and mining excavations. The intersections together form an exploratory grid, a system of spatially arranged artificial exposures that are studied and sampled in detail. Stratified and isometric beds of useful minerals are explored by square grids, and elongate beds are studied by rectangular grids. Thin ore veins are often traced by mine excavations along the strike and dip. Bodies of useful minerals that are directly under a cover of loose sediment are explored by ditches and pits. Deep-lying deposits are explored by exploratory boreholes. Underground mining excavations are used to explore complex-structured deposits of solid mineral products when reliable data can only be obtained by direct study of the mineralized sectors of the interior.
Geological, geochemical, geophysical, hydrogeological, and geological engineering investigations are made in mining excavations and boreholes. Core samples and the walls of mining excavations are documented in photographs or drawings, samples of the useful minerals and enclosing rocks are taken, and the composition and structure of the minerals and rocks are described. The primary halos of useful elements and accessory elements around mineral beds are studied. Dip measurements are taken, comprehensive well logging is done, and underground geophysical tests and observations of subterranean-water conditions are carried out. The mining and technical properties of the useful minerals and enclosing rocks are also studied.
Sampling of wells and mining excavations is done to evaluate the average content of useful components and harmful impurities and to determine the technological and technical properties of the useful minerals. This involves systematically selecting samples and analyzing them or evaluating the quality of useful minerals in wells and excavations by geophysical methods. Geological maps and cross sections are drawn up from the results of study and sampling, and mineral reserves are outlined and calculated. Reserves are calculated on the basis of the specifications that govern industrial demand as to the quality of useful minerals and the conditions of delimiting reserves and working and processing the mineral. The greatest errors in calculating reserves are analogy errors, which result when data obtained from exploratory cross sections are applied to interior areas close to them. The magnitude of these errors depends on the complexity of the geological structure of deposits, the variability of the properties of the useful minerals in the interior, and the geometry of the exploratory grid and calculation blocks. When reserves are calculated, the initial data are processed mathematically and with due consideration of the above-mentioned factors.
In the USSR, exploration of mineral deposits became an independent branch of the theory of useful minerals and mining science in the 1920’s and 1930’s. It was developed by I. S. Vasil’ev, V. M. Kreiter, N. V. Baryshev, and P. M. Tatarinov.
REFERENCESPodschet zapasov mestorozhdenii poleznykh iskopaemykh. Moscow, 1960.
Teoreticheskie osnovy i melody poiskov i razvedki skoplenii nefti i gaza. Moscow, 1968.
Kreiter, V. M. Poiski i razvedka mestorozhdenii poleznykh iskopaemykh, 2nd ed. Moscow, 1969.
A. B. KAZHDAN