WO2015002557A2 - Method and system for measuring relative changes in stress concentration in front of a longwall - Google Patents

Method and system for measuring relative changes in stress concentration in front of a longwall Download PDF

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Publication number
WO2015002557A2
WO2015002557A2 PCT/PL2014/000124 PL2014000124W WO2015002557A2 WO 2015002557 A2 WO2015002557 A2 WO 2015002557A2 PL 2014000124 W PL2014000124 W PL 2014000124W WO 2015002557 A2 WO2015002557 A2 WO 2015002557A2
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WO
WIPO (PCT)
Prior art keywords
longwall
tomography
attenuation
shearer
seismic
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PCT/PL2014/000124
Other languages
French (fr)
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WO2015002557A3 (en
Inventor
Zbigniew ISAKOW
Marek DWORAK
Adam GOŁĄBEK
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Instytut Technik Innowacyjnych Emag
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Application filed by Instytut Technik Innowacyjnych Emag filed Critical Instytut Technik Innowacyjnych Emag
Priority to CN201480002445.1A priority Critical patent/CN105765409B/en
Priority to UAA201501086A priority patent/UA118088C2/en
Priority to RU2015101765/03A priority patent/RU2604532C2/en
Publication of WO2015002557A2 publication Critical patent/WO2015002557A2/en
Publication of WO2015002557A3 publication Critical patent/WO2015002557A3/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/003—Seismic data acquisition in general, e.g. survey design
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/28—Processing seismic data, e.g. for interpretation or for event detection
    • G01V1/30—Analysis
    • G01V1/306—Analysis for determining physical properties of the subsurface, e.g. impedance, porosity or attenuation profiles
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21C—MINING OR QUARRYING
    • E21C39/00—Devices for testing in situ the hardness or other properties of minerals, e.g. for giving information as to the selection of suitable mining tools
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/28—Processing seismic data, e.g. for interpretation or for event detection
    • G01V1/30—Analysis
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/28—Processing seismic data, e.g. for interpretation or for event detection
    • G01V1/30—Analysis
    • G01V1/303—Analysis for determining velocity profiles or travel times
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V2210/00—Details of seismic processing or analysis
    • G01V2210/10—Aspects of acoustic signal generation or detection
    • G01V2210/12—Signal generation
    • G01V2210/123—Passive source, e.g. microseismics
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V2210/00—Details of seismic processing or analysis
    • G01V2210/10—Aspects of acoustic signal generation or detection
    • G01V2210/12—Signal generation
    • G01V2210/123—Passive source, e.g. microseismics
    • G01V2210/1236—Acoustic daylight, e.g. cultural noise
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V2210/00—Details of seismic processing or analysis
    • G01V2210/60—Analysis
    • G01V2210/61—Analysis by combining or comparing a seismic data set with other data
    • G01V2210/612—Previously recorded data, e.g. time-lapse or 4D
    • G01V2210/6122—Tracking reservoir changes over time, e.g. due to production
    • G01V2210/6124—Subsidence, i.e. upwards or downwards
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V2210/00—Details of seismic processing or analysis
    • G01V2210/60—Analysis
    • G01V2210/62—Physical property of subsurface
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V2210/00—Details of seismic processing or analysis
    • G01V2210/60—Analysis
    • G01V2210/62—Physical property of subsurface
    • G01V2210/622—Velocity, density or impedance
    • G01V2210/6222—Velocity; travel time

Definitions

  • Proposed invention relates to a method and a system for measuring relative changes in stress concentration in front of a longwall for detecting and monitoring a rock burst hazard in the longwall region of a deep mine.
  • Polish patent PL207323 (B1) discloses a method, which uses a standard longwall network of seismoacoustic geophones installed in the longwall galleries in front of the longwall, in known distances from an intersection with that wall. Value of absorption coefficient is determined on a basis of cumulated energy of seismoacoustic events recorded by these geophones at fixed time intervals, preferably including one full cut of the wall. The distance of the geophones from said intersection is presumed to be their distance from the source of seismoacoustic impulses. Effective attenuation coefficient is calculated according to known physical equations relating observed wave energy to the distances from the source, and to the absorption factor.
  • Another Polish patent PL202149 (B1) describes a system for continuous monitoring of the stress relative changes in the rock mass in front of the longwall.
  • the system is characterized in that the transmitters equipped with geophones installed, respectively, in the roof and in the side wall or the bed of the mine working are connected via transmission lines to the interfaces of the recording computer.
  • the transmitters are powered from these lines with intrinsically safe current.
  • For estimation of a state of relative stress one uses vibrations produced by the cutting head of the shearer, by determination of vibrations damping isolines in the controlled bed or roof.
  • the computer performs calculations of size and distribution of relative changes in seismic wave attenuation which are approximately inversely proportional to relative changes in stress. This allows to present them in the form of tomographic maps containing isolines of relative changes in stress.
  • a system of multi-channel portable seismic equipment known from Polish patent PL152339 (B1 ) is designed to control the state of the rock mass in the area of mine workings, to determine the stress distribution in time and space and to identify the heterogeneity of the deposit by the active seismic velocity tomography.
  • the system consists of a microprocessor block of internal static random access memory RAM and programmable memory EPROM, which is connected via a cumulative system bus to the block of extended RAM memory with battery backup, real-time clock, control module actuated by an inertia relay, and a block controlling both the measurements and the multi-channel analog input block, to which the geophones are connected.
  • the analog measurements control block and the block of analog inputs are connected through internal bus.
  • the control unit with LCD indicator and serial transmission block with two-way serial output are attached to the bus system.
  • Chinese patent documents CN 101762830 (B) and CN 102279410 (A) disclose integrated systems and methods for monitoring the rock mass through a network of seismic and seismoacoustic sensors connected to the base computer via Ethernet, which are used to analyze the signals recorded in a spatial distribution, and for location of the seismic burst source in the monitored mine workings.
  • Russian patent application RU201 1 1 12877 discloses a method of monitoring of the state of stress and deformation of the rock mass in course of mining works.
  • the process of measuring the characteristics of the elastic waves field in the rock mass is performed continuously along the three coordinate axes, using 3-axis vibration sensors recording changes in the parameters of the wave field and quantitative changes in the state of stress and deformation, according to data from direct and reflected waves of different polarization.
  • the 3-axis vibration sensors are arranged at two sides along development workings, i.e. where monitoring of the state of stress and deformation is performed. Vibrations generated by the cutting head of the shearer are the source of elastic waves.
  • the apparatus is composed of the measurement and transmission modules MPT connected through the shielded cable for analog data transmission of two geophone probes consisting of three geophones oriented in a 3-dimensional space.
  • the MPT modules are equipped with the microcontrollers with the FRAM memory, precise instrumentation amplifiers with variable gain, 24-bit compensating converters with anti-aliasing filter, and transmission systems CAN.
  • Each module is powered from built-in intrinsically safe battery.
  • the MWP module controls configuration and transmission of signals from the MPT modules. It is also powered by its own battery. It has a triggering input, allowing for start of measurements at the micro-blast ignition or at mechanical initiation by a hammer stroke.
  • the PDA module has a Bluetooth interface for communication with the PDA module, which includes software for configuration of the measurement session, i.e. measurement times, frequencies, gain, and measurement data acquisition. These data are also transmitted via Bluetooth interface to a PC computer installed on the mine surface for further processing.
  • the principle of measurement is excitation of seismic wave with simultaneous generation of the triggering signal by the current loop closing or opening.
  • the signal received by the MWP module allows for synchronization of all MPT modules. Since then, the seismic wave registration begins.
  • the measurement data are stored in the PDA module.
  • Specialized software generates seismograms based on recorded data. From these seismograms one can determine the times of occurrence of particular type of waves, their amplitude, frequency, calculate e.g. velocity or acceleration of the medium vibrations. Building of the apparatus and measurements are performed in seismic silence, which requires a break in the longwall mining for at least one mine shift. Discussion of the prior art
  • the aim of the invention is to provide a method and a system implementing measurement of relative changes in stress present in the coal bed in front of the longwall in a deep mine. This will enable ongoing and free of dead zones measurement of the stress changes in course of the longwall mining with simultaneously broadened range of identification of the state of stress concentration and increased accuracy and reliability of measurement of relative changes in stress to ensure a prompt and more effective rock bursts prevention.
  • the capture-control server records the vibration signals from the 3-axis geophones installed in the longwall galleries, synchronously in all measuring channels and in synchronized time intervals, and in close correlation with signals informing about the shearer location and operation mode in a wall working.
  • the capture-control server localizes seismic phenomena, and after finishing each cut by the shearer it analyzes relative changes in stress in the body of coal in front of the longwall with use of the attenuation-damping tomography, using registered energy of a wave induced by the mining device.
  • the capture-control server proceeds with the velocity or attenuation active tomography of the rock mass between the galleries with seismic waves triggered remotely from the mine surface by the server through the exciter of vibrations.
  • the server analyzes the stress by a method of velocity and / or attenuation passive tomography with use of tremors induced by mining as a source of the shock wave.
  • an averaged cumulated tomographic map of concentration of relative changes in the stress is drawn and / or the maps are drawn up of particular tomographies.
  • the stress analysis using active tomography of the rock mass between the galleries using a seismic wave caused by the exciters of vibrations is performed automatically in a state after the cutting head has ended its work.
  • the shearer resumes working when the tomography is performed, the latter is interrupted until next break in the shearer working is detected.
  • Sampling of signals from the 3-axis geophones and analog-to-digital conversion is synchronous with the clock reference tact with the sampling frequency, and preferably with simultaneous compensation of delays caused by different lengths of the transmission lines.
  • internal time of the measurement data local hub is synchronized with use of IEEE 1588 PTP protocol, with the satellite global positioning module GPS via the capture-control server.
  • the resultant averaged cumulated tomographic map of concentration of relative changes in stress and / or the maps of particular tomographies are visualized on the cumulated tomography visualization panel and on the active attenuation- damping tomography visualization panel, on the active velocity and / or attenuation tomography visualization panel and on the passive velocity and / or attenuation visualization panel.
  • the pulse exciters are triggered remotely by bringing compressed medium from its source into a space over the piston of the pulse exciter.
  • the compressed medium is provided by opening of the electropneumatic distributor initiated by an impulse from the capture-control server located on the mine surface via the transmitter module and the digital receiver. Accordingly to the longwall progress the initiation and vibration measurement modules are arranged in the side walls of the galleries and attached to the pre-installed anchors.
  • a system for measuring relative changes in stress concentration in the longwall face is composed of at least six universal initiation and vibration measurement modules arranged in one of the longwall galleries and at least six vibration measurement modules arranged in the opposite longwall gallery, or of at least twelve universal initiation and vibration measurement modules installed symmetrically, i.e. six in each of two longwall galleries. They are connected by the intrinsically safe digital transmission lines to a local measurement data concentrator which is connected to the intrinsically safe power buffer supply, and via the optical Ethernet network to the capture-control server.
  • the capture-control server is connected to the mine dispatching system, the global positioning satellite module, the internal time module, and the processing server, which is connected to the cumulated tomography visualization panel, and preferably to the active attenuation-damping tomography visualization panel, the active velocity and / or attenuation tomography visualization panel, and the passive tomography visualization panel.
  • the mine dispatching system is connected to the shearer through the position and operation control system of the shearer, which is equipped with the position sensor.
  • the universal initiation and vibration measurement module is equipped with the pulse vibration exciter and the 3-axis measuring probe, and is mechanically attached to the anchors embedded in the side wall, roof or the floor of the wall working.
  • the 3-axis geophone is connected to the transmitter module and the digital receiver.
  • the pulse vibration exciter is equipped with the electropneumatic distributor with the control unit coupled to the transmitter and digital receiver module.
  • the outlet of the electropneumatic distributor is connected to the space over the piston of the blast element of the pulse vibration exciter equipped with a supra-piston compression spring.
  • the inlet of the electropneumatic distributor is connected by a conduit to the local supply module which is a source of pneumatic medium, most preferably compressed nitrogen.
  • the vibration measurement module consists of the 3-axis measuring probe mechanically attached to the anchor embedded in the side wall, roof, or the floor of the wall working.
  • the 3-axis geophone is connected to the transmitter and digital receiver module.
  • the present invention is based on three methods of seismic-wave tomography.
  • First method is the active velocity or attenuation tomography involving seismic scanning of the body of coal between the galleries with seismic wave FS artificially induced in the mine underground part E by an impulse controlled from the mine surface D with use of the pulse vibration exciters 18.
  • Second simultaneously used method is the active attenuation-damping tomography using seismic scanning of the longwall area with seismic wave FK induced by the mining head of the shearer 15 with simultaneous correlation of these measurements with signals informing about operation and position of the shearer 15 in the wall working B.
  • Third method of passive velocity or attenuation tomography uses tremors induced by mining as a source of seismic wave FP.
  • new universal initiation and vibration measurement modules 1 deployed in the side walls of the longwall galleries A and attached to the pre- installed anchors 20 and their movements with the longwall progress allows for free and appropriate measurements programming, and remote controlling of measurements with use of active seismic tomography, using scanning of the rock mass between the galleries A by artificially induced seismic waves FS.
  • the method and system according to the invention performs current measurements during normal operation of the longwall system and allows for continuous monitoring of changes in stress concentration, which is essential for safety of the mining crews, because it allows for rapid evacuation of the crew in case of the rock burst hazard and allows for use of preventive reduction of the rock burst hazards.
  • Fig. 1 - shows a block diagram of the measuring system with universal initiation and measurement modules in both of the longwall galleries
  • Fig.2 - shows a block diagram of a universal initiation and vibration measurement module
  • Fig. 3 - shows a block diagram of the measurement system with universal initiation and measurement modules arranged in one of the longwall galleries
  • Fig. 4 - shows a block diagram of the vibrations measurement module.
  • Invented method is based on current measurements and analysis with use of a new cumulated seismic tomography applying the active velocity or attenuation tomography and active attenuation-damping tomography using for this purpose the mechanical impulse vibration exciters 18 controlled from the mine surface and firing artificial seismic wave FS, and complementary attenuation-damping tomography involving analysis of seismic waves FK excited by the mining head of the shearer 15, whose position relative to the longwall is recorded by the system of the shearer position and operation control 17.
  • the changes in stress are recognized with the method of passive tomography using shocks W1 , W2 ... Wi localized by the processing server 10 in the area of controlled longwall as the sources of scanning waves.
  • the initiation and vibration measurement modules 1 are arranged in the side walls of both longwall galleries A or, depending on current needs, in only one of the longwall galleries A, while in the opposite longwall gallery A the vibration measurement modules 28 are distributed.
  • the initiation and vibration measurement modules 1 and the vibration measurement modules 28 are moved according to the longwall progress.
  • the analysis of relative changes in stress with a method of active tomography by the rock mass scanning between the longwall galleries A using the seismic wave induced by the vibration exciters 18 is performed automatically in a state when the longwall shearer 15 has completed a cut, and the mining part ended its work. If the longwall shearer 5 resumes mining during active tomography using vibration exciters 18, the measuring procedure is suspended until detection of next stop of the shearer 15.
  • Seismic waves FK generated by the mining head of the shearer 15 repeatedly scan the body of coal C in front of the longwall and allow for attenuation-damping tomography of this area.
  • the dead zone SX occurring in this method in the form of a triangle, in which the seismic rays cannot scan the floor or the roof away from the longwall front, is analyzed by supplementary measurements of active velocity or attenuation tomography, in which the seismic waves FS generated in the longwall galleries A and triggered by the pulse vibration exciters 18 controlled from the mine surface are analyzed.
  • Sampling of signals from the 3-axis geophones 9 and conversion of analog signal to digital signal by the module 21 are performed synchronously with the tact reference clock signal with sampling frequency of preferably 10 kHz.
  • the capture-control server 6 sends these data to the processing server 10, which analyzes recorded data, calculates and visualizes the maps of active attenuation-damping tomography on the active attenuation-damping tomography visualization panel 1 1 , the maps of active velocity or attenuation tomography on the active velocity or attenuation tomography visualization panel 12, the maps of passive tomography on the passive velocity or attenuation tomography visualization panel 13, and the maps of cumulated tomography on the cumulated tomography visualization panel 14.
  • Each universal initiation and vibration measurement module 1 shown on Fig. 2 is attached to the anchor 20 firmly embedded in the rock mass, i.e. in the side wall, the roof or the floor of the gallery.
  • the initialization and vibration measurement module 1 includes pulse vibration exciter 18 integrated with the 3-axis geophone 19.
  • the analog output signals are transmitted to the input of the transmitter and digital receiver module 21. In digital form via the intrinsically safe transmission digital line 2 they are transmitted to the local measurement data hub 3 and further via the optical Ethernet network 5 to the capture-control server 6.
  • the transmitter receiver module 21 receives and transmits the signal 27 for actuating the electro-distributor 22, which is sent by the processing server 10 to cause periodically a single actuation of the vibration exciters 18 initiating artificially induced seismic waves FS.
  • Activation of the vibration exciters 18 is realized by providing to the space over the piston of the blast element 23 of the pulse vibration exciter 18 of a medium 25 quantity pressurized in a fluid supply source 26, which causes the hammer element 23 to hit the anchor 20.
  • the moment of generation of the artificially induced seismic wave FS by the pulse vibration exciter 18, is identified by the 3-axis geophone 19.
  • a bottle of compressed nitrogen which is the pneumatic medium supply module 26 is exchanged periodically after the system pressure falls below the permissible value.
  • Inappropriate activation of the pulse vibration exciter 18 is identified by the 3-axis geophone 19 recording vibrations at the time of their excitation.
  • the system according to the invention shown schematically in Fig. 1 consists of sixteen universal initiation vibration measurement modules 1 disposed symmetrically every 15 meters in the longwall galleries A longer than 120 m.
  • Universal initiation and vibration measurement modules 1 are connected by the intrinsically safe digital transmission lines 2 to local measurement data hub 3 which is connected to the intrinsically safe power buffer supply 4, and via the optical Ethernet network 5 to the capture-control server 6 located on the surface of the mine D.
  • the capture-control server 6 is connected to the mine dispatcher system 7, the global satellite positioning module 8, the internal time module 9, and processing server 10.
  • the mine dispatching system 7 is connected to the shearer 15, which is equipped with, among others, the shearer position sensor 16 transmitting position data of the shearer to the shearer position and the operation control system 17 which is one of the components of the mine dispatching system 7.
  • Each of the universal initiation and vibration measuring modules 1 (Fig. 2) is provided with the pulse vibration exciter 18 and the 3-axis geophone 19, and is mechanically attached to the anchors 20, embedded in the side walls or in the floor or the roof of the longwall galleries A, depending on the needs.
  • the 3-axis geophone 19 is connected to the transmitter and receiver digital module 21 whose input and output of digital transmission is connected via intrinsically safe digital transmission supply line 2 to digital receiver of that channel of local measurement data concentrator 3 powered by the intrinsically safe power buffer supply 4.
  • the pulse vibration exciter 18 is equipped with the electro-pneumatic distributor 22, the control unit of which is coupled to the transmitter and receiver digital module 2 .
  • Compressed nitrogen is fed from the outlet of the electro-pneumatic distributor 22 to the space over the piston of the impact element 23 of the pulse vibration exciter 18 equipped with the supra- piston compression spring 24.
  • Pneumatic medium 25 from the supplying unit 26 in the form of compressed nitrogen stored in a portable pressure bottle with a regulator is fed to the inlet of the electro-pneumatic distributor 22 by a supplying conduit.
  • FIG. 3 Another embodiment of the invention is shown in Fig. 3 and it consists of at least six universal initiation and vibration measuring modules 1 arranged for in one of the longwall galleries A, and at least six vibration measurement modules 28 positioned in the opposite longwall gallery A.
  • Universal initiation and vibration measurement modules 1 and the vibration measurement modules 28 are connected in the same system configuration as described above in the Example II.
  • the vibration measuring module 28 (Fig. 4) consists of the 3-axis geophone 19 attached mechanically to the anchor 20 embedded depending on the needs in the side wall, the floor or the roof of the longwall gallery A.
  • the 3-axis geophone 19 is connected to the transmitter and receiver digital module 21.

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Abstract

A method for measuring relative changes in stress in front of a longwall is characterized in that the capture-control server (6) records the vibration measurement signals from the 3-axis geophones (19) installed in the longwall galleries (A), spatially oriented synchronously in all channels and in synchronized time interval, and in close correlation with the signals informing about the operation and position of the shearer (15) in the working (B) and on this basis, in cooperation with the processing server (10) it localizes the seismic phenomena. After ending of each cut by the shearer (15) it analyzes relative changes in stress in the body of coal (C) in front of the longwall with attenuation-damping tomography involving analysis of seismic waves (FK). After ending of the cut during the shearer (15) standstill, it makes the active velocity or attenuation tomography by seismic imaging of the rock mass between the longwall galleries (A) using seismic waves (FS), and then analyzes the stress with passive velocity and / or attenuation tomography using seismic waves (FP). Then periodically, preferably several times during one mining shift the averaged cumulated tomographic maps of relative changes in stress, and / or the maps of particular tomographies are drawn. The system comprises at least six universal initiation and vibration measurement modules (1) arranged in each of the longwall galleries (A), which are connected via intrinsically safe digital transmission lines (2) to a local measurement data concentrator (3), which is connected to an intrinsically safe power buffer supply (4) and via the optical Ethernet network (5) to the capture-control server (6) connected to the mine dispatching system (7), the global satellite positioning module (8), the internal time module (9) and the processing server (10). The processing server (10) is connected to the cumulated tomography visualization panel (14) and preferably to the active attenuation-damping tomography visualization panel (11), the active velocity or attenuation tomography visualization panel (12), and the passive velocity or attenuation tomography visualization panel (13).

Description

Method and system for measuring relative changes in stress concentration in front of a longwall
Proposed invention relates to a method and a system for measuring relative changes in stress concentration in front of a longwall for detecting and monitoring a rock burst hazard in the longwall region of a deep mine.
The state of the art
Polish patent PL207323 (B1) discloses a method, which uses a standard longwall network of seismoacoustic geophones installed in the longwall galleries in front of the longwall, in known distances from an intersection with that wall. Value of absorption coefficient is determined on a basis of cumulated energy of seismoacoustic events recorded by these geophones at fixed time intervals, preferably including one full cut of the wall. The distance of the geophones from said intersection is presumed to be their distance from the source of seismoacoustic impulses. Effective attenuation coefficient is calculated according to known physical equations relating observed wave energy to the distances from the source, and to the absorption factor.
Another Polish patent PL202149 (B1) describes a system for continuous monitoring of the stress relative changes in the rock mass in front of the longwall. The system is characterized in that the transmitters equipped with geophones installed, respectively, in the roof and in the side wall or the bed of the mine working are connected via transmission lines to the interfaces of the recording computer. The transmitters are powered from these lines with intrinsically safe current. For estimation of a state of relative stress one uses vibrations produced by the cutting head of the shearer, by determination of vibrations damping isolines in the controlled bed or roof. The computer performs calculations of size and distribution of relative changes in seismic wave attenuation which are approximately inversely proportional to relative changes in stress. This allows to present them in the form of tomographic maps containing isolines of relative changes in stress.
A system of multi-channel portable seismic equipment known from Polish patent PL152339 (B1 ) is designed to control the state of the rock mass in the area of mine workings, to determine the stress distribution in time and space and to identify the heterogeneity of the deposit by the active seismic velocity tomography. The system consists of a microprocessor block of internal static random access memory RAM and programmable memory EPROM, which is connected via a cumulative system bus to the block of extended RAM memory with battery backup, real-time clock, control module actuated by an inertia relay, and a block controlling both the measurements and the multi-channel analog input block, to which the geophones are connected. The analog measurements control block and the block of analog inputs are connected through internal bus. The control unit with LCD indicator and serial transmission block with two-way serial output are attached to the bus system.
The methods of seismic imaging using active seismic-wave tomography and passive seismic-wave tomography are known from the publication "Methods for evaluation of rockburst hazards of the mine workings in the coal mines" (2010.), Jozef Kabiesz, ed., Central Mining Institute in Katowice, pp.165-320.
Chinese patent documents CN 101762830 (B) and CN 102279410 (A) disclose integrated systems and methods for monitoring the rock mass through a network of seismic and seismoacoustic sensors connected to the base computer via Ethernet, which are used to analyze the signals recorded in a spatial distribution, and for location of the seismic burst source in the monitored mine workings.
In another Chinese patent document CN101581789 (A) a method of detection of disturbances in the rock mass of a mine is described. This method consists of seismoscopic imaging of the rock mass between the longwall galleries with use of active tomography method. This method uses the 3-axis (3D) geophones placed along the longwall galleries, and a detonation of explosive charge in the opposite gallery is a source of elastic waves. The method consists of registration of distribution of elastic waves induced at points of blasting in a coal bed by the 3-axis geophones. Geological anomalies in the rock mass are determined on the basis of the analysis of these measurements.
Russian patent application RU201 1 1 12877 (A) discloses a method of monitoring of the state of stress and deformation of the rock mass in course of mining works. The process of measuring the characteristics of the elastic waves field in the rock mass is performed continuously along the three coordinate axes, using 3-axis vibration sensors recording changes in the parameters of the wave field and quantitative changes in the state of stress and deformation, according to data from direct and reflected waves of different polarization. During mining works the 3-axis vibration sensors are arranged at two sides along development workings, i.e. where monitoring of the state of stress and deformation is performed. Vibrations generated by the cutting head of the shearer are the source of elastic waves. In the process of measuring the characteristics of elastic waves in the rock mass, the method of seismic tomography is used to locate stress in the body of coal along the panel length of the mined longwall. Other patent applications EP1085347 (A2), EP0333363 (A2), and RU201 1 142893 (A), deal with an equipment for artificial excitation of seismic waves for seismic-wave tomography of the rock mass. In these devices kinetic energy of mechanical impact elements is released by a pneumatic medium.
The publication of K.Oset, Z.lsakow and S.Trenczek, "Recognition of the state of the rock mass using modern measuring equipment PASAT M" (Proceedings of the XVth Jubilee International Geotechnical Symposium "Geotechnics 2012", Materiafy Naukowe, Gliwice - Ustroii, 23-26 October, 2012) describes intrinsically safe portable seismic equipment designed for seismic screening between the workings and between the holes, for longitudinal seismic profiling in the headings, and for seismic probing and testing of the rock mass to occurrence of latent reservoirs of methane and other gases. The apparatus is designed for periodically performed seismic measurements with use of the active seismic-wave tomography method. This allows to determine the extent of areas endangered with the earth tremors through screening of the rock mass with artificial seismic wave. The apparatus is composed of the measurement and transmission modules MPT connected through the shielded cable for analog data transmission of two geophone probes consisting of three geophones oriented in a 3-dimensional space. The MPT modules are equipped with the microcontrollers with the FRAM memory, precise instrumentation amplifiers with variable gain, 24-bit compensating converters with anti-aliasing filter, and transmission systems CAN. Each module is powered from built-in intrinsically safe battery. The MWP module controls configuration and transmission of signals from the MPT modules. It is also powered by its own battery. It has a triggering input, allowing for start of measurements at the micro-blast ignition or at mechanical initiation by a hammer stroke. Additionally, it has a Bluetooth interface for communication with the PDA module, which includes software for configuration of the measurement session, i.e. measurement times, frequencies, gain, and measurement data acquisition. These data are also transmitted via Bluetooth interface to a PC computer installed on the mine surface for further processing. The principle of measurement is excitation of seismic wave with simultaneous generation of the triggering signal by the current loop closing or opening. The signal received by the MWP module allows for synchronization of all MPT modules. Since then, the seismic wave registration begins. The measurement data are stored in the PDA module. Specialized software generates seismograms based on recorded data. From these seismograms one can determine the times of occurrence of particular type of waves, their amplitude, frequency, calculate e.g. velocity or acceleration of the medium vibrations. Building of the apparatus and measurements are performed in seismic silence, which requires a break in the longwall mining for at least one mine shift. Discussion of the prior art
Hitherto performed ad hoc measurements in seismic-wave tomography in large time intervals do not allow for ongoing monitoring of the state of stress changes in front of the longwall and further evaluation of effectiveness of the stress preventive relieving. The main operational drawback of known intrinsically safe portable seismic appliances is a necessity to make measurements in seismic silence, which requires to stop working the longwall for at least one mining shift in order to install the sensors, connect the components of the measurement system and make measurements using seismic wave generated by a hammer or small amount of explosives. This is not always possible and requires continuous monitoring of methane concentration.
However, from the point of view of measurement quality and reliability, the main drawback of individual velocity active seismic tomography implemented with use of known portable seismic appliances is appearance of the "dead zones" where information about the rock stress is incomplete. The first one is a dead zone SY for seismic rays in the longwall heading, because usually the blowing charges are not fired there. In turn, credibility of individually applied passive tomography depends on the number and distribution of localized seismic events in the wall. Again, individual implementation of the attenuation-damping tomography realized with use of the shearer mining head as a source of seismic wave does not give information about the stress concentration inside the body of coal in front of the longwall, because of formation of another dead zone SX. When the sensors are distributed in the longwall galleries, this zone is not imaged by seismic waves.
Aim of the invention
The aim of the invention is to provide a method and a system implementing measurement of relative changes in stress present in the coal bed in front of the longwall in a deep mine. This will enable ongoing and free of dead zones measurement of the stress changes in course of the longwall mining with simultaneously broadened range of identification of the state of stress concentration and increased accuracy and reliability of measurement of relative changes in stress to ensure a prompt and more effective rock bursts prevention. Summary of the invention
In proposed new method of measurement of relative changes in stress in front of the longwall, the capture-control server records the vibration signals from the 3-axis geophones installed in the longwall galleries, synchronously in all measuring channels and in synchronized time intervals, and in close correlation with signals informing about the shearer location and operation mode in a wall working. On this basis, in cooperation with the processing server the capture-control server localizes seismic phenomena, and after finishing each cut by the shearer it analyzes relative changes in stress in the body of coal in front of the longwall with use of the attenuation-damping tomography, using registered energy of a wave induced by the mining device.
During the shearer standstill the capture-control server proceeds with the velocity or attenuation active tomography of the rock mass between the galleries with seismic waves triggered remotely from the mine surface by the server through the exciter of vibrations. Next, the server analyzes the stress by a method of velocity and / or attenuation passive tomography with use of tremors induced by mining as a source of the shock wave. Then periodically, preferably several tinies during one mine shift, an averaged cumulated tomographic map of concentration of relative changes in the stress is drawn and / or the maps are drawn up of particular tomographies. Finally the stress analysis using active tomography of the rock mass between the galleries using a seismic wave caused by the exciters of vibrations is performed automatically in a state after the cutting head has ended its work.
If the shearer resumes working when the tomography is performed, the latter is interrupted until next break in the shearer working is detected. Sampling of signals from the 3-axis geophones and analog-to-digital conversion is synchronous with the clock reference tact with the sampling frequency, and preferably with simultaneous compensation of delays caused by different lengths of the transmission lines. Most preferably, internal time of the measurement data local hub is synchronized with use of IEEE 1588 PTP protocol, with the satellite global positioning module GPS via the capture-control server.
Further, the resultant averaged cumulated tomographic map of concentration of relative changes in stress and / or the maps of particular tomographies are visualized on the cumulated tomography visualization panel and on the active attenuation- damping tomography visualization panel, on the active velocity and / or attenuation tomography visualization panel and on the passive velocity and / or attenuation visualization panel.
The pulse exciters are triggered remotely by bringing compressed medium from its source into a space over the piston of the pulse exciter. The compressed medium is provided by opening of the electropneumatic distributor initiated by an impulse from the capture-control server located on the mine surface via the transmitter module and the digital receiver. Accordingly to the longwall progress the initiation and vibration measurement modules are arranged in the side walls of the galleries and attached to the pre-installed anchors.
A system for measuring relative changes in stress concentration in the longwall face is composed of at least six universal initiation and vibration measurement modules arranged in one of the longwall galleries and at least six vibration measurement modules arranged in the opposite longwall gallery, or of at least twelve universal initiation and vibration measurement modules installed symmetrically, i.e. six in each of two longwall galleries. They are connected by the intrinsically safe digital transmission lines to a local measurement data concentrator which is connected to the intrinsically safe power buffer supply, and via the optical Ethernet network to the capture-control server. The capture-control server is connected to the mine dispatching system, the global positioning satellite module, the internal time module, and the processing server, which is connected to the cumulated tomography visualization panel, and preferably to the active attenuation-damping tomography visualization panel, the active velocity and / or attenuation tomography visualization panel, and the passive tomography visualization panel.
The mine dispatching system is connected to the shearer through the position and operation control system of the shearer, which is equipped with the position sensor. The universal initiation and vibration measurement module is equipped with the pulse vibration exciter and the 3-axis measuring probe, and is mechanically attached to the anchors embedded in the side wall, roof or the floor of the wall working. The 3-axis geophone is connected to the transmitter module and the digital receiver. The pulse vibration exciter is equipped with the electropneumatic distributor with the control unit coupled to the transmitter and digital receiver module. The outlet of the electropneumatic distributor is connected to the space over the piston of the blast element of the pulse vibration exciter equipped with a supra-piston compression spring. The inlet of the electropneumatic distributor is connected by a conduit to the local supply module which is a source of pneumatic medium, most preferably compressed nitrogen. The vibration measurement module consists of the 3-axis measuring probe mechanically attached to the anchor embedded in the side wall, roof, or the floor of the wall working. The 3-axis geophone is connected to the transmitter and digital receiver module. Effects of the invention
The present invention is based on three methods of seismic-wave tomography. First method is the active velocity or attenuation tomography involving seismic scanning of the body of coal between the galleries with seismic wave FS artificially induced in the mine underground part E by an impulse controlled from the mine surface D with use of the pulse vibration exciters 18. Second simultaneously used method is the active attenuation-damping tomography using seismic scanning of the longwall area with seismic wave FK induced by the mining head of the shearer 15 with simultaneous correlation of these measurements with signals informing about operation and position of the shearer 15 in the wall working B. Third method of passive velocity or attenuation tomography uses tremors induced by mining as a source of seismic wave FP.
By using of new comprehensive method for determination of relative changes in velocity and attenuation of seismic waves, and indirectly of relative changes in stress concentration in front of the longwall which are approximately directly proportional to velocity and inversely proportional to attenuation, resultant averaged cumulated tomographic maps of relative changes in stress are drawn several times during each mining shift, without necessity to stop the longwall mining, and with elimination of restrictions resulting from each of these methods taken alone. The invention enables current observation of changes in seismic wave velocity, which is an image of places of concentration of the stress increase, by registration of the speed increase or destruction of the rock mass in the zones with reduced speed of seismic wave. It also eliminates, present in the method of scanning the wall area with the wave generated by the mining head of the shearer 15, the dead zone SX in the form of a triangle by current seismic scanning performed between the longwall galleries A, with use of the pulse vibrations exciters 18 controlled from the mine surface.
Furthermore, the use of new universal initiation and vibration measurement modules 1 deployed in the side walls of the longwall galleries A and attached to the pre- installed anchors 20 and their movements with the longwall progress allows for free and appropriate measurements programming, and remote controlling of measurements with use of active seismic tomography, using scanning of the rock mass between the galleries A by artificially induced seismic waves FS. The method and system according to the invention performs current measurements during normal operation of the longwall system and allows for continuous monitoring of changes in stress concentration, which is essential for safety of the mining crews, because it allows for rapid evacuation of the crew in case of the rock burst hazard and allows for use of preventive reduction of the rock burst hazards.
The invention is shown in an exemplary embodiment in the drawing where Fig. 1 - shows a block diagram of the measuring system with universal initiation and measurement modules in both of the longwall galleries, Fig.2 - shows a block diagram of a universal initiation and vibration measurement module, Fig. 3 - shows a block diagram of the measurement system with universal initiation and measurement modules arranged in one of the longwall galleries, and Fig. 4 - shows a block diagram of the vibrations measurement module.
Example I (method)
Invented method is based on current measurements and analysis with use of a new cumulated seismic tomography applying the active velocity or attenuation tomography and active attenuation-damping tomography using for this purpose the mechanical impulse vibration exciters 18 controlled from the mine surface and firing artificial seismic wave FS, and complementary attenuation-damping tomography involving analysis of seismic waves FK excited by the mining head of the shearer 15, whose position relative to the longwall is recorded by the system of the shearer position and operation control 17. Moreover, the changes in stress are recognized with the method of passive tomography using shocks W1 , W2 ... Wi localized by the processing server 10 in the area of controlled longwall as the sources of scanning waves. Effective use of this method depends on seismic activity and distribution of tremors in the region of monitored longwall. The initiation and vibration measurement modules 1 are arranged in the side walls of both longwall galleries A or, depending on current needs, in only one of the longwall galleries A, while in the opposite longwall gallery A the vibration measurement modules 28 are distributed. The initiation and vibration measurement modules 1 and the vibration measurement modules 28 are moved according to the longwall progress. The analysis of relative changes in stress with a method of active tomography by the rock mass scanning between the longwall galleries A using the seismic wave induced by the vibration exciters 18 is performed automatically in a state when the longwall shearer 15 has completed a cut, and the mining part ended its work. If the longwall shearer 5 resumes mining during active tomography using vibration exciters 18, the measuring procedure is suspended until detection of next stop of the shearer 15.
Seismic waves FK generated by the mining head of the shearer 15 repeatedly scan the body of coal C in front of the longwall and allow for attenuation-damping tomography of this area. The dead zone SX occurring in this method in the form of a triangle, in which the seismic rays cannot scan the floor or the roof away from the longwall front, is analyzed by supplementary measurements of active velocity or attenuation tomography, in which the seismic waves FS generated in the longwall galleries A and triggered by the pulse vibration exciters 18 controlled from the mine surface are analyzed. The dead zone SY specific for use of active pulse velocity or attenuation tomography initiated with artificial seismic wave FS, is complemented by attenuation-damping tomography with seismic wave FK generated by the mining head of the shearer 15. Sampling of signals from the 3-axis geophones 9 and conversion of analog signal to digital signal by the module 21 are performed synchronously with the tact reference clock signal with sampling frequency of preferably 10 kHz.
Internal time of the local measurement data concentrator 3 is synchronized using IEEE 588 PTP protocol by the satellite clock 8 via a capture-control server 6. Digital data from the 3-axis geophones 19 recorded in the recording server 6 as well as continuous recording and selected recordings of tremors are supplemented with the shearer position information sent by the position and operation system of the shearer 17. This system is a part of the mine dispatching system 7. The capture-control server 6 sends these data to the processing server 10, which analyzes recorded data, calculates and visualizes the maps of active attenuation-damping tomography on the active attenuation-damping tomography visualization panel 1 1 , the maps of active velocity or attenuation tomography on the active velocity or attenuation tomography visualization panel 12, the maps of passive tomography on the passive velocity or attenuation tomography visualization panel 13, and the maps of cumulated tomography on the cumulated tomography visualization panel 14.
Each universal initiation and vibration measurement module 1 shown on Fig. 2 is attached to the anchor 20 firmly embedded in the rock mass, i.e. in the side wall, the roof or the floor of the gallery. The initialization and vibration measurement module 1 includes pulse vibration exciter 18 integrated with the 3-axis geophone 19. The analog output signals are transmitted to the input of the transmitter and digital receiver module 21. In digital form via the intrinsically safe transmission digital line 2 they are transmitted to the local measurement data hub 3 and further via the optical Ethernet network 5 to the capture-control server 6. The transmitter receiver module 21 receives and transmits the signal 27 for actuating the electro-distributor 22, which is sent by the processing server 10 to cause periodically a single actuation of the vibration exciters 18 initiating artificially induced seismic waves FS. Activation of the vibration exciters 18 is realized by providing to the space over the piston of the blast element 23 of the pulse vibration exciter 18 of a medium 25 quantity pressurized in a fluid supply source 26, which causes the hammer element 23 to hit the anchor 20. The moment of generation of the artificially induced seismic wave FS by the pulse vibration exciter 18, is identified by the 3-axis geophone 19. A bottle of compressed nitrogen which is the pneumatic medium supply module 26 is exchanged periodically after the system pressure falls below the permissible value. Inappropriate activation of the pulse vibration exciter 18 is identified by the 3-axis geophone 19 recording vibrations at the time of their excitation.
Example II (system)
The system according to the invention shown schematically in Fig. 1 consists of sixteen universal initiation vibration measurement modules 1 disposed symmetrically every 15 meters in the longwall galleries A longer than 120 m. Universal initiation and vibration measurement modules 1 are connected by the intrinsically safe digital transmission lines 2 to local measurement data hub 3 which is connected to the intrinsically safe power buffer supply 4, and via the optical Ethernet network 5 to the capture-control server 6 located on the surface of the mine D. The capture-control server 6 is connected to the mine dispatcher system 7, the global satellite positioning module 8, the internal time module 9, and processing server 10. The latter is connected to the active attenuation-damping tomography visualization panel 1 1 , the active velocity or attenuation tomography visualization panel 12, the passive velocity or attenuation tomography visualization panel 13, and the cumulated tomography visualization panel 14. The mine dispatching system 7 is connected to the shearer 15, which is equipped with, among others, the shearer position sensor 16 transmitting position data of the shearer to the shearer position and the operation control system 17 which is one of the components of the mine dispatching system 7.
Each of the universal initiation and vibration measuring modules 1 (Fig. 2) is provided with the pulse vibration exciter 18 and the 3-axis geophone 19, and is mechanically attached to the anchors 20, embedded in the side walls or in the floor or the roof of the longwall galleries A, depending on the needs. The 3-axis geophone 19 is connected to the transmitter and receiver digital module 21 whose input and output of digital transmission is connected via intrinsically safe digital transmission supply line 2 to digital receiver of that channel of local measurement data concentrator 3 powered by the intrinsically safe power buffer supply 4. The pulse vibration exciter 18 is equipped with the electro-pneumatic distributor 22, the control unit of which is coupled to the transmitter and receiver digital module 2 . Compressed nitrogen is fed from the outlet of the electro-pneumatic distributor 22 to the space over the piston of the impact element 23 of the pulse vibration exciter 18 equipped with the supra- piston compression spring 24. Pneumatic medium 25 from the supplying unit 26 in the form of compressed nitrogen stored in a portable pressure bottle with a regulator is fed to the inlet of the electro-pneumatic distributor 22 by a supplying conduit. Example III (system)
Another embodiment of the invention is shown in Fig. 3 and it consists of at least six universal initiation and vibration measuring modules 1 arranged for in one of the longwall galleries A, and at least six vibration measurement modules 28 positioned in the opposite longwall gallery A. Universal initiation and vibration measurement modules 1 and the vibration measurement modules 28 are connected in the same system configuration as described above in the Example II. The vibration measuring module 28 (Fig. 4) consists of the 3-axis geophone 19 attached mechanically to the anchor 20 embedded depending on the needs in the side wall, the floor or the roof of the longwall gallery A. The 3-axis geophone 19 is connected to the transmitter and receiver digital module 21.

Claims

Claims
A method for measuring relative changes in stress concentration in front of a longwall comprising determination of relative changes in stress concentration in the rock mass with passive and / or active seismic tomography and with use of vibration measurements with the 3-axis geophones installed in the galleries, characterized in that a capture-control server (6) records the vibration measurement signals from the 3-axis geophones (19) installed in the longwall galleries (A), spatially oriented synchronously in all channels and in synchronized time intervals, and in close correlation with the signals informing about operation and position of a shearer (15) in a working (B) and on this basis, in cooperation with a processing server (10) it localizes the seismic phenomena, and after ending of each cut by the shearer (15) it analyzes relative changes in stress in the body of coal (C) in front of the longwall with an attenuation-damping tomography involving analysis of seismic waves (FK) excited by the mining head of the shearer (15), and after ending of the cut during the shearer (15) standstill, it makes an active velocity or attenuation tomography by seismic imaging of the rock mass between the longwall galleries (A) using seismic waves (FS) triggered by the impulse vibration exciters (18) remotely from the mine surface through the processing server (10), then it analyzes the stress with a passive velocity and / or attenuation tomography using as a source of seismic wave (FP) tremors induced by mining, then periodically, preferably several times during one mining shift the averaged cumulated tomographic maps of relative changes in stress are drawn, and preferably the maps of particular tomographies are drawn. The method according to claim 1 , characterized in that the analysis of relative changes in stress with the active tomography by seismic imaging of the rock mass between the longwall galleries (A) with artificially induced seismic wave (FS) triggered by the pulse vibration exciters (18), is performed automatically in a state where the longwall shearer (15) ended the cut and the mining head finished working, and when the longwall shearer (15) resumes mining during the tomography measurement the latter is interrupted until the end of next cut and stop of the shearer ( 5) and tuming-off of its mining head.
The method according to claim 1 or 2, characterized in that sampling of signals from the 3-axis geophones (19) and analog-to-digital conversion are carried out synchronously with the clock reference tact with preset sampling frequency, most preferably, internal time of measurement data local concentrator (3) is synchronized with use of IEEE 1588 PTP protocol, with a satellite global positioning module (8) via a capture-control server (6).
The method according to claim 1 or 2 or 3, characterized in that the resultant averaged cumulated tomographic map of concentration of relative changes in stress and / or the maps of particular tomographies are visualized on a cumulated tomography visualization panel (14), and additionally on an active attenuation-damping tomography visualization panel (11), on an active velocity and / or attenuation tomography visualization panel (12), and on a passive velocity and / or attenuation visualization panel (13).
The method according to any of claims 1 to 4, characterized in that remote activation of the vibration exciters (18) is realized by providing to a space over a piston of a blast element (23) of pressurized medium from a supply module (26) by opening an electro-pneumatic distributor (22) with a signal (27) sent from the processing server (10) located on the surface of the mine, and transmitted through the capture-control server (6) and a transmitter and receiver digital module (21).
The method according to any of claims 1 to 5, characterized in that the universal initiation and vibration measurement modules (1) are arranged according to the needs in the side walls, or in the floor, or in the roof of the longwall galleries (A) and are attached to the pre-mounted anchors (20 ) and are moved according to the progress of the longwall.
A system for measuring relative changes in stress concentration in front of a longwall comprising , the 3-axis geophones installed in the galleries, characterized in that it comprises a capture-control server (6) that records the vibration measurement signals from the 3-axis geophones (19) installed in the longwall galleries (A), a sensor (16) of a shearer (15) operation and position in a working (B), a processing server (10) localizing the seismic phenomena, and the impulse vibration exciters (18) controlled remotely from the mine surface through the processing server ( 0).
The system according to claim 7, characterized in that it has at least six universal initiation and vibration measurement modules (1) arranged in one of the longwall galleries (A) and at least six vibration measurement modules (28) arranged in the opposite longwall gallery (A), or at least twelve universal initiation and vibration measurement modules (1) arranged by six in each of the longwall galleries (A), which are connected via intrinsically safe digital transmission lines (2) to a local measurement data concentrator (3), which is connected to an intrinsically safe power buffer supply (4) and via an optical Ethernet network (5) to the capture-control server (6) connected to a mine dispatching system (7), a global satellite positioning module (8), an internal time module (9) and the processing server (10).
). The system according to claim 8, characterized in that the mine dispatch system (7) is connected via a shearer position and operation control system (17) to the shearer (15), which is equipped with a shearer position sensor (16).
0. The system according to claim 8 or 9, characterized in that the universal module for initiation and measurement of vibrations (1) is provided with the pulse vibration exciter (18) and the 3-axis geophone (19) and is mechanically attached to an anchor (20) embedded in the side wall, in the floor or in the roof of the longwall working (A), and in that the 3-axis geophone (19) is connected to a transmitter and receiver digital module (21).
1. The system according to any of claims 7 to 10, characterized in that the pulse vibration exciter (18) is provided with an electro-pneumatic distributor (22), the control unit of which is coupled to the transmitter and receiver digital module (21) and a space over a piston of an impact element (23) of the pulse vibration exciter (18) is equipped with a supra-piston compression spring (24) and is connected to the outlet of the electro-pneumatic distributor (22), while the inlet of the electro-pneumatic distributor (22) is connected through a conduit (25) to a pneumatic medium supplying unit (26), preferably in the form of compressed nitrogen.
2. The system according to any of claims 7 to 11 , characterized in that it has a vibration measuring module (28) that comprises the 3-axis geophone (19) attached mechanically to the anchor (20) embedded depending on the needs in the side wall, the floor or the roof of the longwall gallery (A), wherein the 3-axis geophone (19) is connected to the transmitter and receiver digital module (21).
13. The system according to any of claims 7 to 12, characterized in that the processing server (10) is connected to the cumulated tomography visualization panel (14) and preferably to the active attenuation-damping tomography visualization panel (11), the active velocity or attenuation tomography visualization panel (12), and the passive velocity or attenuation tomography visualization panel (13).
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