Federal State Budgetary Institution "Central Research Institute of Geological Prospecting for Base and Precious Metals" (FSBI "TSNIGRI"), Moscow

Forecasting and prospecting models of mineral deposits are traditionally compiled in tabular form accompanied with a graphic representation. The table considers the factors (criteria) of ore control (structural, lithological, metamorphic, etc.) and prospecting guides (geochemical, panned heavy-mineral concentrate mineralogical, geophysical, etc.) as attributive elements. Such tables usually “summarize” all the ore control factors, regardless of the duration of gold accumulation and the stage-by-stage nature of ore formation. This often leads to “mixing” of elements of different ages (including mutually exclusive ones), which hampers understanding the regularities of gold mineralization and complicates justification of an effective forecasting and prospecting complex. Therefore, the compilation of forecasting and prospecting models of polychronous and polygenic gold ore deposits should take into account characte-ristic features of each stage of the ore formation and should identify ore control factors for each of them.

Key words: forecasting and prospecting models, forecasting and prospecting complexes, ore control factors, polygenic and polychronous lode gold deposits.

Kazakhmys Barlau LLP, Astana, Republic of Kazakhstan

The article presents results of a study of the most copper- and silver-rich chalcocite mineralization, performed during geological and mineralogical mapping of the Zhezkazgan deposit. Results of constructing a 3D mineralogical model of the Zhezkazgan deposit are presented. Regularities in the development of the chalcocite mineralization, its mineralogical and genetic features have been identified and studied. The crucial importance have been determined of the chalcocite mineralization in the formation of the unique Zhezkazgan deposit and its exploitation.

Key words:Chalcocite, mineralization, 3D modeling, genesis, Zhezkazgan deposit, quality of ores, copper, silver.

Federal State Budgetary Institution "Central Research Institute of Geological Prospecting for Base and Precious Metals" (FSBI "TSNIGRI"), Moscow

The effect has been appreciated of the geotectonic settings of formation of volcano-plutonic belts on the ore-formation zonality of their related complex porphyry copper ore-magmatic systems (equivalent to ore regions and clusters). It is shown that combinations of different types of ore deposits, spatially and genetically associated with porphyry copper deposits within the volume of the unified systems, depend on the earth’s crust structure, on the position and nature of the ore-bearing magmatic chambers, as well as on the metallogeny of the belt basements. The identified specific characteristics of the complex multiformational metallogeny of the ore-magmatic systems should be taken into account in the forecast and prospecting for both porphyry copper deposits and their associated ore deposits of other ore-formation types.

Key words: volcano-plutonic belts, porphyry copper deposits, metallogeny, ore-magmatic systems, ore-formation types, ore regions and clusters, forecast, prospecting.

Federal State Budgetary Institution of Science North-Eastern Complex Research Institute named after N. A. Shilo of the Far Eastern Branch of the Russian Academy of Sciences (FSBI SVKNII FEB RAS), Magadan

Mo-Cu and Au-Ag-Pb-Zn ore occurrences of the Verkhne-Myaundzhinsky ore cluster were studied, that located among Jurassic terrigenous complexes of the Inyali-Debin turbidite terrane of the Yana-Kolyma orogenic belt. The Speshnoye Mo-Cu ore occurrence is represented by a sulfide-quartz stockwork and is hosted by porphyry-like quartz syenites with an U-Pb age of 84 Ma; the Spyashchee Au-Ag-Pb-Zn ore occurrence represents a series of carbonate-quartz veins and mineralized zones in Jurassic sedimentary rocks. The geochemical spectrum of the stockwork mineralization is Mo-Au-Ag-Co-Cu-(As, W), while that of the vein-veinlet one is Pb-Ag-Sb-Au-As-Zn-Bi. The Verkhne-Myaundzhinsky ore cluster of the Central segment of the Yana-Kolyma orogenic belt represents a porphyry-epithermal ore-magmatic system formed by a hypabyssal stock of syenite-monzonite composition, by a sulfide-quartz stockwork with Mo-Cu mineralization, and by subepithermal vein-veinlet Au-Ag-Pb-Zn mineralization. Its age corresponds to the age of the second stage of formation of the Okhotsk-Chukotka volcano-plutonic belt

Key words: porphyry-epithermal system, syenite, stockwork, vein, U-Pb age.

Federal State Budgetary Institution of Science Institute of the Earth’s Crust of the Siberian Branch of the Russian Academy of Sciences (IZK SB RAS), Irkutsk

Lithochemical prospecting by secondary scattering halos is considered in practice as attempts to locate ore body outcrops or to significantly reduce the search area. Even when all commonly accepted methodological principles are followed, the researchers rarely show interest in the identified anomalies, for which the vast majority of forecast resources are calculated. The problem lies in the fact that the calculated resources are usually not confirmed, and many anomalies are recognized as false or related to elevated Clarkes of the elements in the rocks. At the phase preceding the exploration drilling and mining workings, the main task is to determine the prospectivity of a certain anomaly. A methodological approach allowing one to justify the prospectivity of identified anomalies was developed using the Soldat massif as an example. Its essence consists in clarifying the contact interaction between the rocks of the massif and the host rocks by analyzing their covering hypergene analogues. Using factor analysis, based on the division of the main rock-forming elements, the spatial position is determined of the main rock types that make up the geological structure of the area. Within a zone of overlapping factors of the rock-forming elements, anomalies of Au, As, Cu, W, Co, Ni, and other elements are established. The localization of these anomalies within the contour of superposition of the rock-forming factors is considered a potential reflection of specific features of the contact interaction between rocks of different types and compositions. The main goal of the article is to attract the attention of researchers to similar situations so as not to miss weak anomalies. For example, positive significant correlations of ore elements are established in samples taken from the zone of overlapping rock-forming factors, while no correlations are observed in samples taken outside this zone. This indicates a unique geochemical environment that needs to be considered and used to predict potential mineralization. All subsequent constructions are related to geometrizing a detailed area in accordance with the identified zone where the main associations of chemical elements were established and the zonal structure of the secondary geochemical field of the massif was studied.

Key words: lithochemical prospecting by secondary scattering halos, zone of overlapping rock-forming factors, statistical processing, correlation.

Federal State Budgetary Institution “Central Research Institute of Geological Prospecting for Base and Precious Metals” (FSBI “TSNIGRI”), Moscow

The article is dedicated to V. A. Novikov, one of the founders of the mineralogical and geochemical studying of “schlichs” (panned heavy-mineral concentrates, HMC) in the former Soviet Union, the organizer and long-term leader of the HMC mineralogical laboratory at the NIGRIZoloto-TsNIGRI. In the 21st century, the Insti-tute continues to use materials collected thanks to his dedicated work.

Key words: NIGRIZoloto, TsNIGRI, heavy-mineral concentrate (HMC) panning method of geological exploration, mineralogical analysis, placer deposits, weathering crust deposits.