Information modeling of a geomechanical space

An approach to information modeling of geodynamic processes in a rock mass is proposed. The mathematical methods developed for 3D modeling of geomechanical objects are based on the triangulation by the defined set of revision points obtained from layouts of levels; the information model data base design is described. The information model implementation for the conditions of the Tashtagol ore deposit is presented. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 84–98, March–April, 2007.     

Method of preparing data for solution of three-dimensional geomechanical problems

Conclusion A nontraditional monitoring procedure, which is based on the use of three-dimensional geomechanical models constructed in accordance with the hierarchical principal, ensures quantitative estimates of the stress-strain state of a mass, which assume practical significance. The algorithm that we have developed reflects the sequence of data preparation for the construction of a model and numerical analysis of stress fields using an original software package developed at the Mining Institute, Siberian Branch of the Russian Academy of Sciences. A different kind (geological, geophysical, and seismological) of data, which directly or indirectly characterize the field of stresses acting in a mass, and the adequate scale of the model is considered in formulating boundary conditions in models. A method is proposed for adapting a geomechanical model to actual conditions of the state of the mass, the essence of which is included in a correction to the model stress field by consideration of field stress measurements with subsequent solution of the inverse problem and the formulation of new boundary conditions. In addition to the solution of geomechanical problems in mining, the approach that we have developed to the construction of models may be used in organizing studies on the observation and prediction of extreme natural and man-made situations on the territorial and regional levels. Mining Institute, Siberian Branch of the Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 12–21, May–June, 1997. The study was performed with financial support from the Russian Fund for Fundamental Research (Grant No. 05-95-15604).     

Application of laser scanning for developing a 3D digital model of an open-pit side surface

A method is described for the 3D survey of an open-pit side surface by using a laser scanner in order to develop a 3D digital model for identification of the hierarchical structure of geoblocks at a limestone deposit. The main principles of the laser scanning are explained, recommendations are given for the selection of the scan stations arrangement to survey a vertical open-pit side. The computer-aided scanning-data processing technique is presented for the graphical-analytical representation and system analysis of the experimental geomechanical information on the real rock mass. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 102–112, September–October, 2007.     

Rock movement at the Tashtagol iron-ore deposit in the course of large-scale underground blasting

The paper describes the results of studies into the processes of deformation of rock masses near protected objects and in mine workings of the Tashtagol iron-ore deposit, carried out with the conventional geodetic methods and the GPS-techniques. It is shown that rock mass movements in the periods of large-scale blasting mostly take place along flat-dipping tectonic faults and in the line of action of maximal stresses in the intact rock mass. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 25–33, May–June, 2008.     

Sudden outburst of coal and gas — failure of natural coal as a solution of methane in a solid substance

Basic Conclusions  1. The methane dissolved in natural coal may participate directly in the dynamic failure of the coal during sudden outbursts. 2. The following are factors determining the participation of dissolved methane in the failure of coal during outbursts: a high natural methane content, the fracture microstructure of the coal, and its low crack resistance. 3. It can be stated that it is precisely the dissolved methane that predetermines the formation of "mad flour." The author expresses gratitude to S. V. Kuznetsov, V. A. Bobin, I. V. Zverev, V. A. Trofimov, and M. O. Dolgov for their discussion of the study. Institute of Problems of the Complex Exploitation of Mineral Resources, Russian Academy of Sciences, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 18–28, November–December, 1997. The study was performed with financial support from the Russian Fund for Fundamental Research (Project No. 96-05-65884).     

On information-provided monitoring of geodynamic processes in the Kuznetsk Coal Basin in the conditions of highly intensive sub-soil usage

It is shown that formation of hollows in bowels of the Kuznetsk Coal Basin (Kuzbass), induced by opencut and underground mining has reached an intensity of 1.3–1.5 million m³/day. In the conditions of high concentration of mines and open-cuts in small areas, a regional monitoring network is required in view of a generated geomechanical space, hazardous in geodynamic manifestations. A developed information support of this netwoprk is presented, including information models of a geological environment and database obtained from instrumental observations on geomechanical processes. The equations of connection between structural and strength characteristics of rocks, their metamorphization grade and occurrence depth are given for five geological-tectonic zones of the Kuzbass as a way of prediction of their properties. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 40–66, September–October, 2006.     

Feasibility study of a geotechnology for underground mining at Udachnaya kimberlite pipe under the opencast bottom

The authors offer the optional versions of mining methods and technological schemes for mining at Udachnaya pipe reserves under the opencast bottom. The rational chamber-and-pillar method has been substantiated, considering the complicated mining-geological and geomechanical condition at the deposit. The economical feasibility of the proposed underground mining variants has been evaluated. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 55–67, May–June, 2008.     

Geomechanical conditions for quasi-resonances in geomaterials and block media

Conclusions  Based on voluminous information about relations between the dimensions of the central zones of crustal earthquakes and various energy classes of underground explosions, as well as mine shocks and man-induced tremors, therefore, the hypothesis that we had previously advanced relative to the quasi-resonant mechanism of their manifestation is confirmed. Here, the geomechanical conditions for the development of quasi-resonances associated with the inducement of pendulum waves are characterized by the dimensionless energy criterion k:

Geomechanical state of the rock mass at the Tashtagol Mine in the course of nucleation and manifestation of rock bursts

Integrated research data are presented for the earth motion and rock mass displacement at the Tashtagol Mine under general intensification of the dynamic geomedium activity, including periods of rock burst developments, by using conventional and satellite geodesy procedures. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 38–46, March–April, 2008.     

Evaluating the residual life of salt pillars

Conclusions Thus, the completed studies have made it possible to develop a technology and methodology, based on the compensation method, for measuring the load on the edges of inter-chamber pillars. An experimental-theoretical method has also been proposed for estimating the residual life of such pillars in excavated sections of potassium mines. The results of full-scale measurements established that the edge regions of interchamber pillars located near the boundary of a cave-in (region of chamber 103 in our investigation) are in the supercritical state. For a subsidence rate of 1.5 mm/day at the surface, the residual life of such pillars is estimated to be 7–8 months. The zone loaded by bearing pressure from the caved-in rock is shifted toward the interior of the goal (regiona of chamber 120). The load factor of the pillars exceeds the allowable value [C]=0.4 specified by standards for “rigid” interchamber pillars in the mines of the Verknekamsk Potassium Salt Deposit, which accounts for their “compliant” regime of deformation. Thus, to reduce the strains of the water-protective stratum and prevent water above the deposit from entering the mine, the region of chamber 120 must be filled. Mining Institute, Ural Branch of the Russian Academy of Sciences (Perm). Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 18–25, January–February, 1998. The theoretical part of this investigation was completed with financial support from the Russian Fund for Basic Research, Grant No. 96-05-64849.     

Modeling of initial stresses and weakening surfaces by finite-element method

Solutions of geomechanical problems in terms of full and additional displacements are compared for the example of the creation of the mined-out space filled with stowing and the construction of a subway tunnel. An approach to modeling the contact interaction of a block massif is proposed. Data on the stress-strain state of rock mass in forming the mined-out spaces close to extended geological disturbances are presented. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnichskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 49–59, March–April, 1999.     

Results of the integrated geophysical and geodetic investigation of the stress-strain state in Tashtagol Ore Field

The paper describes observations over the gravitation and electromagnetic field variations in a 900 m deep opening in Tashtagol Iron Ore Mine, as well as monitoring of movements in the rock mass and on the earth’s surface. The results provide characterization of the variability of the stress-strain state in the rock mass, and the rock pressure manifestations in the mining area. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 31–39, May–June, 2009.     

One approach to the prediction of rock bursts

Conclusions Thus, as a result of the experimental discovery of previously unknown pendulum waves, the elementary carriers of which are geoblocks differing in hierarchic level, with dynamic-kinematic characteristics that depend on the stress-strain state of the rock masses and the dimensions of the focal zones of rock bursts and explosions, we are able to propose a new approach to the prediction of catastrophic events. Here, as diagnostic indexes with respect to the critical stages of stress concentration for focal zones of rock bursts that are being formed, we can use the angular characteristic θ of the conical envelope of the μ-wave packets and their energy characteristics Ψ₁ and Ψ₂. With such an approach, seismograms from technological explosions can be used as integral information in a new system of geomechanical monitoring. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 3–15, November–December, 1998.     

On some features of evolution of harmonic acoustic signals in loading block media with a cylindrical cavity

The results are presented for physical modeling, which make it possible to answer a question whether there are any bases for the hypothesis (proposed by M. V. Kurlenya and V. N. Oparin) that at the prefailure stages, the focus zones of rock bursts, earthquakes, and other dynamic events become similar to a peculiar “geomechanical laser system,” i. e., an acoustically active medium capable of coherent seismic-energy radiation. In this context, possible consistency of the acoustic signals formed in structural elements of block media, in terms of both the frequency spectrum and the phase component, is a key issue. In existing approaches to the analysis of the mechanisms of focus zones of dynamic rock-pressure manifestation, as a rule, the fact that quasi-static processes of elastic energy accumulation in the forming focus zones always proceed against an acoustic background (from natural microseisms to complex wave phenomena accompanying pulsed seismic effects from remote earthquakes, explosions, etc.) is ignored. In view of the anomalously low friction in block media (discovered at the Institute of Mining, Siberian Branch, Russian Academy of Sciences), the type of the stress-strain state in geoblocks and the amplitude-period characteristics of the “seismic background” may be decisive in the realization of dynamic event. Therefore, it is natural to ask what happens, for example, to microseisms or acoustic wave packets, that are regular in frequency, in the focus zones of future dynamic events depending on the level of stresses prevailing there. Experimental data are considered for one of the most simple cases where the focus zone is modeled by a set of homogeneous blocks with a stress concentrator in the form of a cylindrical cavity (a “plane” model), while the quasi-static process of external loading is represented by uniaxial compression from a press with weak lateral thrust. The “acoustic background” is specified in a peripheral block of the model in a monochromatic regime. This model relates directly to the acoustic monitoring of the limiting states of rocks around underground workings. It is proved that the prefailure stages of model are characterized not only by convergence of the resonance frequencies in the block system but also by amplification of the harmonic-signal amplitude due to conversion of the stored elastic energy of the structural elements to energy of acoustic signals. The law of exponential decay of harmonic signals from a radiation source is violated here, and the model of the geomaterials becomes an acoustically active medium operating as a peculiar “geomechanical laser system.” Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 10–32, November–December, 1999.     

Longitudinal multichannel optoelectronic deformometer

Conclusion Based on laboratory and full-scale (on-site) tests, the developed basic model of the MOéD-Ip longitudinal-type multichannel optoelectronic deformometer appears to match its design specifications. Laboratory experiments using acoustic channels have demonstrated the unique possibility of application of individual measuring modules of the MOéD-Ip instrument system for diagnosis and monitoring of the state of block media in terms of their loading stages. Based on full-scale (on-site) experiments in the Borok quarry, absolute deformations in rock mass due to blasts of different power under set conditions have been recorded for the first time. We believe that this technical development will find wide application in both mining and civil engineering for monitoring of the effect of blasts, earthquakes, and other factors on the state of natural or engineering structures. In this context, special stress should be laid on integrated application of deformographic and acoustic measurements. The procedure of processing and joint analysis of physical information proposed in this paper is indisputably novel and promising for practical applications. We express sincere appreciation to V. I. Shut and V. K. Pakhotskii for their great help in constructing the MOéD-Ip instrument system as well as to the specialists of the Novosibirskvzryvprom (Novosibirsk Blasting Industry) B. P. Raspopov, I. A. Aleksandrov, P. V. Kobelev, and V. N. Yurchenko for their help in organizing and performing on-site experiments at the Borok quarry. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 105–119, May–June, 1997. This work was financially supported by the Russian Fund for Fundamental Research (Grant No. 96-05-66052).     

Effect of oil field development on the geodynamic state of the interior of the earth

Conclusions Thus, the geomechanical analysis performed suggests that hydrodynamic impact of oil field development on dislocational break is a potential cause of technogenic seismic phenomena. For the discussed variants of calculation the magnitude of these events is rather insignificant. Unquestionably, the data obtained are preliminary because account has not been taken of the whole diversity of technological variants under conditions of complex deep structure of the rock mass. Possibly, in these cases the consequences of changes in the geodynamic situation may be more significant. Further studies should be continued in the direction of refinement of the geophysical model, for which it is necessary to obtain more comprehensive and precise information about the change in the dynamics of subterranean water under the influence of oil field development as well as about the structure of the rock mass, natural stress field, technological parameters of exploitation of the field, and so on. This will make it possible to raise the adequacy of the geomechanical model and to get more reliable prognostic assessments of the geodynamic consequences of oil field development. Institute of Mining, Ural Branch, Russian Academy of Sciences, Perm. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, Vol. 34, No. 2, pp. 31–42, March–April, 1988.     

Improvement in ore beneficiation technology of complex substance composition

The results are presented for investigations on improving beneficiation process of mineral raw material of complex composition by way of example of rebellious polymetallic ore from the Zhairemsky deposit. It is found that the production of conditioned collective concentrates by accelerated electron action is accompanied by reduction in losses of lead and zinc with the tailings that are 2–3 times less than in direct selective flotation. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 97–102, September–October, 1999.     

Substantiation of the sequence for opencast mining of a series of flat and inclined strata using the mined-out space for internal dumps

The possibilities of using the mined-out space of opencasts for placing the overburden in internal dumps are studied. It is established that on completion of mining flat and inclined strata there are free capacities in the mined-out space consisting of 40–70% of its volume which are a resource for placing the overburden from other opencasts with substantiation of the sequence of mining large deposits. A complex criterion is suggested that takes account of energy expenditures for mining a deposit and the energy damage caused to the environment. A procedure is given for solving the problem and results are presented of calculations for the Taldinsk and the Tomusinsk deposits. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 97–106, May–June, 1999.