Abstract
Ukraine is in 10 countries with the largest reserves of iron ores, and the iron ore industry and metallurgical complex are budgetary sectors economically important for the country. For now the mining and metallurgical complex is experiencing not the best of times, and experts say that Ukraine is not using its potential, as it should. One of the main steps in inventory calculation is the determination of boundary value. Boundary value is calculated on the basis of geological, economic, technological and social aspects. Using only geological information, you can calculate the most favorable boundary value using geostatistics.
The main cut-off parameter that determines reserves quality of ferruginous quartzites, which require enrichment by magnetic separation, is iron associated with magnetite Femagn. The paper proposes a tool for choosing the optimal cut-off grade values for evaluating BIF deposits using the example one of the West Azov group deposit. Comparison of cut-off parameters for reserves calculation of iron ores within the Azov Group deposits is carried out.
To find the optimal cut-off grade Femagn using geostatistics and spatial modeling, we analyzed the dynamics of changes in the amount of reserves from changes of cut-off grade Fe. Fluctuations in average Fe grade also were took into account. The paper substantiates the optimal cut-off grade values of Fe associated with magnetite in the range of 12–14 %.
The interval of the largest changes in reserves quantity with an increase is fixed for range of 12–18 %. Beyond this interval there is a minimal fluctuation of ore reserves quantity as a result of cut-off grade’s changes.
In order to find optimal cut-off grade values using geostatistics and spatial modeling, it is necessary to follow the dynamics of reserves’ quantity changes depend on Fe cut-off grade, as well as to take into account average Fe grade fluctuations when changing cut-off grade.