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The article describes the development stages of an adequate regulatory structure for the slope stability in open pit mines. Some supplementary factors that have influence on stability of slopes in open pit mines in the gravity-tectonic stress field are discussed. The main trends of research of pitwall rock mass in operating surface mines are presented, and the necessity of determining the tectonic stresses in pitwall rock mass and taking into account their impact on slope stability is emphasized. The algorithm is developed for justifying slope parameters for open pit mines under tectonic stresses, the drilling-and-blasting principles are formulated for the operation in pitwall rock mass, and the methods are proposed to mitigate the blasting-induced impact on adjacent rocks.

The article addresses the problem on thermal stresses and stress-strain behavior of rock mass during deep-level mining. The author proposes an approach to determining the stationary field of temperatures in the zone of mining with cemented paste backfill with single formation of stiffness matrix in the calculation. It is found that inclusion of the temperature change depthward rock mass in the analysis results in the increase in the initial horizontal stresses while the initial vertical stresses remain unaltered. The calculation method of stress redistribution in the course of mining with backfill, with the same stiffness matrix used at all calculation stages, is modified for taking into account the thermal stresses. The calculation of the thermal stress state of surrounding rocks and backfill is carried out for a variant of mining with backfill in a gently dipping ore body.

The mathematical modeling of creep and long-term strength of rocks uses the non-associated flow rule. The authors propose a unified approach to the plasticity and creep processes. The theoretical calculations are compared with the testing data of different materials. In creep deformation in rocks, the applied problems on limit state of rock mass in plain strain are considered: pressure applied by a solid die block with flat bottom on rock mass limited by a horizontal plane and occupying the bottom part of a half-space; instability of pit wall or natural slope under different loads. These problems evaluate stresses in the limit state zones and the times-to-failure in rocks mass with regard to internal friction.

The article discusses tectonic stresses determined in the West Sakhalin terrain using different tectonophysical methods. The reconstruction of the stress field in coal fields in Sakhalin is implemented using the graphical method of orientation finding of stress axes in fractures and faults (at 16 observation points). The supplementary on-site tectonophysical studies made it possible to estimate the preferred orientation of the main slickensides of different kinematics and to reconstruct on this basis the local stress tensors at 53 observation points. The typical stress state of the West Sakhalin terrain is horizontal tension.

The features of mining of a coal series are described. The stress-strain behavior of rock mass during mining of the lower strata in the series is assessed with regard to the influence of coal pillars and upper level roadways. Different variants of location of a temporary roadway on the lower stratum in a series protected by a pillar are discussed. The implemented prediction of the stress-strain behavior of rock mass is adapted to the conditions of mines in the south of Kuzbass. This prediction is used to select the geomechanically safest variant of location of the temporary roadway.

The article describes the studies on permeability of coal cores with a through drainage fracture with and without a monolayer of a proppant. The experimental procedure is descried. The parameters of the jointed structure of test long-flame coal are given. The efficiency of wedging drainage fractures by a sparse proppant monolayer in building up permeability of deep-seated coal is demonstrated.

The authors provide the theoretical and experimental justification for the effective methods of modification of saponite-pillaring and thermal treatment-which ensure production of sorbents possessing high cation exchange capacity relative to cations of heavy metals. The mechanism of pillaring and thermal modification of a saponite-containing product at the temperature of 625 °С involves expansion of layers of the mineral, formation of additional acid or redox sites (pillaring) and restructuring with generation of metastable phases (thermal treatment). Modification of saponite increases static exchange capacity relative to copper cations by 2 times after pillaring and by 2.6 times after thermal treatment.

The main mechanisms of flotation activation by ions of metals are discussed and critically analyzed. It is shown that ions of metals can be both activators and depressants of flotation. Based on the mechanism of physisorption, it is revealed when metals act as activators and depressants. A method is proposed to stimulate selectivity of extraction of a target mineral in case of undesirable activation of flotation of associate components. The studies can be useful in selection of metal-activator, ratio of concentrations of activator and collector and pH of flotation system.

The author investigated the modes of thermal and heat-and-radiation treatment of ferruginous bauxite from Vezhayu-Vorykva deposit and revealed different mechanisms of mineral transformations. Under thermal treatment, oxo-hydroxides transform into anhydrous iron and aluminum oxides, while under heat-and-radiation treatment, scattered microelements form metal alloys and new minerals. It is recommended to ground ferruginous bauxite processing on basic science, first of all, nanomineralogy, and on phenomenon of phase heterogenization. This approach can promote an increase in recovery of fine particles of aluminum and other valuable components from low-grade bauxite and red mud by eco-friendly techniques.

An assessment of the state of forest lands disturbed by fires, logging and insects in the foothills of the Eastern Sayan Mountains in the forest formations inherent in the study area (Siberian stone pine ( Pinus sibirica Du Tour), fir ( Abies sibirica Ledeb.), Scots pine ( Pinus sylvestris L.), spruce ( Picea obovata Ledeb.), larch ( Larix sibirica Ledeb.), birch ( Betula pendula Roth), aspen ( Populus tremula L.)) as well as in forest crops was carried out. The impact of fires, insects, logging, and windfalls was found to result in degradation of the forest health conditions of all forest formations within the boundaries of the foothills of the Eastern Sayan Mountains. Characteristics of natural reforestation on disturbed areas of forest lands were revealed. Unsatisfactory reforestation was observed on most of the disturbed areas of forest lands due to proliferation of the dense grass cover, the formation of a thick duff, the growth of sphagnum (Sphagnum L.) and the occurrence of frequent fires. In cases where there is a sufficient amount of healthy regeneration, natural reforestation occurs by vegetative propagation of soft-leaved low-value tree species (birch and aspen), which, in turn, inhibit the young immature generation of coniferous trees (including forest plantations) due to shading and competition for soil nutrients.