Home – Home – Jornals – Journal of Mining Sciences 2014 number 5

In focus are the applied problems of the mechanics of granular media in the context of mining engineering. The author illustrates the relationship of the mechanics of granular media, plasticity theory, rock mechanics, synergetics and other sciences. Trends of the further research effort are indicated.

The authors comment on features of formulation and structure of input data for the inverse problems used in rock mechanics to estimate state and properties of natural and anthropogenic objects at various spatial scales. The article gives examples of using solutions of inverse problems in coal bed degassing monitoring, by data on changes of pressure in hydraulic props on the overlying bed, and in assessment of deformation parameters of inclusions, by data of uniaxial compression tests of artificial heterogeneous samples.

The author analyzes the data of biaxial tension test of 40X steel carried out in the Institute of Mining. A proper tensor basis, where relations between increments of stresses and strains are independent of the type of loading and additional loading, is found.

The article presents a discussion of formulations and methods of solving of problems on stress-strain state of surrounding rocks and solidifying backfill developed in the Institute of Mining. As shown, effective algorithms can be obtained with the use of a computational domain that conforms with the rock mass before the first and second mining. The process of driving and backfilling is modeled using the iteration procedures from the initial stress and strain methods. Convergence of the offered iteration procedures is confirmed. Solution of practical problems is exemplified. In the framework of the developed methods and algorithms, the author offers the ways of accounting for incomplete backfill with solidifying mixtures and for rheological properties of surrounding rocks and the backfill

The article addresses the issues of geomechanical monitoring in underground mineral mining. A brief review covers existing software and hardware for estimation of stress state and properties of rocks and the results of in situ trial of an integrated tool set. The authors offer the geomechanical monitoring structure using a package of instrumental, visual and numerical methods for the assessment of mechanical condition and its alteration in rocks and in structural components of mines. Thereupon, the geomechanical state control system have been developed and introduced in a number of operating mines. For the stability assessment of structural elements in mines and for the decision-making on mining safety, the rock mass limit state criteria are defined.

The article deals with the interaction between the groups of explosive charges installed at the free surface of rock exposure along the open pit mine perimeter. The spectrum analysis of the explosion-induced seismic waves shows that peak density frequency of the seismic waves are governed by the formation of the canonical low-frequency components as a result of successive actuation of explosive charges, and are conditioned by hierarchical block structure of blasted rock masses.

The authors report geomechanical evaluation of rock masses. The flow charts and parameters of geotechnology for ore extraction by blocks and sections under conditions of rockburst hazard are presented. It is stated that the use of the new mining and blasting technologies results in appreciable economic effect.

The authors show the basic ways of making hard mineral mining by open pit method more efficient. The article gives a review of research aimed at improvement of open pit mining methods, intensification of mining, enhancement of mine safety and final product quality control (in terms of Bakcharsky iron ore deposit and coal deposits in the Kuznetsk and Kansk-Achinsk Coal Basins).

The article gives an account of process designs accepted and introduced in mines at Norilsk-1, Talnakh and Oktyabrsky deposits and describes new promising patented mining methods successively trialed at a commercial scale or proposed for industrial testing.

The discussion covers the issues of difficult caving roof control in production faces and coal bed degassing. The methods and means meant for the directional hydraulic fracturing and coal degassing are described. The practical results of the method introduction in coal mines in Kuzbass are reported.

The article concerns with the problem of blow energy increase at the confined air consumption in air hammers used in special underground construction. The solution is the air distribution circuit with an elastic ring valve installed in the back stroke chamber; the valve is closed under mechanical contact with the air hammer housing and opens under action of the elastic force of the material the valve is made of. The use of such valve enables relief of the backward pressure during the direct stroke of the hammer and allows the back stroke length adjustment, which ensures the constant blow energy at the varied air flow.

The energy upside potential of downhole air hammers is considered. The article presents the constructional diagram of a new air hammer using high compressed air pressure (up to 3 MPa). The experimental testing of the operating cycle of the air hammer is reported. The authors ascertain the air hammer steel requirements and the steel heat treatment modes to enable extended life of the air hammer parts. Industrial trials of the air hammers are described.

The authors analyze the existing motor equipment for safe dumping and offer a new engineering decision to the problem using vibrating overburden spreaders.

The article describes the full-scale tests on temperature in tunnel lining and adjacent soil in shallow subways operating in the extreme continental climate conditions. The mathematical modeling of air flow in the subway tunnel ventilation is presented. The authors have worked out recommendations on architectural concept of escapes from a subway platform. The system offered for air flow control in a ventilation branch consists of a platform fan delivery control channel and a tunnel air flow control channel.

The article presents the theoretical and experimental research findings aimed to create a basis for the development of innovative integrated processing technologies for complex ore and mine waste. It is found that introduction of nonmechanical energy treatment by an accelerated electron beam in the ore dressing circuits increases rebellious mineral processing data. The features of a flotation unit process are analyzed from the viewpoint of improvement of collecting and selecting abilities of a reagent and relationship between these abilities and molecular structure of the reagent. The authors define flotation activity of reagents and offer a flotation contact formation criterion. It is proved to be effective and promising to use magnesium- and manganese-bearing minerals for sorption purification of mine effluents in order to reduce metal loss in the wastewater discharge and to minimize damage of natural water bodies.

The article presents guidelines, test model design and barrier shield design model aimed to improve quality of sealing of coal bed methane drainage holes by the barrier shielding method.