2. Results of the using theoretical principles for the analysis of active monitoring of mountain massifs under technogenic impact

One of the fundamental problems of mining, which is traditionally attributed to the problems of geomechanics, is the development of theoretical and experimental

methods for studying the structure and state of rock massive with a view to predicting and preventing catastrophic phenomena in the mining of deposits. This problem is complicated by the fact that the rock massif is influenced by direct or indirect technogenic impact, which leads to a significant non-stationary of both the structure and the state of it. The ideological inspirer of the search for integrated geophysical and geomechanical approaches to the solution of this problem in the Ural was N. P. Vlokh [18]. An analysis of the manifestations of mountain impacts in the mine workings of the Oktyabrsky deposit of the Norilsk ore site showed that more than 60% of them are confined to tectonic disturbances. Peeling and intensive incineration occur mainly in excavations located outside the zone of influence of clearing works at a distance of 10–12 m from the surface of the tectonic disturbance. In the ores and rocks of medium disturbance, the dynamic phenomena dominate in the areas of interface of the excavations and are accompanied by collapse of the massif. When intersections with excavations of areas of the massif with irregularities have two or more planes of displacement, with a zone of crumpled and fragmented rocks, collapse from the roof and collapses from the sides are observed, accompanied by a dynamic effect and reaching considerable volumes [19]. When conducting mining operations in high-stress rock massive, technogenic seismicity is manifested, with forecasting and prevention issues being given much attention in all countries with a developed mining industry. An important role here belongs to the short-term forecast; the methodology for identifying criteria for it is still a problem, both in mining and in seismology [20]. From the point of view of the paradigm of physical mesomechanics, which includes a synergetic approach to changing the state of rock massive of different material composition, this problem can be solved with the help of monitoring methods tuned to the study of hierarchical structural media [13, 21]. Changes in the environment, leading to short-term precursors of dynamic phenomena, are explained within the framework of the concept of self-organized criticality [17, 20], for which mainly significant moments are heterogeneity and nonlinearity [13].

Within the framework of the IGD SB RAS School, important results have been achieved in studying the state of the rock mass within the framework of nonlinear geomechanics [22] using geophysical methods that have the resolving power to detect the nucleation and decay of self-organizing structures [23].

For the first time, using the electromagnetic method developed in the IGF UB RAS, it was possible to realize the idea of identifying zones of disintegration in an array of rocks within the framework of field studies [24, 25] and to monitor their morphology [26]. The technique used relates to geophysical methods of nondestructive testing. It differs from the previously known methods of semitransparency or tomography by observation systems and the subsequent interpretation method based on the concept of three-stage interpretation [27]. In [28] the first full-scale results on the detection of the self-organization phenomenon in a rock massif with anthropogenic impact and the method of developing stability criteria based on the proposed classification methodology had been represented. These results were obtained on the basis of analysis of several cycles of electromagnetic monitoring of the massif of the shock-dangerous Tashtagol underground mine, conducted in 2000, 2001, 2002, 2003, 2004, and 2005 in a number of excavations located on four horizons at depths from 540 to 750 m in order to reveal the morphology of the zones of disintegration in the near-working space in a rock massif that is under intense man-caused impact and the influence of the natural stress field. In the work [23], studies were conducted aimed at developing criteria for spatial–temporal complex active and passive seismic and electromagnetic monitoring to prevent destructive dynamic phenomena based on 6-year seismic monitoring data conducted by the service of rock shocks in Tashtagol underground mine and the experience gained

### Analysis of Seismic Responses of Rock Massif to Explosive Impacts with Using Nonlinear Methods DOI: http://dx.doi.org/10.5772/intechopen.80750

using the IGF UB RAS systems of induction electromagnetic space–time monitoring on arrays of various material composition before and after mass explosions.

We analyzed the morphology of the structural features of the disintegration zones before a strong dynamic phenomenon during the next cycle of electromagnetic observations at the Tashtagolsky mine during August 2007. On August 9, there was a rock explosion with the energy: lg E = 6.9 in the range of the ort 3 at a level of 16 m below the horizon ˜280 (Figure 1), N = 108 (Figure 2(a) and (b)). The analysis of the second curve (Figure 1) demonstrates the irregularity of the number of weak dynamic phenomena in the array of the entire mine field with energy lgE < 6 in time. So, after a mass explosion on the same day, 42 phenomena were registered, for the next day, already 17, and then this number in the next day is even more reduced. Before the rock impact, there is a significant rarefaction of the number of dynamic phenomena—a zone of calm. During the day, when there was a rock shock after it, 12 weak dynamic phenomena were observed, similar to how it happened on the third day after the mass explosion.

Three days before the rock shock in the ort 4 (Figure 2(a) and (b)) in the geoelectrical sections of the massif, subvertical discrete structures are found, into which disintegration zones have merged. These structures manifested themselves in a resonant mode at different frequencies and only at one frequency for each of the units. We discovered the same phenomenon earlier during one day at the mine Estyuninsky and SUBR (mine15) [21] (Figure 3).

Regarding Figure 4 we see the comparative data from 2000 to 2007 the distribution of the parameter of the interval intensity Spint (in 2007 the results were given according to the electromagnetic measurements before and after the rock shock) in the bottom of the Ort 2 of the massif, horizon ˜210 at two frequencies: 5.08 and 20 kHz. According to the classification [29], the state of the array of the Ort 2 was defined as quasi-stable. The obtained results show that, despite the very close location to the site where the rock shock occurred, the massif remains practically in a state described by the gradation quasi-stable. For the period from August 2 to August 13, 2007, the maximum of the parameter Spint moved from the fourth interval (3–4 m) to the first (0–1 m) without increasing its amplitude. The emergence of these structures of subvertical morphology is a forecast of a strong dynamic phenomenon; however, in order to determine the place and magnitude of an event, it is necessary to have information on the state of the arrays and their belonging to the appropriate ranks of stability of the array, as was done in [29].

#### Figure 1.

The distribution of the dynamic phenomena in the Tashtagolsky mine after the mass explosion (N = 1). (Data from the seismological catalog of the Tashtagolsky mine (authors Klimko V. K., Shipeev O. V.)).

#### Figure 2.

Geoelectric sections along the profile ort 4, horizon ˜210, northwestern section. (a) August <sup>6</sup> and (b) August 8, <sup>i</sup> 2007, frequency: 10.15 kHz. Legend: <sup>M</sup><sup>~</sup> <sup>=</sup> M0 ° L0 ° <sup>10</sup><sup>3</sup> , where M0 is the coefficient by which the moment of <sup>0</sup> the electric current line is multiplied by the influence of the zone by the parameter of geoelectrical heterogeneity equivalent over the field and which is proportional to the ratio of the conductivity difference of the disintegration zone to the conductivity of the surrounded medium, L0 is the length of the current line, and the resistance of the section is given in ohms. Vertical values are given in m (absolute marks), horizontal axes and output length in pickets (pc) and meters.

Thus, the introduction of the proposed integrated passive and active geophysical monitoring, aimed at studying the transient processes of redistribution of the stress–strain and phase states, can contribute to the prevention of catastrophic dynamic manifestations during the development of deep-located deposits. Methods of active geophysical monitoring should be tuned to a model of a hierarchical heterogeneous medium.

The technology of working out ore deep-lying deposits provides carrying out of preventive and safety control measures. For this purpose, a number of the largest Russian mining enterprises have installed multichannel-automated seismic monitoring systems within the mine fields influenced by underground mining [30].

Analysis of Seismic Responses of Rock Massif to Explosive Impacts with Using Nonlinear Methods DOI: http://dx.doi.org/10.5772/intechopen.80750

#### Figure 3.

(a–c) Geoelectrical section along profile ort 3, horizon ˜210, northwestern section. (a) July 9, (b) July 23, and (c) July 26, 2010, frequency: 10.15 kHz. The legend is the same as in the Figure 2(a) and (b).

#### Figure 4.

The distribution of the parameter of the interval intensity Spint for eight observation cycles in the array of Ort 2, horizon �210,Tashtagolsky mine according to active electromagnetic induction monitoring. (a) Observations in 2000–2007 years, frequency 5 kHz. (b) Observations in 2000–2007 years, frequency 20 kHz; 2007 (1) in the legend corresponds to data before rock shock; 2007 (2) in the legend corresponds to data after rock shock. Axes <sup>i</sup> Y-SpintðN; <sup>T</sup><sup>Þ</sup> <sup>∑</sup> <sup>M</sup><sup>~</sup> ð Þ -parameter of the interval intensity of geoelectrical heterogeneities of the second <sup>¼</sup> i Nð Þ <sup>0</sup> <sup>T</sup> rank, detected by electromagnetic induction monitoring, where N is the number of the interval into which the <sup>i</sup> soil of near-working space is divided and where <sup>M</sup><sup>~</sup> <sup>0</sup> is the intensity of the disintegration zone and <sup>T</sup> is the year of observation [14].

Analysis of a large database of seismic records of shocks and rock shocks recorded by the Norilsk seismic station at the Norilsk deposit mines using the previously proposed analysis method [31] detects the pulsating seismic energy release from stressed areas of ore and rock massive from the motion of fronts of induced seismicity by the type of oscillating pendulum [32]. In the development of this result, studies were carried out to study the transient process of redistribution of the stressed and phase states of the massif between strong man-made impacts at the

## Analysis of Seismic Responses of Rock Massif to Explosive Impacts with Using Nonlinear Methods DOI: http://dx.doi.org/10.5772/intechopen.80750

Tashtagol underground mine [33]. We studied the parameters of seismological monitoring as the values of the total energy lg (Ev), extracted by the array of a specific development block in the form of dynamic phenomena after each mass explosion, the values of the absorbed array of the same energy block we define as lg (Ep), and the maximum volume of the mine field where the dynamic phenomena occur from the given mass explosion lg (Vmax).

The transient process of energy release by an array in the form of a response to anthropogenic impact is analyzed—a mass or technological explosion for the realization of a particular technological procedure (cutoff, segmenting, compensation, collapse) in the development block. The analysis of the seismic detailed mine catalog data allows us to draw the following conclusions: when working out a specific block of the array, the entire array of the mine field undergoes a change in the stress–strain and phase states from explosion to explosion; the amount of energy absorbed and delivered by the array is not equal to each other, and therefore energy accumulation takes place in the array; the process of energy release occurs with a delay and depends strongly on the gradient of the energy absorbed from mass explosions; in the array there are zones of dynamic calm; these zones should be monitored using seismic monitoring data using the parameters proposed by us; after it is out of the minimum of the lull, it is necessary to conduct a spatial– temporal active electromagnetic or seismic monitoring within a week or 2 weeks before the technological collapse, in order to identify zones of potential instability of the second rank; these zones may be after a mass explosion, timed to collapse by sources of strong dynamic phenomena; and introduction of the proposed integrated passive and active geophysical monitoring aimed at studying the transient processes of the redistribution of the stress–strain and phase states in the system of testing can help prevent catastrophic dynamic manifestations during the development of deepseated deposits. These conclusions are based on the analysis of seismological data spatially related to the array of a specific processing unit. However, analysis of seismological data shows that strong dynamic phenomena (rock shocks) can occur in a wider area than the actual block of mining and can be initiated with time lags. Within 9 years from 2000 to 2008, in the mine of the Tashtagolsky mine on four horizons in a number of excavations, active electromagnetic induction monitoring was carried out within the framework of the frequency-geometric technique. On the basis of these detailed data and their subsequent interpretation, a method was developed for estimating and classifying an array of near-working space within the limits of developing its stability in three respects relative to strong technogenic impacts during the development of large and super-large deposits. As a result, a positive verification of the site forecast and evaluation of the magnitude of the destructive dynamic phenomenon in the mine of the Tashtagolsky mine were carried out [34]. As the experience of our studies has shown, the change in the state of the system at the investigated spatial bases and times is manifested in parameters related to the structural features of the medium of the second rank. Thus, the study of the dynamics of the state and its structure and the phenomena of selforganization of the array can be conducted by geophysical methods tuned to the multi-rank hierarchical model of the environment. This conclusion satisfies the principles of the paradigm of physical mesomechanics introduced by academician Panin V. E. and his school [13], which are also a constructive tool for studying the state of the non-stationary geological environment, which is an open dynamic system [14, 27, 35]. The use of an in-plane multi-level induction electromagnetic method with a controlled source and an appropriate processing and interpretation technique made it possible to identify disintegration zones that are an indicator of the stability of the array [26]. The introduction of the integral parameter—the intermittent distribution of the intensity of the disintegration zones—allows us to

proceed to a detailed classification of the array in terms of the degree of stability, introduces quantitative criteria for this, and characterizes the stability of the array from the viewpoint of reaching the stationary cyclic position of the maximum of the parameter Spint as a function of the distance from the output Zmax. Analysis of the variance from the frequency of Zmax allows us to introduce additional gradations on the stability of the array in its detailed classification. Comparison with the data of seismological monitoring made it possible to carry out the geodynamic classification of the array using the integral parameter Sp [15].

In [35], the possibility of using the mathematical results of the developed physical and mathematical theory of the study of the state of open dynamic conservative and dissipative systems [17, 36] is shown. These include also rock massive during the process of mining. A dynamical system is understood as an object or process for which the concept of a state as a collection of values of certain quantities at a given moment of time is defined and an operator defining the evolution of the initial state in time is specified [36]. If to describe the behavior of a system, it is sufficient to know its state at a finite number of moments of time, and then such a system is called a system with discrete time. As a rule, the control of the state of a rock massif in mines is not continuous but within the framework of observation cycles or at discrete moments of time. To describe its development, differential analogs of differential evolution equations are used. Dynamic systems are divided into conservative and dissipative systems. For the former, the total energy of the system is preserved; for the second, energy losses are possible. In the appendix to our problem, when studying the state of an array that is in the process of working out, the model of the heterogeneous and non-stationary dissipative system is closest. Nevertheless, in the array can be such local parts of it, which will be described by a conservative dynamic model, i.e., model of energy balance. The analysis of the phase portrait of the dynamic system allows us to conclude that the system is characterized during its observation period. So, in conservative systems there are no attracting sets. An attractor is a subset of the phase space ΡN, to which trajectories starting in some neighborhood of it incline with time. If a periodic motion exists in a conservative system, then such motions are infinitely large and are determined by the value of the energy under the initial conditions. Attractive sets can exist in dissipative systems. Stationary undamped oscillations for dissipative dynamical systems are not characteristic. However, in nonlinear systems it is possible to have a periodic asymptotically stable motion, in the mathematical image of which is the limit cycle, represented in phase space by a closed line, to which trajectories from some neighborhood of this line are contracted with time. In terms of the shape of the phase portrait, one can judge the characteristic behavior of the system, and the "smooth" deformations of the phase space do not lead to qualitative changes in the dynamics of the system. This property is called the topological equivalence of phase portraits. It allows you to analyze the behavior of various dynamic systems from a single point of view: on its basis, the set of dynamical systems under consideration can be divided into classes within which systems demonstrate qualitatively similar behavior. From the mathematical point of view, the "smooth deformation" of the phase portrait is a one-to-one and mutually continuous transformation of the phase coordinates, as a result of which new singular points cannot appear, and on the other hand, singular points cannot disappear. The earlier results of the study of the phase state of the rock mass [15] indicate that the classification of the massif with respect to its stability and its further control can be very effectively carried out using the parameter Spint-interval intensity of second-rank heterogeneities or, according to the terminology adopted in geomechanics, the disintegration zones.

Analysis of Seismic Responses of Rock Massif to Explosive Impacts with Using Nonlinear Methods DOI: http://dx.doi.org/10.5772/intechopen.80750

In addition, when using the integrated intensity parameter Sp: (<sup>S</sup> <sup>~</sup> <sup>p</sup> <sup>¼</sup> <sup>∑</sup><sup>i</sup> <sup>M</sup>0ðx; <sup>H</sup>Þ, where <sup>H</sup> is the investigated thickness of the massif in the bottom of the hole, the x-coordinate of the center of the zone along the generation, and i is the number of the zone), there is good convergence with seismic monitoring data of the same research area and the active electromagnetic monitoring. Therefore, to construct the phase portrait of the state of the array at various horizons and in the excavations located at various distances from the clearing space, we use as parameters the parameters Spint and d/dt (Spint), as well as Sp and d/dt (Sp) defined for seven cycles of active electromagnetic induction monitoring. By the symbols d/dt (Spint) and d/dt (Sp), we mean the difference of consecutive (in time) values; the time interval is 1 year. By a phase trajectory, we mean a discrete set of points in the phase plane defined by phase coordinates in a given time sequence corresponding to the observation cycles. All phase trajectories can be divided into three groups according to the occupied area in the phase plane and the position on the phase plane of the center of gravity of the figure described by this trajectory. By the area occupied by the phase trajectory on the phase plane, we mean the exact lower bound of the set of areas of convex polygons containing a given phase trajectory. The center of gravity of the constructed figure may turn out to be a point of attraction; however, due to the lack of data, this point will be called the center of gravity of the figure described by the phase trajectory. The three groups identified by the new criteria completely coincide with the earlier classification by the parameter Spint: stable arrays (mountains �210, ort 4) the smallest area of the figure described by the phase trajectory, quasi-stable (mountains �210, ort 2), (mountains. �350, ort 18) is an intermediate in size area occupied by phase trajectories and unstable (mountain �350, ort 19) is the maximum area occupied by the phase trajectory. Thus, in [37] the thesis that the rock mass is an open dynamic system, the state of which is determined by synergetic properties, was demonstrated quantitatively by analyzing phase portraits using phase coordinates in the form of parameters of the integral and the interval intensity of the heterogeneity zones of the second rank and their difference analogs of time derivatives, determined from the data of active electromagnetic induction spatial–temporal discrete monitoring. To date, the question of the topological equivalence of the constructed phase trajectories, following the definition given above, remains open. Investigating this issue will be possible with an increase in the number of phase data.
