Vol 53, No 1 (2017)

The generalized observations over hypocenters of the strongest mining-induced events have shown that relative deformation occurs as movement along the existing faults. From the experimental evidence, transition of a section of a fault to meta-stable state goes with the decrease of its dynamic shearing stiffness. The alteration of the mechanical properties starts long before macroscopic movement of the fault surfaces is recorded. This effect is detectable using instruments and can be used as a foundation for a new approach to monitoring of induced earthquakes.

This paper presents one strain gradient model of zonal disintegration of rock mass near deep level tunnel. The governing equations and boundary conditions of the model are established. Numerical methods (quasi-Newton method and shooting method) are adopted to solve the obtained fourth-order equilibrium equations with higher order boundary conditions in terms of displacement. The stress field in elastic and plastic zones is obtained. The effects of model parameters on stresses distribution in surrounding the tunnel rock mass are examined. The necessary conditions for the formation of zonal disintegration are elucidated.

The calculations of stress state and failure of rock mass in the vicinity of longwall in a coal bed with the high gas content in Polysaevskaya Mine, SUEK-Kuzbass, are described. The effect of the mining depth and coalbed gas pressure on the geomechanical situation in the longwall is illustrated. The authors discuss scenarios of directional crack formation in front of the longwall.

Numerous abandoned workings, mostly tunnel ones, are present in post shallow mining areas. The loss of stability of an excavation and its failure is often a cause of sinkhole formation at the surface, sometimes even many years after mining activities were discontinued. This paper presents a method of predicting the probability of sinkhole formation based on Salustowicz’s theory as well as its practical application using a computer program.

Under numerical investigation is propagation of surface pendulum waves in 3D block medium. The medium is modeled by 3D lattice of masses connected with elastic springs and viscous dampers. The surface vertical pulsed concentrated loading is considered. The displacements and velocities of the surface masses are calculated. The numerical results obtained for the block medium are compared with the similar data on elastic medium and in situ experiments carried out by other researchers.

The article reports basic design parameters of open pit mines of ALROSA, as well as criteria and factors that govern the choice of production capacity of an open pit diamond mine under conditions of permafrost. The analytical relations and tables to calculate open pit mine life are presented, and the influence of the rate of the downward advance of an open pit mine on its capacity is demonstrated. The authors formulate key provisions for a paragraph of the national standard of RF enabling systematization of approaches to optimization of open diamond mining parameters.

The authors propose a promising approach to reduction of the environmental impact of open pit mineral mining—robotic automation of geotechnologies. The objectives, techniques and advantages of introduction of industrial robots are discussed. The analysis of development and improvement of geotechnical system reveals factors that limit application of mechanized, automated and robotic equipment. The structural elements of geotechnical system using mechanized and robotic mining and transportation machines are compared.

A significant quantity of available hard coal reserves in the area of Upper Silesian Basin in the Czech Republic occurs below the areas where surface mine subsidence is unacceptable or may be only minimal. An effort is made to mine these reserves by means of a new, mining method yet not approved for the joint-stock company OKD, a.s., namely a special modification of the continuous mining method Room & Pillar. The main objective is to eliminate the mentioned surface restraints by leaving stable pillars of coal to support the overlying strata. The article is based on [1] published in Journal of Mining Science in the year 2015. In the article the authors are concerned with the description of stress–strain monitoring of pillars left after test operation, including its continuous evaluation and evaluation of important operating conditions and activities.

Design of an air drill hammer with the smooth adjustment of the percussion frequency at the constant blow energy is considered. The proposed and analyzed modifications of air distribution system are based on using a mechanically closing elastic valve. The test data on experimental prototypes of the air drill hammer with the external distributing elements that set blow frequency are presented. The frequency adjustment ranges are determined.

The structural and chemical surface transformation of basic kimberlite-forming minerals (calcite, olivine, serpentine) under the contact with natural and waste mineralized water and products of electrochemical treatment of the water are studied using X-ray photoelectronic spectroscopy, scanning electron microscopy and X-ray spectral micro-analysis, and atomic force microscopy. It is found that contact with kimberlite extract and recycling water induces chemical modification of calcite surface, which consists in adsorption of hydrocarbon impurities, and chlorine- and silica-bearing compounds, majority of which are removed during interaction with the product of electrochemical treatment of recycling water. The change in the structural and chemical surface properties of rock-forming silicates, aside from adsorption–desorption of organic compound, is also connected with the distortion of nano-size layer structure after leaching of Mg, Fe and Si, and with the carbonatization of the surface.

The article focuses on concentrating of nickel from lean solutions of leaching of oxidized nickel ore. The proposed block diagram of process flow chart for such solutions includes hydrolytic removal of admixed iron and aluminium and precipitation of nickel concentrate by calcinated magnesia. As a result, nickel content of the concentrate is 26–26% at the recovery of 95–97%. The issues of decontamination and recycling of the solutions are solved.

The authors describe studies into dressability of mill tailings from tailings pond of processing plant of Yaroslavsky Mining Company. It is found that the mill tailings contain 14.92% of CaF₂, 13.16% of CaCO₃ and 0.49% of Zn. The use of new compositions of modifiers in flotation of fluorite allows production of standard grade concentrates with CaF₂ content of 93.19–95.54% at the recovery of 52.75–30.15%. Zinc recovery is 38.84% with the yield of 42.11% Zn concentrate.

The environment protection and dust control on washed-in waste piles is complicated by the continuous replenishment of tailings and, consequently, formation of new dusting layer on the pile surface. This problem can be solved using aerosol guns–fogging machines devices within the dust suppression system. The authors propose to place the aerosol dust suppression system on a platform–car moving along a tailings dump. This allows automating dust control and increasing volume of transported water. Grain-size composition of dust at tailing dumps of Kovdor Mining and Processing Plant is determined. From the laboratory experiments, it is found how intensity of dust transfer abates dust suppression. The experimental findings make it possible to calculate the required number of jets for an aerosol gun.

Geophysical methods of detecting places of spontaneous heating in mined-out voids in gently dipping and inclined coal beds in Kuzbass mines are reviewed. The emphasis is laid on the method of equatorial dipole sounding used to determined temperature of coal in the place of spontaneous heating in Olzherasskaya Novaya Mine. The cooling time of the coal and rock nest down to the temperature of surrounding rock mass is estimated, and the self-heating seat suppression actions are proposed.

Samples of rocks with different physical properties (three kinds of granite, marble and quartzite) were subjected to destruction by impacts. Fractoluminescence was recorded on the damaged surface, and amplitudes and frequencies of series of light pulses were determined. On all test samples, initiation of intergrain cracks was observed. Defects on the surface of grains in granite samples had two typical sizes conformable with defects in quartz and spar, while uniform content minerals (marble and quartzite) features unimodal distribution of sizes of defects on the surface of grains.