CA1188734A - Method and device for detection of the presence of metal or mineral in a geologic mass - Google Patents
Method and device for detection of the presence of metal or mineral in a geologic massInfo
- Publication number
- CA1188734A CA1188734A CA000405287A CA405287A CA1188734A CA 1188734 A CA1188734 A CA 1188734A CA 000405287 A CA000405287 A CA 000405287A CA 405287 A CA405287 A CA 405287A CA 1188734 A CA1188734 A CA 1188734A
- Authority
- CA
- Canada
- Prior art keywords
- electrodes
- probe
- change
- potential difference
- mineral
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Geophysics And Detection Of Objects (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
For the detection of the presence of metal or mineral there is used a two electrode probe insertable into the geological formation. The two electrodes are manufactured from different types of material. When one electrode contacts a metal or mineral grain, the contact potential thereof is changed and there is a change of voltage between the electrodes. The change of voltage is passed to indicator means. After amplifying and possibly filtering the signals resulting from the change of voltage the indicator means indicates the change of potential in one or several audio visual components. The magnitude of the change of potential indicates the type of metal or mineral that has been found.
For the detection of the presence of metal or mineral there is used a two electrode probe insertable into the geological formation. The two electrodes are manufactured from different types of material. When one electrode contacts a metal or mineral grain, the contact potential thereof is changed and there is a change of voltage between the electrodes. The change of voltage is passed to indicator means. After amplifying and possibly filtering the signals resulting from the change of voltage the indicator means indicates the change of potential in one or several audio visual components. The magnitude of the change of potential indicates the type of metal or mineral that has been found.
Description
'7~1 The present invention relates to a method and a device for detecti.on of -the presence of metal or mineral in a geological formation.
~ hen searching for metals or minerals there have been used different electrical apparatuses and methods. However, all have been expensive and/or difficult to operate.
The present invention is based on the fact that every metal or mineral has its own specific electrical potential. Com-pared to hydrogent which frequently J.S used as a reference and referred to as "earth", for instance coba:Lt, nickel and tin are negative, whil.e plantinum, gold and silver are posi-tive. Inert metals are clearly positive and in relation to said metals almost all remaining me-tals are nega-tive. Metals and minerals may be arranged in a so called potentia]. chain Co Ni Sn U-1.40 Zn-0.76 -0.29-0.23-0.14 Cu+0.51 Ag+0.80 Au+1.36 -1.5V -lV -0.5V +0 ~0.5V -lV +1.5V
which clearly illustrates the variation in contact potentials.
It is possible to use a two-pole probe connected to a display member, and to insert the probe into the ground or a geological formation, whereby the contact between one of -the poles and metal or mineral grains of the formation result in a deflection on the display member. However, it is necessary to know with acceptable reliability what type of material the probe has contac-ted. When a metal or mineral grain contacts one of the poles the potential difference between the poles is changed. Changes of potential may be processed and recorded in several ways, and present day technology offers a wide varie-ty of amplifying and separating methods.
The potential difference between the poles of the probe, inter alia, depends on what type of material the poles are manu-factured from. If the probe tip contacts a metal grain, or ~8~73~L
generally a grain of electr:i.cally detectable material, the poten-tial is changed. The magnitude of the change of potential de-pends inter alia on the size of the grain and the material and shaped thereof. The poten-tlal change thus obtained in the form of a signal, may be processed in an electronic unit to give an indication of the presence of a metal grain. If one pole of the probe, for instance in the shape of a tip, when being inserted in the ground contacts a number of grains, there is a shower of signals- In the elec-tronic unit it is quite possible to incor-porate several facili.ties in order to separate different signals.
It is possible to give the tip a certain bias to obtain a thres-hold potential where certain minerals g:Lve positive and othernegative voltage deflections. It is also possible to use threshold levels for avoiding low level signals. Filtering rnay be done in several ways and the number of pulses per time unit may be counted to open a gate to the indicator member when a sufficiently high pulse frequency exists.
According to the present invention there is provided a method for detecting the presence of me-tal or mineral in a geo-logical formation which comprises inserting a probe into the formation which is connected to a display member, the probe having two electrodes of diEferent material, between which a known poten-tial difference exists, the display member including means for indicating change of potential caused by contact between one electrode and metal or mineral grains in the formation.
Thus according to the present invention there is provided a method of detecting the presence of grains of at least one of the kinds metal and mineral in a geologic formation~ comprising providing a probe having two exposed electrodes electrically insulated from each other in said probe and being of different types of material so as to give a prede-termined potential differ-ence between the electrodes when in a moistened mass, insertingthe probe in a geological formation having at least a certain ~ - 2 -3~
moisture therein; elec-tronically detec-ting, while the probe is being inserted, an instantaneous change of the potential difEerence between the electrodes of the probe caused by a grain of said of at least one of the kinds me-tal and mineral instantaneously con-tacting one of said electrodes, thereby chanying the so-called contact potential of the electrode; and electronically processing a detected chanye of potential difference between said electrodes caused by such contact be-tween a grain and one electrode -to pro-vide an indication of said con-tac-t.
Preferably, the second electrode has a considerably larger contact surface area than the first electrode. In order to simplify the identifica-tion of a certain metal or mineral being searched for, the electrodes are biassed to a voltage of lcnown level, less than the expected voltage deflection.
The display member preferably is adapted to show mag-nitude as well as polarity.
An apparatus for carrying out the method comprises a probe provided with two electrodes of different material and a display member comprising at least one component arranged for indicating a change of potential caused by contact between one pole and metal or mineral grains in the geological formation.
Thus the present invention also provides an apparatus for detecting the presence of grains of at least one of the kinds metal and mineral in a geoloyic formation, comprising a probe having two exposed electrodes electrically insulated from each other and being of different types of material, the probe being adapted to be inserted into a geological formation and the elect-rodes being chosen to give a predetermined potential difference between the electrodes when in a moistened mass, electronic detect-ing means for detecting an instantaneous change of the potentialdifference between the electrodes caused by a grain of said grains instantaneously contacting one of said electrodes while the probe 3~
is being inser-ted into a yeologic forma-tion having a-t least a certain moisture thereini and electronic processing means for processing a change oE the potential difference detec-ted by said electronic detectiny means, for providing an indication thereof.
A current source connected between the electrodes pre-ferably is arranged for biassing the electrodes at a known volt-age. The display member preferably comprises a component arranged to indicate the magni-tude as well as the type of potential differ-ence.
The other electrode preferably is shaped as an elonga-ted, electrically conducting pipe, at the one end thereof having a tip electrically insulated from the res-t of the pipe and form-ing the other electrode. The ti.p may be resiliently connected to the pipe to prevent damage to the probe and facilitate the penetration into the Eormation.
The tip may be divided into several parts and also comprise parts of different material. Furthermore, the pipe may be of a flexible, resilient material having an electrically conducting surface layer. It may be sufficient to use only one type of display member, but there are also other types of such members, for instance a hidden, movable part within the hand but invisible to others.
The accompanying drawing is a vertical section through a rod~shaped probe, inserted into the geological formation to-gether with display and/or indicator members.
In the method of the present invention an easily trans-portable probe 10 is used, comprising a pipe 11 of suitable length, at least one end 12 being formed of a strong, metallic material, for instance stainless steel. The probe is provided with a handle 13 which facilitates the pushing down or screwing into the formation.
At the end 12 of the pipe remote from the handle there 3~
is a pointed body 14, for ins-tance man~Eactured from a hard me,al, insertable into -the pipe so as to be electrically insulated from the pipe 11. Suitably, the insulation may comprise a glue 27 making it possible to change the bo~y when required.
The tip as such of the body cornprises a 21urali-ty of disks 16 separated from each other hy grooves comprising an electrically insulating mass 15. Each disk 16 has a relatively small con-tact surface, while the pipe 12 has a considerable con-tact surface and is "yrounded". The la-tter contact surface will not be noticeably affected by rnineral grains around the surface.
Via a cable 17 the probe 10 is connected to a display member 18. A lead 19 of the cable is connected to the tip 14, and a lead 20 is connected to the pipe 12.
The display member 18 is connected to a current source 21, for instance an accumulator type of battery, and comprises an amplifier and other type of conventional electronic e~uipment.
Signals that are received are indicated by audio visual members of conventional type, for instance a lamp or light diode 22, volt meter 23, and/or display 24 and ear phones 25.
In the drawing, the presence of different types of metal or mineral grains is indicated by the references 26a, b, c.
There are different types of material in the two electro-des 12 and 14, and by utilizing for instance common type of soil or water as an "electrolyte" this results (preferably after fil-terins) in a low level signal in the ear phones. Contact between a disk 16 and a metal or mineral grain of any type results in a "click" of variable strength. An experienced operator is able to estimate the reilability of the existence of a certain mineral, merely by means of the sound, but for a more exact registration there is used one or some of the members 22-24.
As mentioned hereinbefore, each metal or mineral has its own typical potential of a certain level, and by using the magnitude ~ - 5 -7~
of the change of poten-tial it is possible to identify what type of mineral the probe has contacted. Frequently, it is suitable to arrange for instance the display 24 such that it also i.ndicates the pol.arity in addi-tion to the magni.tude of the change of poten-ti.al.
If one is look.ing for a certain metal, for instance gold, which is to be found ~ui-te a dis-tance ou-t on the positive side of the contact potential chain, it is possible to blas the poles 12 and 14 via the cable 17, and eventually filter away certain sig-nals. This re.sults in that, :Erom a practical point of view, merelythe gold grains looked for are able to cause any change of the potential pattern.
In order to reduce the risk for damage, the tip 14 may be mounted resiliently in the pi.pe, and the tip itself may be shaped as an obliquely cut cylinder simplifying the passage past stones and the like in the formation. In certain layers of a formation it may be of advantage to shape the tip, or the pipe, ; such that the probe is screwed down. For the surveillance of the sea-bottom where the depth of the water is such that a rod-shaped probe is not well suited, the probe may be formed as a heavy body, which hanging on a wire is "pushed" down into the sea-bottom.
A certain moisture in the formation is a requirement for obtaining a potential difference between the electrodes. When operating in a very dry formation it may be necessary to provide the probe with means for spraying moisture around the tip and/or the pipe.
~ - 6 -
~ hen searching for metals or minerals there have been used different electrical apparatuses and methods. However, all have been expensive and/or difficult to operate.
The present invention is based on the fact that every metal or mineral has its own specific electrical potential. Com-pared to hydrogent which frequently J.S used as a reference and referred to as "earth", for instance coba:Lt, nickel and tin are negative, whil.e plantinum, gold and silver are posi-tive. Inert metals are clearly positive and in relation to said metals almost all remaining me-tals are nega-tive. Metals and minerals may be arranged in a so called potentia]. chain Co Ni Sn U-1.40 Zn-0.76 -0.29-0.23-0.14 Cu+0.51 Ag+0.80 Au+1.36 -1.5V -lV -0.5V +0 ~0.5V -lV +1.5V
which clearly illustrates the variation in contact potentials.
It is possible to use a two-pole probe connected to a display member, and to insert the probe into the ground or a geological formation, whereby the contact between one of -the poles and metal or mineral grains of the formation result in a deflection on the display member. However, it is necessary to know with acceptable reliability what type of material the probe has contac-ted. When a metal or mineral grain contacts one of the poles the potential difference between the poles is changed. Changes of potential may be processed and recorded in several ways, and present day technology offers a wide varie-ty of amplifying and separating methods.
The potential difference between the poles of the probe, inter alia, depends on what type of material the poles are manu-factured from. If the probe tip contacts a metal grain, or ~8~73~L
generally a grain of electr:i.cally detectable material, the poten-tial is changed. The magnitude of the change of potential de-pends inter alia on the size of the grain and the material and shaped thereof. The poten-tlal change thus obtained in the form of a signal, may be processed in an electronic unit to give an indication of the presence of a metal grain. If one pole of the probe, for instance in the shape of a tip, when being inserted in the ground contacts a number of grains, there is a shower of signals- In the elec-tronic unit it is quite possible to incor-porate several facili.ties in order to separate different signals.
It is possible to give the tip a certain bias to obtain a thres-hold potential where certain minerals g:Lve positive and othernegative voltage deflections. It is also possible to use threshold levels for avoiding low level signals. Filtering rnay be done in several ways and the number of pulses per time unit may be counted to open a gate to the indicator member when a sufficiently high pulse frequency exists.
According to the present invention there is provided a method for detecting the presence of me-tal or mineral in a geo-logical formation which comprises inserting a probe into the formation which is connected to a display member, the probe having two electrodes of diEferent material, between which a known poten-tial difference exists, the display member including means for indicating change of potential caused by contact between one electrode and metal or mineral grains in the formation.
Thus according to the present invention there is provided a method of detecting the presence of grains of at least one of the kinds metal and mineral in a geologic formation~ comprising providing a probe having two exposed electrodes electrically insulated from each other in said probe and being of different types of material so as to give a prede-termined potential differ-ence between the electrodes when in a moistened mass, insertingthe probe in a geological formation having at least a certain ~ - 2 -3~
moisture therein; elec-tronically detec-ting, while the probe is being inserted, an instantaneous change of the potential difEerence between the electrodes of the probe caused by a grain of said of at least one of the kinds me-tal and mineral instantaneously con-tacting one of said electrodes, thereby chanying the so-called contact potential of the electrode; and electronically processing a detected chanye of potential difference between said electrodes caused by such contact be-tween a grain and one electrode -to pro-vide an indication of said con-tac-t.
Preferably, the second electrode has a considerably larger contact surface area than the first electrode. In order to simplify the identifica-tion of a certain metal or mineral being searched for, the electrodes are biassed to a voltage of lcnown level, less than the expected voltage deflection.
The display member preferably is adapted to show mag-nitude as well as polarity.
An apparatus for carrying out the method comprises a probe provided with two electrodes of different material and a display member comprising at least one component arranged for indicating a change of potential caused by contact between one pole and metal or mineral grains in the geological formation.
Thus the present invention also provides an apparatus for detecting the presence of grains of at least one of the kinds metal and mineral in a geoloyic formation, comprising a probe having two exposed electrodes electrically insulated from each other and being of different types of material, the probe being adapted to be inserted into a geological formation and the elect-rodes being chosen to give a predetermined potential difference between the electrodes when in a moistened mass, electronic detect-ing means for detecting an instantaneous change of the potentialdifference between the electrodes caused by a grain of said grains instantaneously contacting one of said electrodes while the probe 3~
is being inser-ted into a yeologic forma-tion having a-t least a certain moisture thereini and electronic processing means for processing a change oE the potential difference detec-ted by said electronic detectiny means, for providing an indication thereof.
A current source connected between the electrodes pre-ferably is arranged for biassing the electrodes at a known volt-age. The display member preferably comprises a component arranged to indicate the magni-tude as well as the type of potential differ-ence.
The other electrode preferably is shaped as an elonga-ted, electrically conducting pipe, at the one end thereof having a tip electrically insulated from the res-t of the pipe and form-ing the other electrode. The ti.p may be resiliently connected to the pipe to prevent damage to the probe and facilitate the penetration into the Eormation.
The tip may be divided into several parts and also comprise parts of different material. Furthermore, the pipe may be of a flexible, resilient material having an electrically conducting surface layer. It may be sufficient to use only one type of display member, but there are also other types of such members, for instance a hidden, movable part within the hand but invisible to others.
The accompanying drawing is a vertical section through a rod~shaped probe, inserted into the geological formation to-gether with display and/or indicator members.
In the method of the present invention an easily trans-portable probe 10 is used, comprising a pipe 11 of suitable length, at least one end 12 being formed of a strong, metallic material, for instance stainless steel. The probe is provided with a handle 13 which facilitates the pushing down or screwing into the formation.
At the end 12 of the pipe remote from the handle there 3~
is a pointed body 14, for ins-tance man~Eactured from a hard me,al, insertable into -the pipe so as to be electrically insulated from the pipe 11. Suitably, the insulation may comprise a glue 27 making it possible to change the bo~y when required.
The tip as such of the body cornprises a 21urali-ty of disks 16 separated from each other hy grooves comprising an electrically insulating mass 15. Each disk 16 has a relatively small con-tact surface, while the pipe 12 has a considerable con-tact surface and is "yrounded". The la-tter contact surface will not be noticeably affected by rnineral grains around the surface.
Via a cable 17 the probe 10 is connected to a display member 18. A lead 19 of the cable is connected to the tip 14, and a lead 20 is connected to the pipe 12.
The display member 18 is connected to a current source 21, for instance an accumulator type of battery, and comprises an amplifier and other type of conventional electronic e~uipment.
Signals that are received are indicated by audio visual members of conventional type, for instance a lamp or light diode 22, volt meter 23, and/or display 24 and ear phones 25.
In the drawing, the presence of different types of metal or mineral grains is indicated by the references 26a, b, c.
There are different types of material in the two electro-des 12 and 14, and by utilizing for instance common type of soil or water as an "electrolyte" this results (preferably after fil-terins) in a low level signal in the ear phones. Contact between a disk 16 and a metal or mineral grain of any type results in a "click" of variable strength. An experienced operator is able to estimate the reilability of the existence of a certain mineral, merely by means of the sound, but for a more exact registration there is used one or some of the members 22-24.
As mentioned hereinbefore, each metal or mineral has its own typical potential of a certain level, and by using the magnitude ~ - 5 -7~
of the change of poten-tial it is possible to identify what type of mineral the probe has contacted. Frequently, it is suitable to arrange for instance the display 24 such that it also i.ndicates the pol.arity in addi-tion to the magni.tude of the change of poten-ti.al.
If one is look.ing for a certain metal, for instance gold, which is to be found ~ui-te a dis-tance ou-t on the positive side of the contact potential chain, it is possible to blas the poles 12 and 14 via the cable 17, and eventually filter away certain sig-nals. This re.sults in that, :Erom a practical point of view, merelythe gold grains looked for are able to cause any change of the potential pattern.
In order to reduce the risk for damage, the tip 14 may be mounted resiliently in the pi.pe, and the tip itself may be shaped as an obliquely cut cylinder simplifying the passage past stones and the like in the formation. In certain layers of a formation it may be of advantage to shape the tip, or the pipe, ; such that the probe is screwed down. For the surveillance of the sea-bottom where the depth of the water is such that a rod-shaped probe is not well suited, the probe may be formed as a heavy body, which hanging on a wire is "pushed" down into the sea-bottom.
A certain moisture in the formation is a requirement for obtaining a potential difference between the electrodes. When operating in a very dry formation it may be necessary to provide the probe with means for spraying moisture around the tip and/or the pipe.
~ - 6 -
Claims (13)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of detecting the presence of grains of at least one of the kinds metal and mineral in a geologic formation, comprising providing a probe having two exposed electrodes electri-cally insulated from each other in said probe and being of different types of material so as to give a predetermined potential difference between the electrodes when in a moistened mass, inserting the probe in a geological formation having at least a certain moisture therein; electronically detecting, while the probe is being inser-ted, an instantaneous change of the potential difference between the electrodes of the probe caused by a grain of said at least one of the kinds metal and mineral instantaneously contacting one of said electrodes, thereby changing the so-called contact poten-tial of the electrode; and electronically processing a detected change of potential difference between said electrodes caused by such contact between a grain and one electrode to provide an indication of said contact.
2. A method according to claim 1, wherein said electroni-cally processing includes the provision of an audio signal.
3. A method according to claim 1 wherein said electronically processing includes determining the magnitude of the change of potential difference and providing a display thereof.
4. A method according to claim 3, wherein said elec-tronically processing also includes determining a polarity of the change of potential difference and providing a display thereof.
5. An apparatus for detecting the presence of grains of at least one of the kinds metal and mineral in a geologic for-mation, comprising a probe having two exposed electrodes electri-cally insulated from each other and being of different types of material, the probe being adapted to be inserted into a geological formation and the electrodes being chosen to give a predetermined potential difference between the electrodes when in a moistened mass; electronic detecting means for detecting an instantaneous change of the potential difference between the electrodes caused by a grain of said grains instantaneously contacting one of said electrodes while the probe is being inserted into a geologic formation having at least a certain moisture therein; and elec-tronic processing means for processing a change of the potential difference detected by said electronic detecting means, for pro-viding an indication thereof.
6. An apparatus according to claim 5, wherein said electronic processing means provide an audible indication.
7. An apparatus according to claim 5, wherein said electronic processing means include display means for displaying an indication.
8. An apparatus according to claim 5, wherein the probe includes an elongated pipe forming one of said electrodes and a pointed tip portion mechanically connected to an end of the pipe and electrically insulated therefrom, the tip portion forming the other of said electrodes.
9. An apparatus according to claim 8, wherein the poin-ted tip portion includes a number of discs separated by electri-cally insulating spacer means and electrically connected to each other to form said other electrode.
10. An apparatus according to claim 9, wherein the planes of the discs are transverse to the extension of said pipe.
11. An apparatus according to claim 8, wherein said other electrode has a considerably less contact surface area than said one electrode.
12. A method according to claim 1 or 2, wherein the electrodes are biased at a predetermined voltage level.
13. An apparatus according to claim 11, further com-prising means for biasing the electrodes at a predetermined volt-age level.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8106118A SE8106118L (en) | 1981-04-29 | 1981-10-16 | PROCEDURE AND DEVICE FOR DETECTING THE EXISTENCE OF METAL OR MINERALS IN A GEOLOGICAL MASS |
| SE8106118-6 | 1981-10-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1188734A true CA1188734A (en) | 1985-06-11 |
Family
ID=20344808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000405287A Expired CA1188734A (en) | 1981-10-16 | 1982-06-16 | Method and device for detection of the presence of metal or mineral in a geologic mass |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU549689B2 (en) |
| BR (1) | BR8203728A (en) |
| CA (1) | CA1188734A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014100858A1 (en) | 2012-12-24 | 2014-07-03 | Vdl Gold Pty Ltd | Process for mining alluvial deposits |
| CN104656147A (en) * | 2015-02-16 | 2015-05-27 | 山东大学 | Composite electrode device for direct-current electrical prospecting and operation method of composite electrode device |
| US11543375B2 (en) | 2018-06-29 | 2023-01-03 | Ejlskov A/S | Method, a system, and a probe for determining in-situ an oxidation-reduction potential in a formation having a surface |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE8301264D0 (en) * | 1983-03-08 | 1983-03-08 | Guldstroem Lars | SET AND DEVICE TO INDICATE EXISTENCE OF LEADING MATERIALS IN A MEDIUM |
-
1982
- 1982-06-16 CA CA000405287A patent/CA1188734A/en not_active Expired
- 1982-06-18 AU AU85016/82A patent/AU549689B2/en not_active Ceased
- 1982-06-25 BR BR8203728A patent/BR8203728A/en unknown
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014100858A1 (en) | 2012-12-24 | 2014-07-03 | Vdl Gold Pty Ltd | Process for mining alluvial deposits |
| CN104656147A (en) * | 2015-02-16 | 2015-05-27 | 山东大学 | Composite electrode device for direct-current electrical prospecting and operation method of composite electrode device |
| US11543375B2 (en) | 2018-06-29 | 2023-01-03 | Ejlskov A/S | Method, a system, and a probe for determining in-situ an oxidation-reduction potential in a formation having a surface |
Also Published As
| Publication number | Publication date |
|---|---|
| AU8501682A (en) | 1983-04-21 |
| AU549689B2 (en) | 1986-02-06 |
| BR8203728A (en) | 1984-01-10 |
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Legal Events
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| MKEC | Expiry (correction) | ||
| MKEX | Expiry |