The article considers some specific peculiarities of metasomatically altered rock of Svetloye gold and silver field , which is situated in Okhotsk region of Khabarovsk Territory. Enclosing rock of ore zones of the field under consideration are lava and tuff of andesite and andesite-dacitic, which are altered in all parts in the result of hydrothermal-metasomatic processes. At the field the following types of metasomatosis are displayed: propylitization, secondary silification, and argilization. Each type is characterized by own origination conditions – alkali composition of hydrothermal fluids and the temperature of their origination. The characteristics of physical and mechanical properties of field rock is examined, the regularities in strength characteristics reduction are defined by means of “weakening” minerals presence in rock, the regularities in the alternation of properties depending on the type of metasomatosis and the distribution of minerals in the cut of the field. With the purpose of defining the peculiarities of physical and mechanical properties alternation, the analysis of the results of field rock mineral composition and physical and mechanical properties determination is fulfilled. The regularities stated are important at the solution of the problem of the mineral stripping, the degree, character, and type of mine workings support.
Rock massifs are usually in ultimate stress state, and maximum values of stresses are limited by strength characteristics of rock massifs. Ultimate rock equilibrium is maintained by stresses uploading with the development of brittle deformation within the massifs. Mass fissures of pre-deformation develop in near-surface zone of brittle deformation. The power of this zone in rock massifs reaches 300–500 m. The network of interrelated open fissures of pre-deformation forms harmful complex of near-surface rock jointing close to earth surface. Geomechanical rules of brittle deformation processes development predetermine the forming of vertical fissure zoning. Quantitative rules of vertical fissure zoning development allow determining basic geomechanical characteristics of rock massifs.
The method of estimation of engineer-geological conditions of stopping of Polar Urals deposits is regarded. The main factors determining the conditions of workings of gold ore deposits are stated. The prognosis of changes of engineer-geological conditions and development of engineer-geological processes was made.
The analysis of the problems of developing of ways of minerals deposits generalization on engineering and geological conditions of their development is given. The principles and criteria for determining the complexity of geological conditions of mineral development are considered.
The article deals with problems of natural and human-induced processes in the city of Khanty-Mansiysk. Processes are characterized by diversity and intensity of a wide range of activity and adverse effects; processes of erosion and slope stand out. About 40-50% of the city center, located within Samarovsky outcrop, is in different scale exposed to such processes as gullying, landslides, debris and suffusion. With a significant variety of formation conditions and peculiarities of such processes, the common patterns are the increase of the affected areas and the growing intensity of the process. Under their threat are many residential buildings, industrial sites, structures of the world famous "Biathlon Center". This research made it possible to establish the main features and patterns of development of these processes.
The position of mineral deposits of the Urals of various geological and industrial types in rocks of structural and formational megazones, their belonging to the metallogenic sub-provinces, zones and subzones are considered. Natural and technical system of mineral deposits as a structured interaction region of the rock mass deposits and mining facilities was characterized; modalities of the interaction region and their components: physical and geographical conditions (climate, biota, topography, hydrology); geological and structural conditions (tectonic features, occurrence of rocks); lithological and petrographic conditions (genesis, age, composition and properties of rocks); permafrost-hydrogeological conditions (types of groundwater, frozen state of rocks); geodynamic conditions (stress state, geological and mining-geological processes). Mining facilities (quarry, underground mining) include: type of facility, method of construction, construction of excavation. Deposits are differentiated by the complexity of geotechnical conditions of their development into three groups - simple, medium and difficult. The features of the development of mineral deposits of varying complexity in open pit and underground mining were considered.
During geophysical surveys on a number of objects Balkashinski ore district of the Republic of Kazakhstan the existence of anomalous natural electric fields over uranium deposits in the bedrock was revealed. At the same host rocks do not have a high content of any sulfide minerals or graphite, but are characterized by high fracture. Amplitude of anomalies reaches +250 mV. Repeated measurements showed that over time the amplitude anomalies of electric fields are not constant. All these factors are signs of natural filtration of the identified anomalies. Analysis of foreign publications on the topic indicates that the anomalies were observed in a number of foreign uranium deposits. Thus, the positive anomalies of natural electric fields can be used as an additional search feature in determining promising areas for the detection of uranium fields.
On the example of the number of hydrothermal uranium deposits common results of geophysical methods for prospecting ore-bearing structures in the bedrock are considered. Effectiveness of individual methods was assessed by scale, encompassing the physical properties that are typical for rocks that host uranium mineralization such as porosity, fracturing, presence of groundwater flow, silicification, carbonation and sulphidation. The contrast and depth of the methods were also taken into consideration. The highest weight values obtained for methods based on the measurement of electrical resistance, in second place – obtained using the method of induced polarization, the third – gravity exploration. Magnetometric exploration methods and gamma survey received the lowest scores. This data can be useful in the formation of a rational complex field of geophysical methods for finding uranium deposits.