The purpose of the article is to date the ore formation process, study the composition and provide the description of mineral parageneses in rocks and ores of the Buluktai Mo-W deposit as well as to estimate the sources of matter and fluids. The Re-Os method (The Center for isotopic studies of A.P. Karpinsky Russian Geological Research Institute (VSEGEI)) is used for dating the molybdenum mineralization. The isotopic compositions of oxygen in silicates and carbon in carbonates is determined in the Geological Institute SB RAS. The isotopic composition of hydrogen of muscovite hydroxyl water is determined in the Center for isotopic studies of the Far Eastern Branch RAS. The isotopic analysis of sulfide sulfur is carried out in the Center for isotopic studies of the Far Eastern Branch RAS and partly at the Tbilisi State University. The age of the molybdenite phase (144±10 Ma) has been determined using the Re-Os method. The isotopic compositions of sulfide sulfur in both molybdenum and tungsten stages show a range of values close to the values of a mantle source. The isotopic compositions of oxygen in the minerals of Mo and W-stages are clearly divided into two groups. The deposit was formed with the participation of a mantle source. Its final stage is characterized with the increased influence of meteoric water as a part of fluids.

The Bakchar iron ore deposit located in the Tomsk region is a part of the West-Siberian iron ore field, which is considered one of the largest in the world. The length of the ore-bearing strip from the south to the north is about 2,000 km, the strip width is about 150 km. At present, the most detailed research was given to the part of the Bakchar province adjoining Polynyanka village. The explorations were performed as a part of the state geological survey. A relatively deep underlying of ore bodies and a high watering degree of the entire geological section were found out. However, this did not decrease the interest in the development of iron ore since its huge reserves form the powerful resource for the development of the region in the future. Hydrogeological conditions of the deposit in many senses determine the most rational methods of its development and ore mining profitability. The purpose of the article is to estimate the forecasted water inflows and their changes over time under open-cast mining of the iron ore deposit. It is required for the preliminary determination of the scope of works for water lowering and designing of their organization scheme including the selection of drainage water receivers. The paper also analyzes the features of the geological structure down to the depth of ore body bedding. The hydrogeological profile of the section has been schematized for the purpose of predictive analytical hydrodynamic calculation of water inflows. The preliminary estimation of water inflows for the future has been obtained under open-cast mining of the deposit with regard to the change of the groundwater drainage intensity over time. The results of predictive calculations show the significant degree of iron ore deposit watering. The authors emphasize the need for further study of hydrogeological conditions, search and justification of alternative methods of ore field development including hydraulic borehole mining.

The purpose of this study is determination of the composition of ore-forming solutions and physico-chemical formation conditions of molybdenum mineralization in the Pervomaiskoe stockwork deposit within the Dzhida ore field (South-Western Transbaikalia). A set of mineralogical, petrographic and geochemical studies allowed to identify the material composition of ore quartz-molybdenum veins and near-veinlet zones. The methods of cryometry and thermometry, as well as modern instrumental microprobe methods of matter study (Raman- spectroscopy and LA-ICP-MS) were used to examine fluid inclusions in quartz of bonanza and lean quartz-molybdenite veinlets. The composition of a gas phase and metal concentrations in the solutions forming quartz-molybdenite veinlets were determined. Conducted studies show that the quartz-molybdenite veins of the Pervomaiskoe deposit were formed in the temperature range of 314-186 °C under the participation of homogeneous fluids with solution heterogenization periods. Total salt concentrations are 6.3-11.7 wt.% eq. NaCl. The gas phase contains CO₂, СH4 and N₂. Using LA-ICP-MS method the concentrations of a wide range of elements including Li, Be, B, F, Na, Mg, Al, Cl, K, Ca, Mn, Fe, Cu, Zn, Nb, Mo, Ag, Sn, La, Ce, Ta, W, Au, Pb, Th, U were determined. The content of the main ore element Mo in bonanza quartz-molybdenite veinlets reaches up to 559 g/t, whereas the average value is 182 g/t. The content of Mo in lean veinlets does not exceed 85 g/t, whereas the average value is 13 g/t. Richer veinlets were formed by near-neutral solutions with a high content of Mo, S and F, while relatively poor veinlets were precipitated from high alkaline solutions. All these enable us to consider the pH of solutions as one of the factors of ore content.

The traditional formation and geotectonic method of forecasting is ineffective when carrying out prospect evaluation survey and exploration development works as these works are carried out on small-sized objects located within the same geotectonic region on the development area of one formation. Under these conditions, it is necessary to attract indirect prospecting factors that reflect the probabilistic nature of the relationship between the mineragenesis processes and geological complexes of various types. This is especially true for nephrite deposits, which generally belong to small and ultra-small objects with a very limited amount of reserves. This paper presents the experience of local multifactorial forecasting of the Golyubinsko-Ollaminskoe nephrite field. The low efficiency of traditional forecasting methods using mineragenic factors of the first kind is shown. It is proposed to carry out local forecasting of nephrite using the mineragenic factors of the second kind and indirect prospecting factors, which are not reflected on the source maps but are informative on the probability of the presence or absence of nephrite deposits. Their potential nephrite content is evaluated using the methods of mathematical statistics. Mineragenic zoning of the area is performed by compiling a multifactor forecast map with the specification of areas with varying degrees of prospects. The following phasing of local forecasting is implemented: the geological structure of the area is analyzed and nephrite-controlling structural and material complexes are classified as mineragenic factors of the second kind; indirect search features are identified; assessment is given to the informative content of various controlling factors and total informativeness of the sections of the combination of features of each category of factors. Single-factor forecast maps and a multi-factor forecast search map of the Golyubinsko-Ollominskoe field nephrite content is compiled. The proposed forecasting methods even on a limited amount of initial geological data allows area zoning according to the degree of prospects and identification of sites for nephrite search.

The purpose of this article is to study the possibilities of mathematical statistics methods under the quantitative interpretation of gravity anomalies. The study uses dispersion and regression methods of mathematical analysis for gravitation field transformation and inversion on example of the Bogdoulin granitoid massif (Mongolia) with the abnormally high content of rare and non-ferrous metals (Sn, Zn, W). As a result, quantitative characteristics of the massif thickness have been obtained as well as the data on the morphological features of its shape. The maximum thickness of granitoids is 12 km. The obtained estimates are confirmed by the results of solving the inverse problem of gravimetry by the method of model selection. Therefore, the application of methods of mathematical statistics for determining intrusive body morphology allows to obtain petrophysical models of geological objects coinciding with the results of quantitative interpretation performed with the use of the program of semi-automatic 3D-Markquardt-inversion of the gravitational field.

The research is aimed at the identification of the structural and tectonic features of the Zeya-Bureya depression by a set of geophysical methods of electrical prospecting and seismic measurements under mineral deposit exploration. The differential sections of resistance were built at the stage of quality analysis of the electroprospecting data using the method of "conducting plane". The data of electrical prospecting and seismic measurements were integrated. The results of integrated interpretation of seismic measurements and electrical prospecting data under the search for hydrocarbons on the territory of the Amur region (Zeya-Bureya basin) allowed to discover volcanic edifices, which could have a significant effect both on the catagenesis of organic matter of sedimentary rocks and the preservation of hydrocarbon traps. Therefore, the integration of geophysical methods at the stage of qualitative analysis allows reliable mapping of the tectonic structures of different order.

A considerable amount of small-scale ore deposits of precious metals has been explored in the Far East. Many of them are characterized by advantageous small depth of ore bodies and relatively high content of metal in the ore. Therefore, the purpose of the article is creation of an excavation complex for the development of steeply dipping ore bodies of moderate thickness. The article analyzes the well-known technical devices and mineral excavation methods that decrease the volumes of overburden operations under the development of deposits. Modern mining machines are equipped with milling tools allow to carry out the excavation of solid rocks without their prior weakening or loosening by drilling and blasting. The author proposes a technology for developing steeply dipping ore bodies of moderate thickness using an excavation complex and crawler dumps to perform mining in remote areas where the construction of roads and delivery of various mining equipment for mining by traditional technologies are often not economically feasible. The excavation complex is mounted on a crawler chassis and is equipped with dozer equipment, a telescopic boom with a milling working body and a bucket loading equipment for lifting the milled rock mass from the mine face to the daylight surface. The movement of the milling working body in the bottom is carried out by means of a telescopic tip that is pivotally attached to the telescopic boom sliding section. The mining technology of small-scale steeply dipping ore bodies with the use of the proposed excavation complex allows to reduce the number of mining equipment and production overburden removal.

Vein deposits of gold in Eastern Siberia are located in remote areas with a severe sharp-continental climate and are characterized by complex conditions of geological environment. This fact jeopardises the profitability of production. The task of increasing the efficiency of ore underground mining in the development of these deposits is relevant. The purpose of the conducted researches is to solve the problems of improving the development efficiency of vein gold deposits. Research methods are based on the profound study of gold ore body occurrence conditions and the geomechanical state of the rock massif using field observations and measurements, mathematical modeling, laboratory and industrial tests. As a result of this, the mining order of inclined gold-bearing veins in technologically separated contours of reserves with the division into production zones (working, stoping, localization) and subsequent backfilling of voids by controlled caving was substantiated and proposed. When this technology was introduced in Russian gold mines, an explosion-proof hydraulic support and vacuum stoping of ore were used for the first time. A structure of the flexible system of stope drift location has been created for a sublevel development system in order to provide the effective excavation of steeply dipping veins. The rock massif was supported from stope drifts. The rocks were supported using rope anchors. This enabled the effective extraction of ore in unstable rocks. It is proposed to mine the balance reserves of thin steeply dipping veins by sublevel ore breaking with combined overhand-underhand stoping and support work. The carried out works directed at the improvement of the development technology of vein deposits allowed significant reduction in the costs of metal production at the mines.

The purpose of the study is to develop a technology and technical means for the elimination of drilling mud losses of various intensity in faulted and cavernous rocks in the sinking zones of a drilling tool and open fractures while ensuring complete and efficient cut-off of water horizon intervals as well as borehole wall consolidation against weakening. The study uses the methods of the analysis of mining and geological conditions of oil and gas well drilling on the territory of Nepa-Botuoba anteclise featuring the drilling mud absorption of various intensity and drops of reservoir and bottomhole pressures, as well as a comparative estimation of the insulation quality of drilling mud loss zones, of time and material consumption for their elimination, prevention of ramble, caving, drilling tool sticking resulting from its jamming by the fragments of fractured rocks. As a result the technologies used at the SredneBotuoba gas-condensate field when performing plugging operations have been studied. The efficiency of various methods and techniques, in the presence of intervals of fractured and unstable rocks in the wells has been estimated. Their advantages and disadvantages have been analyzed. On the basis of all these, the authors have developed an alternative method to control drilling mud losses of any intensity under the excessive pressure on the zone of fractured rocks. The method involves influencing the absorption channels by the polymers that solidify upon the contact with the formation water and significant increase in the volume of the mineralized mixture. This allows the mixture to penetrate into the absorption channels due to the polymer volume expansion and increase of borehole wall stability. Hydroactive polyurethane foam is proposed as a polymer. An immersion pod has been developed that allows the polymer to be delivered directly to the absorption zone. The developed method of delivering the grouting mixture directly to the absorption zone and the use of expandable polymers made it possible to increase the cyclic drilling rate, reduce the consumption of grouting materials, improve the culture and environmental friendliness of production during insulation works as well as shorten the time of well construction.

The purpose of the work is to consider the tectonic and metallogenic features of the Sharyzhalgay uplift of the Siberian platform foundation using the method of the tectonic-metallogenic analysis. The area of the Sharyzhalgay uplift divided into four major blocks - terranes - is characterized by widely distributed linear and circular tectonic structures of different hierarchy. These are the zones of preexistent deep faults, granite and gneiss arches and domes that have metamorphic or igneous nature. Metallogenic zoning is determined by the types of different-rank tectonic elements and is expressed in the combination of linear (metallogenic, ore zones) and nonlinear areal units - ring, ellipsoidal (ore regions, clusters, fields). Manifestation of different tectonic elements of ore control is shown on example of the Okinsky mega anticlinal fold. Late and post-collision stage of orogenesis was productive for endogenous gold, rare-metal and rare-earth mineralization. It is associated with the development of the Central Asian superplume. In the deep structure of the earth's crust the structure of the inversion mafic layer including uplifts and deflections corresponds to the tectonic elements outcropping on the surface and indicates the presence of the areas of increased endogenous activity of the tectonosphere, i.e. suggests the redistribution and concentration of metallogenic elements.