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The principles and findings of the research of the modern stress-strain state in the top layer of the crust within the Amur lithospheric plate. The integrated geomechanical assessment of ground conditions uses the method of the remote sensing. The authors demonstrate information content of the offered approach to different scale data analysis aimed at either assessment of regional stress state, or at refinement of non-tectonic features in the zones of localization of rockburst-hazardous mineral.

Retaining walls are often built in unsaturated soil at shallow depth above groundwater level. It is critical to define active pressure of the unsaturated soil for designing retaining walls, based on the expanded theory of lateral pressure by Rankin, considering interaction between active pressure and absorption of soil. For unsaturated floury soil occurring above groundwater level for a long time, the angle of internal friction is estimated based on the moisture content-absorption curve, for various depths of retaining walls and different values of absorption, which is constant and decreases with depth, the active pressures and critical height are determined for foundation pits with vertical unsupported walls. The results confirm that absorption reduces active pressure on a retaining wall and the critical height of the vertical walls of the foundation pits can be increased when absorption grows.

The developed pattern of calculation for the parameters of drilling and blasting in boreholes and shot holes is based on a charge design with reduced amount of explosive at the top. The calculation takes into account the action time of the explosion-generated pulse conditioned by outflow of detonation product gases. The authors have derived relations for such rational parameters of drilling and blasting that minimize costs for drilling at the same quality of rock fragmentation.

The authors analyze stresses and strains in elements of undercarriage steel constructions of heavy haulers and state the law of mathematical expectation of stress amplitude. The polynomial relation is set between specific energy input and mathematical expectation of stress amplitude. The maximum permissible operation conditions are found for heavy haulers based on criteria of energy intensity of blasted rock transportation and endurance of steel constructions of rear axle.

The article describes mathematical model of positive-displacement hydropercussion system of single-sided back action. The principal dynamic similarity criteria found are: the reduced ratio between areas of back-stroke chamber and gas chamber; the value proportional to the ratio between potential energy of accumulator and kinetic energy of hammer; the dimensionless lengths of back stroke and gas strut. Based on numerical calculations performed within a wide range of input parameters (similarity criteria), the author has plotted nomograms of isolines of the integral input characteristics and oscillograms of dynamic characteristics, which enables revealing basic mechanisms of behavior of the discussed system in the single-blow limit cycles. In the domain of practical significance parameters, the analytically estimated dimensionless pre-blow velocity should not be higher than 810 units.

The authors propose a calculation procedure for electromagnetic processes running in converters with clamp diodes based on the numerical simulation and method of switching functions. The procedure is specific for the capacity to calculate basic indices of energy efficiency of semiconductor converters in various work modes. Moreover, the procedure is universal in terms of number of voltage levels and number of phases. Owing to modern computation techniques, the time and labor inputs in calculation is greatly reduced. The proposed procedure has been experimentally tested.

The authors discuss experimental physical simulation of operation of loading aggregates with loading stars. The main influencing factors and their ranges are determined, and the obtained results are interpreted. The authors give basic relations characterizing output and capacity of a loading aggregate with lading stars.

It is suggested to enhance output of marketable dimensional stone in quarries with complex inclined and flat-lying fracture networks by minimizing in-process loss as well as by optimizing cutting bench height in order to benefit from higher production rate and lower cutting cost. The procedure has been developed for calculating rational parameters of a combination method of high-strength dimensional stone preparation for cutting at the deposits with complicated ground conditions based on the high-bench two-stage scheme when the first stage is wire sawing of solid blocks and the second stage is cutting of solid block into marketable size blocks using dimensional stone drilling rigs.

The article describes evaluation of natural draft (thermal drop of ventilation pressure) and determination of its direction in a mine. The measurements taken on main mine fan are processed based on the methods of mathematical statistics. The results allow evaluating the natural mine draft at the preset confidence coefficient, and the offered algorithm enables on-line control of mine ventilation.

The article describes studies into morphology of gold in the initial ore and mining-generated silt in the weathered crust of the Yenisei Range using the methods of optical and electron microscopy. The authors have determined sizes and shapes of gold grains, nature of intergrowth of gold, ore and rock-forming minerals, and microadmixtures characteristic to free gold particles discovered in the initial ore and in old tailings pond.