Abstract:
The present invention is a substance displacement device. The device includes a sensing unit which is positioned in a drill hole or otherwise within the substance, such as soil or rock. A measurement device is connected to the sensing unit to measure changes in resistance caused by deformation of the sensing device. A control device connected to the measuring device determines whether the change in resistance exceeds a threshold, and thus activates an alarm. The sensing device preferably includes a fixed resistance device across its terminations to enable the establishing of a baseline resistance. The sensing device may include an electrical element or an optical element. The alarm can be any suitable type of alarm.

Description:
CROSS-REFERENCE TO RELATED CASES  
       [0001]     This applicant claims the benefit of U.S. Provisional Patent Application No. 60/634,497 filed Dec. 8, 2004, which is hereby incorporated by reference herein in its entirety. 
     
    
     BACKGROUND  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to the improvement of event detection capabilities for cable monitoring devices installed in geotechnical materials, utilizing both time domain reflectometry (TDR) and electrical resistance principles.  
       BACKGROUND  
       [0004]     2. Description of Prior Art  
         [0005]     Time Domain Reflectometry, or TDR, is a remote sensing electrical measurement technique that has been used for many years to determine the spatial location and nature of various objects. An early form of TDR, dating from the 1930s, that most people are familiar with is radar. The type of TDR most commonly referred to by the acronym in the industry is coaxial TDR. Coaxial TDR is essentially a “closed circuit radar”. It involves sending an electrical pulse along a coaxial cable and using an oscilloscope to observe the echoes returning back to the input. This technique was reported in the literature in the 1930&#39;s and 40&#39;s for testing telephone coaxial cables. Numerous TDR articles and books have been written on the subject since.  
         [0006]     TDR has been actively investigated by both government and private enterprise for uses in monitoring mining induced displacements in the geologic mass surrounding the mine. US Bureau of Mine research was started in the 1960&#39;s, when TDR was primarily used to locate breaks in electrical power cables. Since then, use of the method has expanded, but has still not reached its full potential in the field.  
         [0007]     If a geologic material is subject to excess stress, whether generated by natural events (excess rainfall, earthquakes, etc), or by human events (excavation) it displaces to equilibrate this excess stress. This will result in discrete displacement (failure along a plane) or distributed displacement within the geologic mass. TDR cable monitoring is generally conducted by placing a TDR capable cable in a drill hole in the geologic mass. Prior to installation, the cable may be crimped to provide reference reflections in the cable at known physical locations in the rock mass. After crimping, the cable is attached to an anchor, lowered down a borehole, and bonded to the surrounding rock with a cement grout. At locations where progressive geologic movement is sufficient to fracture the grout, cable deformation occurs that can be monitored with a TDR cable tester.  
         [0008]     This technique has been tested at Syncrude Canada, amongst others. Syncrude operates an oil sand mine in northern Alberta, Canada. The oil sand is mined by large draglines, which operate adjacent to the edge of a highwall that varies in height from 40 to 60 m. Coaxial cables were installed in vertical holes at three highwall locations in the immediate vicinity (less than 10 m) of slope inclinometers so that a comparison could be made between the two types of instrumentation. The objective of these installations was to assess the ease or difficulty of installation, suitability to field conditions, ease or difficulty of data acquisition, comparison with existing monitoring procedures, and sensitivity of TDR to slope movements.  
         [0009]     In addition to the field study, an extensive laboratory test program was implemented to correlate TDR reflection magnitude with shear deformation of grouted cables.  
         [0010]     It was concluded that TDR represented a promising technology for slope monitoring, but modifications would be required to increase its sensitivity in oil sands and stiff clay soils. Applications in hard rock mining, such as block caving, indicate that block displacement is sufficiently discrete to shear the cable at distinct points, giving a better response than would be expected in stiff clays. In addition, proper selection of the type of cable to be encapsulated, as well as the encapsulation material (stiffer grout, etc.), can be utilized to increase the system sensitivity to displacement.  
         [0011]     Electrical resistance within a cable has been used anecdotally in a somewhat similar fashion as to TDR cable. For the electrical resistance cable monitoring device, loops of varying length of conducting wire are placed in the ground in a borehole, as discussed previously. Being of various lengths, these conductive loops will all extend to differing depths within the borehole. The conductive end of each loop is left extending from the top of the borehole such that an electrical signal can be transmitted through the cable.  
         [0012]     As for the TDR cable, deformation of the earth results in deformation of the cable. After sufficient deformation has been attained, the cable loops extending below the line of ground deformation are sheared, resulting in a dead open circuit with no signal transmission. Those loops that are intact above the line of ground deformation within the borehole still conduct a signal. By measuring the electrical resistance readings, once can ascertain approximately at what depth the ground is experiencing deformation, as those loops extending below the level of ground displacement will show either a high, or an infinite, resistance.  
         [0013]     There does not appear to be any relevant patented, or non-patented, references noted for the system proposed herein. The references relate either to TDR devices or resistance devices as stand alone systems.  
       SUMMARY  
       [0014]     In view of the insufficiencies discussed above, it is an object of the present invention to provide a pacifier assembly having a cover movably mounted to the shield.  
         [0015]     It is a further object of the invention to provide a pacifier assembly which can protect the nipple of the pacifier and which decreases the inconveniences derived from the pacifier falling on the floor.  
         [0016]     The present invention is a substance displacement device. The device includes a sensing unit which is positioned in a drill hole or otherwise within the substance, such as soil or rock. A measurement device is connected to the sensing unit to measure changes in resistance caused by deformation of the sensing device. A control device connected to the measuring device determines whether the change in resistance exceeds a threshold, and thus activates an alarm.  
         [0017]     The sensing device preferably includes a fixed resistance device across its terminations to enable the establishing of a baseline resistance. The sensing device may include an electrical element or an optical element. The alarm can be any suitable type of alarm.  
         [0018]     Other features and advantages of the invention will be apparent from the following detailed description taken in conjunction with the following drawings. 
     
    
     DRAWING FIGURES  
       [0019]     In the drawings, closely related figures may have the same number but different alphabetical suffixes.  
         [0020]      FIG. 1  shows the general configuration of the cable monitoring system installed in a geologic material.  
         [0021]      FIG. 2  shows a detailed cross section axially along the borehole as depicted in  FIG. 1  with a single sensor cable.  
         [0022]      FIG. 3  shows the general configuration of the cable monitoring system installed in a geologic material with a multiple strand sensor.  
         [0023]      FIG. 4  shows a detailed cross section axially along the borehole as depicted in  FIG. 3  showing a multiple sensor cable.  
         [0024]      FIG. 5  shows the general configuration of the cable monitoring system installed in a geologic material for a convoluted conduit/external TDR cable.  
         [0025]      FIG. 6  shows a detailed cross section axially along the borehole as depicted in  FIG. 5  showing the convoluted conduit shrouded cable and external TDR monitoring cable.  
         [0026]      FIG. 7  shows a detailed diametric cross section of the borehole with the convoluted to shroued cable and external TDR monitoring cable.  
         [0027]      FIG. 8  shows, in axial section, the convoluted cable enshrouding the sensor cable prior to deformation of the shroud.  
         [0028]      FIG. 9  shows, in axial section, the convoluted cable enshrouding the sensor cable post deformation of the shroud.  
         [0029]      FIG. 10  depicts a cut and fill mining system with the backfilled mining room between two rock pillars. Monitoring system installed to detect shear between fill and pillars.  
         [0030]      FIG. 11  depicts a sectional view of a surface mount of the monitoring cable system on a rock face.  
         [0031]      FIG. 12  depicts an alternative configuration of the pressure sensitive resistant device that mau be used as a portion cable monitoring system. 
     
    
     REFERENCE NUMERALS IN DRAWINGS  
       [0032]     The following reference numerals are found in the drawings and have the indicated designations: 
     101  geologic material (rock or soil)      102  locus of ground dislocation      103  pressure sensitive cable (resistance varying)      104  resistor      105  resistance measurement apparatus      106  resistance measurement and alarm controller      107  alarm circuit      108  coaxial cable      109  ----      110  a controller/ID/resistance-measuring device      111  electrical lead      112  electrical lead      113  ----      114  multiple device controller      115  backfilled stopes (mining rooms)      116  underground openings above mining areas      117  underground openings below or adjacent to mining areas      118  surface anchor (mechanical or adhesive)      119  electrical bus      120  global representation of pressure sensitive ground motion system      121  ----      122  ----      123  ----      124  ----      128  ----      129  ----      130  convoluted conduit      131  grout      132  open annulus between outer conduit and inner cable      133  impingement of conduit on sensor  103       134  anchor device      135  borehole in geologic material      136  standard coaxial cable      137  shroud or protective covering      139  water and/or gas resistant membrane      140  water sealing end cap      141  ----      142  deformation of outer conduit upon ground displacement      143  ----      144  conductor      145  dielectric    
 
       DETAILED DESCRIPTION  
       [0074]     While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated.  
         [0075]     A sensor with electrical resistance properties that vary as a function of pressure is placed within, or upon, a rock, soil, or man made material. The sensing portion of the device may be located within the material, such as being cast in place, placed within a drillhole, or placed in a trench. The sensing portion of the device may also be placed on the surface of the material to be monitored.  
         [0076]     The device consists of a measurement unit, a sensing unit, and a control device. The sensing unit is any device such that when subjected to pressure/deformation results in a change in measurable resistance, either optical or electrical. As such this device must at some point form a complete circuit. For the electrical case, this can be prior to the sensing unit being subjected to pressure, where two conductors are connected via a diode, resistor, encoded electrical identifier or other component. This connection may also be created by the application of pressure resulting in a connection between conductors, either by direct contact or through a material which changes conductance with a change in pressure. For the optical case, physical impingement upon the transmitting media results in dissipation and absorption of light such that a received light pulse in a perturbed sensor will be less than a light pulse received in a sensor which has not been disturbed, which is in effect a resistance. In either case, this sensing device is connected to a resistance measurement unit. The resistance measurement unit is connected to a control device. The control device monitors the resistance of the sensor device. When the control device detects a resistance that exceeds the alarm level thresholds the connected alarm device is triggered.  
         [0077]     The apparatus may be configured such that it incorporates a single sensing unit, or multiple sensing units connected via a conducting cable (coaxial, twisted pair, etc). A multiple device apparatus may consist of shorter segments of sensors attached to a conducting cable that is connected to a resistance measuring apparatus and alarm controller. Said controller/measurement unit monitors each shorter segment as an individual sensor. In this manner, sections of the geologic material can be monitored for movement instead of using a single device of greater length. This allows greater sensitivity and broadened usage.  
         [0078]     In either case, displacement of the geologic material in which a sensor is encapsulated, or is attached to, triggers a resistance change in said sensor at the point of ground dislocation, placing the sensor in shear, tension, or compression. A measurement circuit in the controller detects a resistance change within a sensor. If said resistance change is above a predetermined limit, an alarm device may be triggered. Said alarm device may consist of radio transmission to a base station, flashing lights, stench gas, or whatever alarm is required to provide adequate alert of ground motion.  
         [0079]     The device may be utilized in a stand-alone mode such that ground dislocation can be noted at surface. Alternatively, a sensor may be placed in parallel with a TDR (coaxial, twisted pair, etc) or OTDR (fiber optic, single mode, multimode, etc.) capable cable, or the sensor itself may be interrogated with TDR, OTDR, or resistance techniques. This allows detection of the actual location of ground movement along the length of the sensing unit downhole.  
         [0080]     Note that an important aspect of the sensor unit is the inclusion of a fixed resistance device across the termination of any individual pair of monitoring strains. By providing such a constant, measurable resistance downhole, a baseline resistance can be determined for the senor. Any shear or short of the monitoring strands within the circuit will change the resistance of the sensor unit circuit. By this means, even standard coaxial cable can become a sensor unit, simply by installing a resistor of known capacity across the terminus of the cable between the inner and outer conductors.  
         [0081]     Turning now to the drawings where  FIG. 13  is a block diagram representation of electronic components  1000  comprising the present invention, a central processing unit (CPU)  1002  communicates with random access memory (RAM)  1004 , electrically erasable and programmable read only memory (EEPROM)  1006 , analog to digital converter (ADC)  1008 , and input output register (IO)  1010 . A real time clock oscillator  1022  may be used to form a real time clock-calendar by means of a program running upon said CPU. A communication interface  1020  may communicate with device  1000  for purpose of allowing commands and parameters to be input to the device to allow performance of the device to be altered by an operator. The device monitors a sensor  1018  to determine if predetermined conditions are met for an alarm. A method of allowing an operator to attach an alarm is provided by alarm relays  1012  and state of predetermined alarm conditions may be indicated to an operator by alarm indicators  1014 . A separate switchable relay power supply  1016  may be included to power relays. Said the CPU may disable relay power supply  1016  to save power when relays are not being actuated.  
         [0082]     Turning now to  FIG. 14 , which is a flowchart representation of a program that may run upon CPU  1002 , program starts at  1024  and continues on to  1026  where variables and input output ports are initialized. Program continues to  1028  where a decision is made as to whether a command has been received by means of communication through  1020  and if communication has been received, processes commands received in said communications at  1029  and then returns to  1028  to wait for further commands. If no command is received, program continues to  1030  where a low power mode is entered and processing is suspended but program is not exited. An interrupt routine  1042  triggered by means of  1022  causes processing to resume and at  1044  a decision is made as to whether processing was caused to resume by a clock tick. If a clock tick caused resumption of processing, program continues to  1046  where clock registers are updated and then on to  1048  where processing is suspended. If a clock tick did not cause suspension of processing, a predetermined time period has elapsed and program continues to  1032  where sensors are read by means of ADC  1008  and a determination is made at  1034  as to whether sensor values are within predetermined bounds. If sensor values are within predetermined bounds, program proceeds to  1036  where relays  1012  are set to states to so indicate; program continues to  1038  where indicators are set to inform an operator that predetermined alarm conditions have occurred; program then continues to  1028 . If at  1034  sensor values are outside of predetermined bounds, program continues on to  1040  where relays  1012  are set to states to indicate that no alarming condition has occurred after which program continues to  1041  where indicators are set to indicate that no alarm has occurred after which program continues to  1028 .  
       Typical Embodiment A  
       [0083]     A typical embodiment of the pressure sensitive device for determining if motion is occurring in a geologic material  101  is shown as  FIG. 1 . The pressure sensitive ground motion detection system, is globally represented as  120  within this Figure.  
         [0084]     As shown in section in  FIG. 2 , a cable with electrical resistance properties that vary as a function of pressure (Peratech QTC cable or similar)  103  is placed on or through a rock or soil mass (or man made equivalent)  101 . This may be within a drillhole (encased in grout or open), trench (buried or open), or by attachment to the material surface. The cable (sensor)  103  may be furnished with a resistor  104  at the end of said sensor furthest removed from the measuring device. The purpose of  104  is to provide an electrical connection between the two conductors utilized in cable  103  such that a complete electrical circuit is formed with a known resistance so complete cable shear can be detected. Cable  103  is then connected to a resistance measurement apparatus  105 . Said resistance measurement apparatus measures electrical resistance presented by sensor  103 . A controller  106  determines the interval at which the resistance of the sensor  103  is interrogated. Said controller  106 , is programmable such that a trigger resistance level can be set at which point an alarm circuit  107  is activated. Units  105 ,  106 , and  107  are presumed to be battery powered, although they can be powered by any other source of electrical energy. If displacement of the geologic material  101  is sufficient to induce a resistance change in the sensor  103  such that the controller  106  alarm level is exceeded, the alarm circuit  107  is activated. This alarm circuit  107  may consist of electronic transmissions to a base station, triggering of visual or sound alarms (flashing lights, sirens), stench alarms for noisy environments (heavy machine and drilling underground), etc. The sensor  103  may be interrogated by TDR (time domain reflectometry) techniques to determine the point of geologic dislocation (ground motion)  102 . Alternatively, a separate, parallel TDR capable cable (coaxial, twisted pair, etc) or OTDR (optical time domain reflectometry) fiber optic cable  108  may be installed together with  103 . Cable  108  may also be interrogated by TDR/OTDR to locate the physical point of ground displacement  102 . Note also that if the parallel cable  108  is equipped with a terminating resistor  104  downhole, then it may also be described as a sensor  103  and can be monitored in a similar fashion, as may the sensor  103  depending on its configuration.  
       Typical Embodiment B  
       [0085]     This embodiment is shown in  FIG. 3  with a sectional representation in  FIG. 4 .  
         [0086]     It is similar to the first embodiment described with the exception that multiple pressure sensing cables  103  are connected to an electrical bus  119 . Said electrical bus may consist of any suitable electrical conductors, with twisted pair or coaxial being preferred. Individual, shorter sections of sensor  103  are connected to the electrical bus by means of electrical leads  111  and  112 . Said electrical leads  111  and  112  connect to a controller/ID/resistance-measuring device  110 . Said controller/ID/resistance-measuring device associates a unique serial number (ID) with each segment of sensor  103  to which it is attached. When activated by a multiple device controller  114 , device  110  determines the resistance of each uniquely identified section of sensor  103 . Information obtain is communicated to multiple device controller  114 . Multiple segments of sensor  103  may be placed along a specific monitoring line (downhole, in a trench, along a surface) attached to electrical bus  119 . This enables a user to determine a specific interval along the monitoring line in which ground motion is occurring, as the multiple device controller can identify, by serial number, which sensor  103  segment has experienced ground motion. Alarm systems, reactions, and TDR/OTDR location of the ground motion from this point onward are consistent with the first embodiment.  
         [0087]     The obvious hybrids of the first two embodiments are also disclosed and claimed. These are the connection of electrical bus  110  to a single pressure sensitive device  103 , either with, or without, the usage of controller/ID/resistance measuring device  110 .  
       Typical Embodiment C  
       [0088]     This embodiment is depicted in  FIG. 5  with sectional representation in FIGS.  6  thru  9 .  
         [0089]     As for the first two embodiments, this depicts the deployment of the pressure sensitive ground motion system  120 , in a borehole drilled in a geologic or man made (concrete, etc) environment. A seventh embodiment is depicted in FIGS.  6  thru  9 . This embodiment incorporates a any sleeve or tubing, with a convoluted conduit  130  preferred, around the pressure sensitive device  103  shown here encapsulated in a grout  131 . The usage of a convoluted conduit is recommended with a user specified open annulus  132 ,  FIG. 8 . As the ground deforms, with corresponding conduit deformation  142 , annulus  132  closes and convolutions in said conduit impinge  133  on the pressure sensitive device  103 ,  FIG. 9 . These impingements increase the local resistance changes resulting in increased cable sensitivity. The downhole end of the conduit is may be equipped with a water sealing end cap  140  to prevent water intrusion into the conduit  130 . An anchoring device  134  may be attached to the bottom of conduit  130  and the pressure sensitive device  103  such that the assemblage will remain in place at the bottom of the drillhole. This anchor can consist of a weight, conical plastic diaphragm, deformed spring hooks (as shown), etc, or essentially any means to prevent the cable from displacing from its placed location in the drillhole  135 . To prevent local kinking at the collar of a drillhole, pressure sensitive device  103  has been electrically coupled to standard coaxial cable  136 . Kinking or damage in this location could produce erroneous readings. A protective shroud  137  has been placed over coaxial cable  136  and conduit  130  to prevent water intrusion into annulus  132 . An additional coaxial or fiber optic cable  108  may be placed adjacent to conduit  103  such that it can be utilized as a stand-alone method of monitoring, either for allowing a greater survivable time or greater accuracy in measuring deformation. This embodiment has application for rock faces in mines, highway cuts, etc. as well as soil faces for any excavation. Alarm activation and monitoring is as for the first listed embodiment.  
       Typical Embodiment D  
       [0090]     This embodiment is depicted in  FIG. 5  with sectional representation in FIGS.  6  thru  9 .  
         [0091]     As for the first two embodiments, this depicts the deployment of the pressure sensitive ground motion system  120 , in a borehole drilled in a geologic or man made (concrete, etc) environment. A seventh embodiment is depicted in FIGS.  6  thru  9 . This embodiment incorporates a any sleeve or tubing, with a convoluted conduit  130  preferred, around the pressure sensitive device  103  shown here encapsulated in a grout  131 . The usage of a convoluted conduit is recommended with a user specified open annulus  132 ,  FIG. 8 . As the ground deforms, with corresponding conduit deformation  142 , annulus  132  closes and convolutions in said conduit impinge  133  on the pressure sensitive device  103 ,  FIG. 9 . These impingements increase the local resistance changes resulting in increased cable sensitivity. The downhole end of the conduit is may be equipped with a water sealing end cap  140  to prevent water intrusion into the conduit  130 . An anchoring device  134  may be attached to the bottom of conduit  130  and the pressure sensitive device  103  such that the assemblage will remain in place at the bottom of the drillhole. This anchor can consist of a weight, conical plastic diaphragm, deformed spring hooks (as shown), etc, or essentially any means to prevent the cable from displacing from its placed location in the drillhole  135 . To prevent local kinking at the collar of a drillhole, pressure sensitive device  103  has been electrically coupled to standard coaxial cable  136 . Kinking or damage in this location could produce erroneous readings. A protective shroud  137  has been placed over coaxial cable  136  and conduit  130  to prevent water intrusion into annulus  132 . An additional coaxial or fiber optic cable  108  may be placed adjacent to conduit  103  such that it can be utilized as a stand-alone method of monitoring, either for allowing a greater survivable time or greater accuracy in measuring deformation. This embodiment has application for rock faces in mines, highway cuts, etc. as well as soil faces for any excavation. Alarm activation and monitoring is as for the first listed embodiment.  
       Typical Embodiment E  
       [0092]     This embodiment, shown in  FIG. 11 , depicts a surface application of the pressure sensitive ground motion system  120 . In this case, the system is deployed on the ground surface over geologic rock blocks or surfaces that may experience motion. Cable  103  is attached to the face by usage of adhesive or mechanical anchors  118 , spanning dislocation area  102 . Alarm activation and monitoring is as for the first listed embodiment.  
       Typical Embodiment F  
       [0093]     In this embodiment, the system  120  is deployed with cables  103  being located within a trench or drillholes underneath and area to be monitored. The sensing device  103  may be below a roadway, a housing project, etc. If subsurface subsidence (sinkholes, old mining excavations, etc) begin to break through to surface, they will induce motion in the ground, and thus vary resistance in the sensing device  103 , triggering the alarm circuit.  
       Typical Embodiment G  
       [0094]     This embodiment demonstrates an alternative method of construction of the pressure sensitive device  103 . This is shown in  FIG. 12 . In this embodiment, the pressure sensitive device  103  consists of a sandwich of two metallic conductors  144  (in this case, copper tape) attached to two sides of a pressure sensitive tape  145  (Peratech QTC tape or pressure sensitive underlay). This composite is then encapsulated in a waterproof sheath  139 , consisting of plastic or some other fluid or gas resistant membrane. When said composite structure is subjected to pressure, the electrical resistance of the pressure sensitive tape decreases, resulting in a low electrical resistance pathway between the two conductors  144 . Current flow can then be detected through the completed circuit, allowing it to be used as a pressure sensitive device  103 . Note also that, as the material is constructed from two conductors  144  separated my a dielectric material  145 , that it is possible to locate the distance along the device, at which point electrical bridging is occurring, using standard electrical TDR techniques.  
       Typical Embodiment H  
       [0095]     Here, the pressure sensitive sensor  103  is be replaced by a length of standard coaxial cable, twisted pair cable, or any other medium that will allow TDR interrogation, with the terminus of the cable pair (for coaxial cable this pair is the inner and outer conductor) is bridged with a resistor  104  of known resistance. A break in the circuit changes the system resistance, resulting in a detectable event for the alarm circuit.  
       Typical Embodiment I  
       [0096]     A preferred embodiment of the resistance measurement/controller/alarm circuit is described as follows:  
         [0097]     In one preferred embodiment of the current invention, CPU  1002 , RAM  1004 , EEPROM  1006 , ADC  1008  and IO  1010  may all be included in a semiconductor chip of a type ATMEGA 32 L manufactured by Atmel Corporation. A crystal of fundamental frequency 32.768 KHz manufactured by ECS CORPORATION may provide real time clock oscillator  1022 . Sensors may be of a type described in the body of the patent application (Peratech QTC cable  103  or similar equipped with resistor  104 ). Alarm relays  1012  may be of a type DS2Y-SL2-DC5V manufactured by Aromat Corporation. Relay power supply  1016  may be of a type MIC2145BMM manufactured by Micrel Corporation and communication interface  1020  may be of a type LMX 9820 manufactured by National Semiconductor Corporation. Alarm indicators  1014  may be comprised of any well-known low power light emitting diode (LED). Any well-known lithium ion battery may provide primary power for entire electronics assembly  1000 .  
       OPERATION  
       [0098]     The operation of the pressure sensitive cable device for monitoring rock and soil displacement is as follows.  
         [0099]     The pressure sensitive sensor  103  is constructed and installed as described in any of, but not limited to, the disclosed embodiments. Continuity and system resistance are checked and stored with the resistance measurement device  105  and controller  106 . Once this has been verified, the alarm level is set through the controller  106  and the alarm circuit  107 . This can be varied from dead short to dead open, or incremental resistance changes in between. The controller  106  then measures the resistance of the circuit at program selected time intervals using the resistance measurement device  106 . The measured resistance is then compared in the controller to the pre-programmed levels of resistance change required to trigger the alarm circuit.  
         [0100]     If a resistance level is found that exceeds the programmed alarm criteria for measured resistance, the controller  106  immediately conducts a control measurement of the system resistance. If the value once again indicates that the measured value exceeds pre-set resistance values for alarm, the alarm circuit is activated.  
         [0101]     Once the alarm circuit is activated, an alarm is initiated. Said alarm may consist of radio transmission to a base station, flashing lights, stench gas, or whatever alarm is required to provide alert of ground motion to targetted personnel.  
         [0102]     Upon alert, site personnel may take whatever action is necessary, such as closing areas to operation, etc. The system  120  has been designed such that it may be monitored with a time domain reflectometery (TDR) such that the location of ground displacement may be identified within the sensor  103 . This function reduces the necessity of reading the sensors or TDR cables on a frequent basis as monitoring the system resistance accomplishes much of the same function by indicating if ground displacement has taken place.  
         [0103]     After the alarm has been triggered, if the sensor  103  is still intact and capable of carrying an electrical signal, the alarm circuit  107  may be reset to a new level encompassing the resistance changes that have already occurred.  
         [0104]     It should be noted that in the electrical embodiments of the present invention, means for communication for purposes of control, command, and query may be by the means of personal digital assistance (PDA), such as, for example, of a model Tungsten T 2  manufactured by Palm, Inc.  
         [0105]     While the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.