Delimitation of Mineral Deposits

determining the shape and distribution boundaries of mineral deposits and identifying sections with different grades of mineral raw material within the deposits. Delimitation of mineral deposits is a key step in evaluating mineral reserves.

During the early stages of the prospecting and evaluation process, the delimitation of mineral deposits is based on the results of a geological survey, geophysical and geochemical investigations, and exploratory drilling and excavations. The values of maximal and minimal thicknesses of the mineral deposit, quality indexes of the mineral raw material, and geological mining parameters are determined by analogy with values obtained at already analyzed and exploited deposits of the same genetic type found under similar geologic conditions. Subsequently, the results of preliminary and detailed analysis and mining economic calculations are used to establish the temporary and permanent conditions for estimating the deposit’s reserves. Taking into account these conditions, scientists delimit mineral deposits by making additional exploratory excavations at the estimated outer contour of the mineral deposit and at the boundary lines dividing the deposit into areas with reserves of different commercial value or fundamentally different raw material quality and geological mining modes of occurrence. During the actual working of the deposit, the contours of the deposit are determined with greater precision where necessary by preliminary excavations and exploratory shafts.

When the geologic data are processed and estimates of mineral reserves are made, mineral deposits are delimited using maps, diagrams, and geologic sections. A contour of the ultimate extent of a deposit (zero thickness contour, or zero mineral content contour) is sometimes constructed to solve general geologic problems, in particular, to establish the nature of mineralization and an overview of the the mineral’s distribution.