In-situ leaching of molybdenum and uranium is becoming an increasingly common process. The features of the material composition of ores, leading to a decrease in their filtration properties, were considered. Activation leaching with leaching solutions that have undergone electrophotochemical activation before contact with the ore mass were studied. Activation preparation of leaching solutions promotes the synthesis of clustered water molecules with collectivized protons and hydroxyl ions, as well as active forms of oxygen and hydrogen. Cell leaching of molybdenum from mature tailings of the Shakhtaminsk deposit was studied experimentally. After pre-oxidation with an active carbonate solution, a model borehole leaching was carried out with a chloride-hypochlorite solution. Molybdenum extraction on resin a was 85 % in 30 days. Experiments on the percolation leaching of uranium from the ores of the Uchkuduk and Sugraly deposits confirmed the potential possibility of a significant increase in the extraction of uranium by electrophotoactivated percarbonate solutions relative to aqueous solutions of sodium and ammonium carbonate. When leaching with carbonate solutions without an additional oxidizing agent, the extraction of uranium from the Sugraly deposit ore sample was 52 and 59 % (sodium carbonate and ammonium carbonate). The use of hydrogen peroxide as an oxidizing agent made it possible to achieve 87-88 % extraction into pregnant solutions in 21 days without pre-oxidation. The performed studies confirm the processing capability of extracting uranium and molybdenum by percolation leaching in columns and borehole leaching.
Regularities of forming of strained – deformed state in elements of designed variants of systems of development on various mining stages for Nikolaevskoe and Yuzhnoe polymetallic deposits are determined on the results of numerical modeling. Analysis of technogeneous stress field made it possible to discover some potential burst-hazardous sections of the rock massif and to substantiate effective rock pressure decreasing measures for preventing dynamic rock pressure occurrences.
An assessment is given to the present-day state of control of dynamic rock pressure manifestations in the rockburst-hazardous ore mines of the Far-East district. Consideration is given to the used methods and facilities for control of rock pressure and the ways for their improvement . Basic foundations of methodical approaches to the assessment of geomechanical state of rock mass by data of geoacoustic control are considered.
On the example of the South-Argun uranium ore district of Zabaikalie consideration is given to the interaction of regional and local fields of stresses. The district includes a number of deposits prone to rock bursts. The performed analysis contains data on recent geodynamics of the explored part of the Amur geoblock as well as on geomechanical and geologo-structural materials of Tulukuev caldera and of Antey deposit. It is shown that with the use of the M.A. Sadovsky relationship the indices of local structural forms of a row are subjected to unified laws of deformation and fracturing. Conclusion was made that at the beginning of deposit exploitation the direction of action of stress field within rock mass conformed to regional one, and then it considerably changed under influence of large-scale mining operations.
The article considers the conditions and pattern of dynamic rock pressure manifestations in mining the «Antey» deposit of uranium ores. Data on geological, technological and geomechanical conditions of the deposit mining are given. The methods and means for rock pressure control are described as well as the results of their application at deep horizons of ore mine are given.
The article contains the results of numerical modeling of stress-strain state in constructive elements of mining systems, applied at hazardous and prone to rook bursts deposits of the Far-East. Consideration is given to some stated regularities of forming of teсhnogenic stress field and geomechanical processes proceeding in rock mass of minable deposits which allow to substantiate a сomplex of measures for prevention of dynamic rock pressure manifestations.
The paper presents results of conducted research using regional and local methods of forecast and control over geomechanical state of the rock mass at burst-hazardous Nikolayevskoye field, located in a geodynamically active region. The study subject is the ore mass of Nikolayevskoye field, characterized by man-induced and tectonic disturbances and high geodynamic activity. The aim of research was practical implementation of methods and instruments of forecast and control over geomechanical state of the burst-hazardous rock mass and safety improvement of mining operations. Exploitation practice of burst-hazardous fields demonstrates that forecast accuracy of hazardous rock pressure demands cutting-edge multi-level systems, where local methods and tools complement regional ones. A regional forecast of rock-burst hazard at Nikolayevskoye field was performed by means of seismoacoustic method using automated control system for rock pressure (ACSRP) «Prognoz-АDS». Local forecast was carried out using «Prognoz-L» device, geophysical (sample disking) method and visual observations of dynamic pressure manifestations in the mining tunnels. Quality assessment of stress-strain and burst state of the rock mass was performed using specialized software «PRESS 3D URAL». Integration of engineering and geomechanical data in the process of conducting research guarantees a relevant assessment of rock-burst hazard in various areas of the field at various stages of its development. Practical verification of the system, where local methods and tools complement regional ones, demonstrated satisfactory results at Nikolayevskoye mining plant, which makes it recommendable for other mining facilities extracting ore at great depths under similar conditions of active geodynamic processes.