U.S. patent application number 14/543255 was filed with the patent office on 2015-03-19 for method and apparatus usable for mining and mineral exploration.
The applicant listed for this patent is LynxRail Corporation. Invention is credited to Krzysztof Kilian, Taras Rudakov.
Application Number | 20150077111 14/543255 |
Document ID | / |
Family ID | 43496721 |
Filed Date | 2015-03-19 |
United States Patent
Application |
20150077111 |
Kind Code |
A1 |
Rudakov; Taras ; et
al. |
March 19, 2015 |
METHOD AND APPARATUS USABLE FOR MINING AND MINERAL EXPLORATION
Abstract
A method for mineral analysis of a sample based on detection of
NQR and/or NMR signals from a particular substance within a sample
includes: setting a frequency of RF pulses to be approximately
equal to one of the NQR or NMR frequencies of the substance;
setting a set of parameters of the RF pulses to be optimal for the
substance; setting a set of receiving parameters to be optimal for
the substance; tuning the probe to maximum sensitivity for the
signals detected at predetermined frequency and/or to maximum power
transfer efficiency for RF pulses transmitted with the probe;
transmitting the RF pulses with the probe at said optimal level
during a transmitting period to irradiate the sample and excite an
NQR or NMR signal in the substance, if present; detecting and
processing NQR or NMR signals emitted by the substance; and
calculating the concentration of the substance in the sample.
Inventors: |
Rudakov; Taras; (Canning
Vale, AU) ; Kilian; Krzysztof; (Colorado Springs,
CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LynxRail Corporation |
Colorado Springs |
CO |
US |
|
|
Family ID: |
43496721 |
Appl. No.: |
14/543255 |
Filed: |
November 17, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13930441 |
Jun 28, 2013 |
8917092 |
|
|
14543255 |
|
|
|
|
12842285 |
Jul 23, 2010 |
8497678 |
|
|
13930441 |
|
|
|
|
61228798 |
Jul 27, 2009 |
|
|
|
Current U.S.
Class: |
324/309 |
Current CPC
Class: |
G01N 24/081 20130101;
G01V 3/32 20130101; G01R 33/3808 20130101; G01N 24/08 20130101;
G01R 33/441 20130101 |
Class at
Publication: |
324/309 |
International
Class: |
G01N 24/08 20060101
G01N024/08; G01R 33/44 20060101 G01R033/44 |
Claims
1. A method for the mineral analysis of a sample to determine if
the sample contains at least a first desired substance, the first
desired substance having nuclei responsive to a Nuclear Quadrupole
Resonance (NQR) and/or Nuclear Magnetic Resonance (NMR) field
phenomenon in a local magnetic field, the method comprising:
exciting and detecting NQR and/or NMR signals from an amount, if
present, of the first desired substance within the sample using
radio-frequency (RF) pulses; measuring the intensity of any
detected NQR and/or NMR signal; determining the concentration of
the first desired substance in the sample being analyzed based on
the intensity of any detected NQR and/or NMR signals; and receiving
and processing at least one response signal to detect a presence of
an NQR or NMR signal corresponding to the first desired substance.
Description
[0001] This application claims priority as a continuation
application of U.S. patent application Ser. No. 13/930,441 filed
Jun. 28, 2013, which is a continuation application of U.S. patent
application Ser. No. 12/842,285 filed Jul. 23, 2010 now U.S. Pat.
No. 8,497,678, which claims priority to and benefit of U.S.
Provisional Application 61/228,798 filed on Jul. 27, 2009, each of
which are incorporated herein by reference in their entirety.
BACKGROUND
[0002] 1. Field
[0003] This invention relates to a method and apparatus for a
mineralogy analysis. This invention more particularly relates to a
method and apparatus for ore grade estimation.
[0004] 2. Background
[0005] Different active nuclear techniques have been widely used to
produce information on the chemical composition of rocks and ore in
the laboratory conditions. These techniques include gamma-ray
spectrometry, X-ray fluorescence (XRF) and neutron activation.
These techniques are not widely used for mining operations (e.g.,
in blast holes and exploration holes) because, for example, no
single nuclear technique is sufficiently useful alone (e.g., none
of the known techniques can solve a sufficient number of the
common, relevant ore estimation problems).
[0006] Known neutron activation (e.g., neutron gamma-ray) methods
may be used for measuring a concentration of one or more metals,
such as copper, manganese and nickel in ore.
[0007] Nuclear Magnetic Resonance (NMR) is widely used as a
borehole logging method for the oil and gas exploration. The
characterization of hydrocarbon reservoirs in subsurface earth
formation is of considerable interest in the oil and gas industry.
In this industry, NMR is used for detecting proton resonance in
liquids.
SUMMARY
[0008] It should be appreciated that the term "substance" as used
in the following description, may be taken to mean those desired
materials and/or substances which respond in a desired way to NQR
and/or NMR phenomenon and techniques.
[0009] Many substances that are relevant in detecting explosives
contain quadrupolar nuclei, such as, for example, nitrogen-14 (14N)
and can be detected using NQR methods. The spectral lines of such
substances are located at low frequencies, where detected NQR
signals have very low intensity.
[0010] However, a number of problems associated with deploying NQR
techniques in the field as a reliable and sensitive technique to
ascertain the presence of the targeted substance have arisen,
limiting the functionality and/or the feasibility of such
techniques. For example, low intensity of NQR signals, external
interferences and/or spurious signals, which can be detected from
surrounding items each, in various ways, may reduce the
functionality and/or feasibility of using NQR techniques in the
field.
[0011] Likewise, direct detection of ore zones by using borehole
gamma-ray spectrometry is limited to radioactive minerals. As such,
indirect detection (e.g., potassium-enriched sericitic or
feldspathic alteration associated with gold mineralization) and
characteristics of host rock (e.g., phases of kimberlite) are
normally used for these purposes.
[0012] Further, XRF methods are not widely used in exploration and
mining borehole logging primarily because of the low energies
involved and hence the shallow depth of penetration (e.g., limited
analysis, if any, beyond a surface analysis) and because the
borehole conditions (e.g., surface rugosity) have a large effect on
the result. Additionally, the low energies detected often require a
relatively thin window over the detector, which may be vulnerable
under water-filled borehole conditions.
[0013] Furthermore, active nuclear techniques use radioactive
sources, which may be unsafe for surrounding humans, animals, plant
life and/or equipment. As such, active nuclear systems are
predominantly used, if at all, in a borehole-logging configuration,
in which the radioactive source is safely contained in the hole
during the measurements. It should be appreciated that the
radioactive source may be in the form of a radioisotope, an
electronic source (e.g., X-ray tubes or neutron generators) and/or
any other known or later-developed radioactive source.
[0014] Additionally, active nuclear techniques generally cannot
directly distinguish between different minerals that contain the
same element or elements.
[0015] Due, at least in part, to the many difficulties involved
with using active nuclear techniques, such techniques are not
widely used for mine site exploration and/or ore delineation.
[0016] Likewise, the application of conventional NMR methods for
mineral analysis is currently very limited. Solid state NMR
requires complicated equipment and special detection techniques.
Therefore, the method is mostly used in laboratory conditions.
[0017] Nuclear Quadrupole Resonance (NQR) techniques have been
suggested as being useful in borehole logging methods for minerals
bearing such elements as boron, lithium and potassium. Such NQR
methods may be preferable over other available methods for any of
at least the following reasons: it is a non-radioactive,
non-hazardous and/or non-invasive method; it is suitable for the
quantitative analysis of solids in place; and/or it is relatively
inexpensive and fast.
[0018] However, the previously-known detection methods are based on
using continuous wave techniques, which may not be efficient,
robust and/or sensitive enough to be used for analysis of many
desired minerals.
[0019] An exemplary method, technique and/or apparatus according to
this invention may be particularly useful in mining operations for
mine site exploration and/or ore delineation. However, it should be
appreciated that various exemplary embodiments of methods,
techniques and/or apparatuses according to this invention may be
used in other applications, such as, for example assessing mineral
content and/or distribution within rock bodies in situ, in soils or
sands, in other geological contexts and/or in research.
[0020] In various exemplary embodiments of a method and/or an
apparatus according to this invention, the method and/or apparatus
is usable for mineralogy analysis and/or optimal ore grade
estimation for the purpose of mine site exploration and/or ore
delineation. In various exemplary embodiments, such methods and/or
apparatuses do not exhibit some or all of the disadvantages
associated with previous detection methods and systems.
[0021] In various exemplary embodiments, a method, apparatus and/or
system according to this invention is usable to provide a
non-radioactive method with sensitivity and accuracy similar to or
better than conventional radioactive nuclear methods.
[0022] In various exemplary embodiments, a method according to this
invention is usable for distinguishing, differentiating between
and/or measuring concentrations of different minerals containing
one or more of the same element(s).
[0023] In various exemplary embodiments, nuclear quadrupole
resonance (NQR) and nuclear magnetic resonance (NMR) phenomenon and
detection techniques are used.
[0024] It should be appreciated that both NQR and NMR techniques
are forms of radio frequency (RF) spectroscopy. Likewise, NQR and
NMR are both non-radioactive methods that can be utilized to detect
and investigate various chemical compounds. These methods may also
be used to detect the presence of specific desired substances, such
as, for example, explosives and/or narcotics.
[0025] In various exemplary embodiments, NQR methods are used for
the analytical detection of chemical substances in solid form. Such
NQR methods may provide both elemental composition and mineral
phase of bulk material.
[0026] Further, in various exemplary embodiments, the NQR methods
may be used to characterize many desired compounds (e.g., more than
10,000). Such compounds may include various different elements in
the periodic table, which make them desirable. for example, there
are a number of nuclei, such as Copper (e.g., 63Cu, 65Cu), Cobalt
(e.g., 59Co), Titanium (e.g., 47Ti, 49Ti), Rhenium (e.g., 127Re),
Manganese (e.g., 55Mn), Aluminium (e.g., 27Al), Bismuth (e.g.,
209Bi), Arsenic (e.g., 75As), Antimony (e.g., 123Sb), Indium (e.g.,
115I), and Gallium (e.g., 71Ga) etc., which are important to
various industries, and thus may be desirable to identify.
[0027] NQR may be defined as a phenomenon of resonance RF
absorption and/or emission of electromagnetic energy. NQR phenomena
may result, at least in part, due to the dependence of a portion of
the energy of electron-nuclear interactions on the mutual
orientations of asymmetrically distributed charges of the atomic
nucleus and the atomic shell electrons as well as those charges
that are outside the atomic radius. Thus, changes in the quadrupole
coupling constants and NQR frequencies may be due, at least in
part, to their electric origin. The nuclear electric quadrupole
moment eQ interacts with the electric field gradient eq, defined by
asymmetry parameter .eta.. Therefore, the nuclear quadrupole
coupling constant e.sup.2Qq and the asymmetry parameter .eta.,
which helps define structural information about a molecule, may be
calculated from the experimental data. The main spectral parameters
in the NQR experiments are the transition frequencies of the
nucleus and the line width .DELTA.f. Other parameters that may be
of interest include, for example, obtaining spin-lattice relaxation
time T.sub.1, spin-spin relaxation time T.sub.2 and line-shape
parameter T.sub.2* (inversely proportional to .DELTA.f). Any of
these parameters may affect the choice preferred a preferred
experimental technique and/or equipment.
[0028] Since the NQR frequencies depend on the molecular structure
of these substances they can be used for their practically unique
detection and identification.
[0029] In contrast to NMR methods, NQR can be performed without a
strong external static (DC) magnetic field. This technique may be
known as "pure NQR", or direct NQR detection, and may have many
advantages over other techniques, at least for some applications.
For example, direct NQR may be particularly useful for
identification of specific compounds and remote NQR detection. More
specifically, these methods may be particularly useful for
detecting the presence of specific substances, such as explosives
and/or narcotics, as well as landmine detection.
[0030] NMR exploits the interaction of nuclei with the magnetic
field. Therefore, a strong static field is generally applied to
polarize the nuclear magnetic moments. RF fields are used to
stimulate the spectroscopic response (NMR signal). A number of
minerals (e.g., copper minerals such as, for example, chalcopyrite
and cubanite) have a magnetically ordered structure. Thus, NMR can
be detected in their local field by means of a NQR technique
without applying an external static magnetic field. Therefore, in
various exemplary embodiments, both "pure NQR" and/or NMR in local
magnetic fields can be used for mineral analysis and exploration
including, for example, borehole logging applications.
[0031] Pulsed (including multi-pulse) techniques may be used in NMR
and/or NQR spectroscopy. These pulsed techniques may be used, for
example, to help increase sensitivity, reduce the experimental
time, and/or measure the relaxation time of the sample. In NQR and
NMR, single pulses may be used for detection of Free Induction
Decay (FID) signals and pulse sequences such as, for example, the
spin-echo (SE), Carr-Purcell (CP), Meiboom-Gill-modified CP (CPMG),
spin-locking spin-echo (SLSE) sequences and others. Pulse sequences
of the steady-state free precession type (SSFP), may be of
particular interest. An exemplary one of such sequences is well
known in the NQR art as the strong off-resonant comb (SORC).
[0032] The probe of a pulsed NQR (or NMR) detection system is
generally a device providing interaction between the radio
frequency (RF) field of a resonant RF transmitter and a particular
substance that is targeted within a sample for detection of NQR (or
NMR) signals generated as a result of the NQR (or NMR) phenomena,
as well as interaction between the RF field response from the
target substance and the receiving part of the NQR (or NMR)
detector. Strong RF pulses, typically with tens or hundreds of
watts of power, are used.
[0033] In an exemplary embodiment according to this invention,
there is provided a method for the mineral analysis of a sample
based on detecting NQR and/or NMR signals from a particular
substance that is targeted within the sample. In various exemplary
embodiments, the method has particular application to (but is not
limited to) the fields of mine site exploration and/or ore
delineation, such as for example bore-hole logging of ore
formations. In an exemplary embodiment, the method comprises:
[0034] (a) setting a frequency of the RF pulses to be approximately
equal to one of the nuclear quadrupole resonance or nuclear
magnetic resonance frequencies of the desired substance to be
analyzed; [0035] (b) setting at least one of the amplitude, phase,
duration, shape, number, repetition time and time between pulses of
the RF pulses to an optimal level that corresponds to the desired
substance to be analyzed; [0036] (c) setting at least one of the
gain, reference phase, acquisition time and acquisition number of
the receiver to an optimal level that corresponds to the desired
substance to be analyzed; [0037] (d) tuning the probe to provide
increased sensitivity for the signals detected at predetermined
frequency and/or to increase power transfer efficiency for RF
pulses transmitted with the probe; [0038] (e) transmitting the RF
pulses with the probe during a prescribed transmitting period to
irradiate the sample and excite an NQR and/or NMR signal in the
sample if the desired substance is present; [0039] (f) detecting
and processing NQR or NMR signals emitted by the presence of the
desired substance being analyzed [0040] (g) calculating the
concentration of the substance in the sample being analyzed [0041]
(h) repeating steps (a) to (g) for the next substance in the sample
being analyzed
[0042] In one exemplary embodiment, the method further includes
calibrating the probe for precise calculations of the concentration
of the desired substance in the sample being analyzed.
[0043] In one exemplary embodiment, the method further includes
measuring a temperature in or around the sample to adjust the
preset resonant frequency of RF pulses, parameters of RF pulses and
receiving parameters.
[0044] In one exemplary embodiment, the method further includes
applying a sequence of RF pulses (e.g., a pulse sequence) or
combination of pulse sequences chosen to correspond to the desired
substance to be analyzed.
[0045] In one exemplary embodiment, the pulse sequence is of the SE
or SLSE type.
[0046] In another exemplary embodiment, the pulse sequence may be
of the CPMG type.
[0047] In yet another exemplary embodiment, the pulse sequence may
be of the SSFP type.
[0048] In a different exemplary embodiment, the method may include
applying single pulses being chosen to correspond to the desired
substance to be analyzed.
[0049] In various exemplary embodiments, the method further
includes processing any received response signals to detect the
presence of an NQR and/or NMR signal corresponding to the desired
substance being targeted.
[0050] In various exemplary embodiments, the method further
includes measuring an intensity and line width of any received NQR
or NMR signals corresponding to the desired substance being
analyzed.
[0051] In various exemplary embodiments, the method further
includes measuring first and second relaxation times T1 and T2 if a
signal is received that indicates an NQR or NMR signal
corresponding to the desired substance being analyzed.
[0052] In various exemplary embodiments, the method further
includes calculating the concentration of each substance containing
the same element in the sample being analyzed.
[0053] In various exemplary embodiments, the method includes
calculating the total concentration of a chemical element in the
sample being analyzed.
[0054] In various exemplary embodiments of the present invention,
the method may include simultaneous detection of NQR or NMR in more
than one substance in the sample being analyzed.
[0055] In various exemplary embodiments of the present invention,
an apparatus for the mineral analysis and exploration using NQR
and/or NMR detection technique includes a probe, the probe
including a tank circuit with a coil system, a tuning and matching
circuit, and a Q-factor changing circuit; a transmitter, the
transmitter being usable to provide and/or apply RF pulses from an
output of the transmitter to the tank circuit; a receiver, the
receiver being tunable to at least one channel for detecting and
amplifying signals received in the coil system; and a processor for
processing the signals amplified by the receiver to help
distinguish the presence of any NQR and/or NMR signals
corresponding to a desired substance being targeted within the
sample, the processor may also be usable to calculate the
concentrations of the substance within the sample.
[0056] In various exemplary embodiments, the Q-factor changing
circuit is controllable to change a Q-factor of the tank circuit.
In various exemplary embodiments, the Q-factor of the tank circuit
may be adjusted to a desired level during a prescribed transmitting
period of an RF pulse for irradiating the sample with RF energy. In
various exemplary embodiments, the Q-factor of the tank circuit may
be adjusted to a minimal level during a prescribed recovery period
immediately following a transmitting period to rapidly dampen
transient signals from the probe.
[0057] In various exemplary embodiments, the Q-factor of the tank
circuit may be adjusted to a maximal level during a prescribed
receiving period for detecting an NQR and/or NMR signal from the
target substance, if present, immediately following the recovery
period.
[0058] In various exemplary embodiments, the probe may be usable
inside a borehole for borehole logging, and the coil system may be
designed to be usable for creating an RF field in, and receiving
signals from, a sample surrounding the probe.
[0059] In various other exemplary embodiments, the probe may be
designed to be usable for analyzing a sample when the sample is
placed into the probe. Likewise, the coil system may be designed to
be usable for creating and RF field and/or receiving signals inside
the probe.
[0060] In various other exemplary embodiments, the probe may be
designed to be usable for analyzing a sample when the sample is
placed at a desired distance from the probe. Likewise, the coil
system may be designed to be usable for creating an RF field in,
and receiving signals from, the sample outside the probe.
[0061] In various exemplary embodiments, the apparatus includes
measuring circuits and/or sensors for measuring a weight and volume
of the sample to be analyzed.
[0062] In various exemplary embodiments, the apparatus includes
measuring circuits and/or sensors for measuring a distance between
the probe and the sample to be analyzed.
[0063] In various exemplary embodiments, the probe includes one
tank circuit, the tank circuit including a coil system which can be
tuned to any desired NQR and/or NMR frequencies of the substances
to be analyzed.
[0064] In various other exemplary embodiments, the probe may
include several tank circuits, each tank circuit including a
separate coil systems which can be tuned to different NQR and/or
NMR frequencies of the substances to be analyzed.
[0065] In various exemplary embodiments, the coil system includes
one coil.
[0066] In various other exemplary embodiments, the coil system
includes more than one coil.
[0067] In various other exemplary embodiments, the probe includes a
temperature sensor for measuring the temperature inside and/or
around the probe to adjust the preset resonant frequency of RF
pulses.
[0068] These and other features and advantages of various exemplary
embodiments of systems and methods according to this invention are
described in, or are apparent from, the following detailed
descriptions of various exemplary embodiments of various devices,
structures and/or methods according to this invention.
BRIEF DESCRIPTION OF DRAWINGS
[0069] Various exemplary embodiments of the systems and methods
according to this invention will be described in detail, with
reference to the following figures, wherein:
[0070] FIG. 1 is a block diagram illustrating an apparatus for
mineral analysis and exploration, according to an exemplary
embodiment of the present invention.
[0071] FIG. 2 is a block diagram and borehole configuration of a
probe for mineral analysis and exploration, according to an
exemplary embodiment of the present invention.
[0072] FIG. 3 is a block diagram and volume configuration of a
probe for mineral analysis and exploration, according to an
exemplary embodiment of the present invention.
[0073] FIG. 4 is a block diagram and surface configuration of a
probe for mineral analysis and exploration, according to an
exemplary embodiment of the present invention.
[0074] FIG. 5 is a block diagram illustrating an apparatus with a
probe including a plurality of tank circuits for mineral analysis
and exploration, according to an exemplary embodiment of the
present invention
DETAILED DESCRIPTION
[0075] In various exemplary embodiments, the present invention is
directed toward a method and apparatus for mineral analysis and
exploration employing both NQR and NMR phenomena for detecting the
presence of and, if present, measuring a concentration of one or
more target (e.g., desired) substances containing quadrupolar
nuclei and nuclei with a magnetic moment within a sample.
[0076] Exemplary embodiments of the present invention will now be
described with reference to an apparatus for the mineral analysis
and exploration based on using both "pure NQR" and NMR in local
magnetic fields. However, it should be appreciated that various
exemplary embodiment of an apparatus and method according to the
present invention may be usable for other purposes. Further,
various exemplary embodiments may be advantageous over currently
used active nuclear techniques.
[0077] FIG. 1 is a block diagram illustrating an apparatus for
mineral analysis and exploration based on using "pure NQR" and NMR
in local magnetic fields, according to an exemplary embodiment of
the present invention. As shown in FIG. 1, a probe 40 is connected
to a receiver unit 50 and a transmitter unit 60. It should be
appreciated that the receiver unit 50 and the transmitter unit 60
may be any known or later-developed receiving and transmitting
devices (e.g., a conventional receiver and transmitter). The probe
40 includes a tank circuit 10, Q-switch unit 20 and a temperature
sensor (T-sensor) 30. The tank circuit 10 may be tuned to a
frequency of particular interest. The tank circuit 10 generally
includes a coil system, capacitors, tuning circuits and matching
circuits. The tank circuit 10 is connected to the receiver unit 50
and the transmitter unit 60.
[0078] The transmitter unit 60 generates RF pulses and transfers
these pulses to the probe 40 and the tank circuit 10. The pulses
are transmitted at a desired power, typically from tens of watts to
several hundred watts or even to several kilowatts. These RF pulses
can excite NQR or NMR signals in the sample under investigation
that is located within the bounds of the probe 40. This signal is
amplified and/or detected by the receiver unit 50 and is then
delivered for further mathematical processing into a control,
signal processing and calculating unit 70, one of the inputs of
which is connected to the output of the receiver unit 50. It should
be appreciated that the control, signal processing and calculating
unit 70 may be any known or later-developed processor such as, for
example, a microprocessor or microcontroller. After mathematical
processing, in the control, signal processing and calculating unit
70, the signal is used for further calculating of the substance
concentration in the sample being analyzed.
[0079] The control, signal processing and calculating unit 70
generates an RF signal, which is transmitted to one of the inputs
of the transmitter unit 60 for further formation of the RF carrier
for the RF pulses, and to one of the inputs of the receiver unit 50
to act as a reference frequency. The control, signal processing and
calculating unit 70 also generates signals to another input of the
transmitter unit 60 and prescribes parameters for the RF pulses and
the control signals, which are transmitted to the input of the
Q-switch unit 20 to change or control the Q-factor of the tank
circuit 10.
[0080] The Q-factor of the tank circuit 10 may be changed to an
first level during a prescribed transmitting period of an RF pulse
for irradiating the sample with said RF energy, a second level
during a prescribed recovery period immediately following said
transmitting period to rapidly dampen transient signals from the
probe and/or a third level during a prescribed receiving period for
detecting an NQR or NMR signal from the target substance if
present, immediately following the recovery period.
[0081] The T-sensor 30 measures the temperature of (or near) a
sample being analyzed. The signal generated by T-sensor 30 is
delivered into the control, signal processing and calculating unit
70, one of the inputs of which is connected to the output of the
T-sensor 30. According to the ambient temperature that is sensed by
T-sensor 30, the control, signal processing and calculating unit 70
adjusts the RF carrier to be close to one of the NQR frequencies of
the substance which is expected to be in the sample being
analyzed.
[0082] The control, signal-processing and calculating unit 70
usually consists of a computer, an RF signal source for producing
the RF pulses and electronic circuits for producing the control
signals.
[0083] Various exemplary embodiments of an apparatus and method
according to this invention may be particularly effective for the
detecting, identifying and/or measuring a concentration of
substances containing quadrupolar nuclei and/or nuclei with a
magnetic moment. Examples of such substances include, for example,
copper minerals such as different sulphides and oxides: CuS, Cu2S,
CuFeS2, CuFe2S3, Cu3SbS3, Cu3 BiS3, Cu2O and CuO. These substances
have been investigated, and strong NQR or NMR signals in the local
magnetic field have been obtained.
[0084] FIG. 2 shows an exemplary embodiment of the invention
directed toward an apparatus with an exemplary embodiment of a
probe that may be usable to borehole logging in mineral
exploration. This exemplary embodiment of the probe may be
particularly suitable for use in mining operations, in blast-holes
and exploration holes, both underground and open-pit
configurations.
[0085] As shown in FIG. 2 the probe 40, includes a tank circuit 10,
Q-switch unit 20 and a temperature sensor (T-sensor) 30. The probe
is connected to the receiver unit 50, the transmitter unit 60 and
the control, signal processing and calculating unit 70 (shown in
FIG. 1) by a cable 43. The tank circuit comprises a coil system 41
and supplied electronics 42 that include matching and tuning
circuits for matching and tuning to the predetermined resonance
frequency (equal or close to the RF carrier) of the substance to be
detected that exhibits NQR properties.
[0086] The coil system 41 is configured to provide optimal
excitation and detection NQR and/or NMR signals from the sample
surrounding the probe 10 as shown in FIG. 2. It should be
appreciated that the coil system 41 may include one, two or several
coils. Additionally, each coil of the coil system 41 may be a
single turn or multi-turn coil. Further, in various exemplary
embodiments, the Q-switch unit 20 and/or the temperature sensor
(T-sensor) 30 may be omitted.
[0087] FIG. 3 shows another exemplary embodiment according to this
invention, including another exemplary embodiment of the probe 40.
Similar to the embodiment shown in FIG. 2, the probe 40 includes a
tank circuit 10, a Q-switch unit 20 and a temperature sensor
(T-sensor) 30. Likewise, the tank circuit includes a coil system 41
and supplied electronics 42 that include matching and tuning
circuits.
[0088] In contrast to the embodiment shown in FIG. 2, the coil
system 41 shown in FIG. 3 is configured to be particularly useful
at providing excitation and/or detection of NQR and/or NMR signals
when the sample is placed inside the coil system 41. That is, the
coil system 41 is designed for "volume detection" of the sample. It
should be appreciated that, in various exemplary embodiments, the
coil system 41 may include one, two or several coils. Likewise,
each coil of the coil system 41 may be a single turn or multi-turn
coil.
[0089] It should also be appreciated that the exemplary embodiment
shown in FIG. 3 can be used both at a mine site and in the
laboratory. Further, in various exemplary embodiments, the Q-switch
unit 20 and/or the temperature sensor (T-sensor) 30 may be
omitted.
[0090] FIG. 4 shows yet another exemplary embodiment of a probe 40
according to this invention. The embodiment shown in FIG. 4 is
substantially the same as the embodiment shown in FIG. 3, except
that the coil system 41 is configured to be particularly useful at
providing excitation and detection of NQR and/or NMR signals from
the sample when the sample is placed a distance from the coil
system 41. That is, the coil system 41 is designed for "one side or
surface detection" of the sample. In this embodiment, the coil
system 41 includes at least one surface coil. It should be
appreciated that, in various exemplary embodiments, the Q-switch
unit 20 and/or the temperature sensor (T-sensor) 30 may be
omitted.
[0091] FIG. 5 shows a block diagram illustrating an exemplary
embodiment of an improved version of an apparatus for mineral
analysis and exploration based on using "pure NQR" and NMR in local
magnetic fields according to this invention. This embodiment shown
in FIG. 5 is very similar to the embodiment shown in FIG. 1, except
that the probe 40 comprises several (more than one) tank circuits
11, 12 . . . 1n. Each of the tank circuits is tuned to different
NQR or NMR frequencies (e.g., to frequencies that correspond to
different substances). This improved version of apparatus can be
used for simultaneous detection of different substances in the
sample to be analyzed.
[0092] This improved version of the apparatus may include any
version of the probe 10 described above with regard to FIGS.
2-4.
[0093] It should be appreciated that the scope of the present
invention is not limited to the particular embodiments described
herein, and that minor changes or variations to the elements may be
made that do not depart from the spirit of the invention and thus
remain within its scope.
[0094] It should also be appreciated that although the embodiments
have been specifically described for direct application using NQR
techniques, these embodiments are just as easily applied to NMR
using NMR techniques.
[0095] A method for the mineral analysis of a sample containing
substances with nuclei responsive to the Nuclear Quadrupole
Resonance (NQR) and/or Nuclear Magnetic Resonance (NMR) in local
magnetic field phenomenon, which comprises exciting, and detecting
NQR and/or NMR signals from a particular substance that is targeted
within the sample, measuring the intensity of any detected signal,
and calculating the concentration of the substance in the sample
being analyzed.
[0096] A method as in the preceding paragraph, and comprising the
following steps: [0097] (a) setting a frequency of the
radio-frequency (RF) pulses to be equal or near to one of the
nuclear quadrupole resonance or nuclear magnetic resonance
frequencies of the substance to be analyzed; and [0098] (b) setting
all parameters of the RF pulses: amplitude, phase, duration, shape,
number and repetition time or time between pulses to be optimal for
the substance to be analyzed; and [0099] (c) setting all receiving
parameters including (but not limited) the gain, reference phase,
acquisition time and acquisition number to be optimal for the
substance to be analyzed; and [0100] (d) transmitting the RF pulses
at optimal level during the prescribed transmitting period to
irradiate the sample and excite an NQR or NMR signal in the sample
if a substance providing for NQR or NMR is present; and [0101] (e)
detecting and processing NQR or NMR signals emitted by the
substance being analyzed; and [0102] (f) measuring the intensity of
NQR or NMR signals emitted by the substance being analyzed; and
[0103] (g) calculating the concentration of the substance in the
sample being analyzed; and [0104] (h) repeating steps (a) to (g)
for the next substance in the sample being analyzed.
[0105] The method may further include calibrating the probe for
precise calculations of the concentration of the substance in the
sample being analyzed.
[0106] The method may further include measuring a temperature of or
around the sample to adjust the preset resonant frequency of RF
pulses, parameters of the RF pulses and receiving parameters.
[0107] A method as in any of the preceding paragraphs, comprising
simultaneous detection NQR or NMR in more than one substance in the
sample being analyzed.
[0108] A method as in any of the preceding paragraphs, comprising
processing any received response signals to detect the presence of
an NQR or NMR signal corresponding to a substance being
targeted.
[0109] A method as in the preceding paragraph, comprising measuring
an intensity and line width of received an NQR or NMR signal
corresponding to a substance being analyzed.
[0110] A method as in the preceding paragraph, comprising measuring
relaxation times T1 and T2 if received signal is an NQR or NMR
signal corresponding to a substance being analyzed.
[0111] A method as in any the preceding paragraph, comprising
calculating the total concentration of the chemical element in the
sample being analyzed.
[0112] A method as in the preceding paragraph, comprising applying
a sequence of RF pulses (pulse sequence) or combination of pulse
sequences being applicable and optimal for the substance to be
analyzed.
[0113] The method may further include the pulse sequence being of
the SE or SLSE type.
[0114] Alternatively, the pulse sequence may be of the CPMG
type.
[0115] Likewise, the pulse sequence may be of the SSFP type.
[0116] A method as in any of the preceding paragraphs, further
comprising applying a single RF pulse being applicable and optimal
for the substance to be analyzed.
[0117] An apparatus for the mineral analysis of the sample
containing substances with nuclei responsive to the Nuclear
Quadrupole Resonance (NQR) and/or Nuclear Magnetic Resonance (NMR)
phenomenon, comprising: [0118] a probe comprising a tank circuit
with a coil system, tuning and matching means, and; [0119]
transmitting means for providing and applying powerful RF pulses at
the output thereof to the tank circuit; and [0120] receiving means
comprising at least one channel for detecting and amplifying
signals received in the coil system; and [0121] processing and
calculating means for processing the signals amplified by said
receiving means to distinguish the presence of any NQR or NMR
signals corresponding to a substance being targeted within the
sample and calculating the concentrations of said substance within
the sample; and [0122] calibrating means for precise calculations
of the concentration of the substance in the sample being analyzed
comprising at least one sample containing the substance with nuclei
responsive to the Nuclear Quadrupole Resonance (NQR) and/or Nuclear
Magnetic Resonance (NMR) in local magnetic field the concentration
of said substance in the sample is well known.
[0123] An apparatus as in the preceding paragraph, including
Q-factor changing means, wherein the Q-factor changing means is
controllable to change the Q-factor of the tank circuit to: [0124]
an optimal level during a prescribed transmitting period of an RF
pulse for irradiating the sample with said RF energy; [0125] a
minimal level during a prescribed recovery period immediately
following said transmitting period to rapidly dampen transient
signals from the probe; and [0126] a maximal level during a
prescribed receiving period for detecting an NQR or NMR signal from
the target substance if present, immediately following the recovery
period.
[0127] An apparatus as in any of the preceding paragraphs, wherein
the said probe comprises several tank circuits each of them is
tuned to different frequency according to NQR or NMR frequencies of
the substances to be analyzed.
[0128] An apparatus as in any of the preceding paragraphs, wherein
the said probe comprises at least one temperature sensor.
[0129] An apparatus as in any of the preceding paragraphs, wherein
the said coil system comprises one coil.
[0130] An apparatus as in any of the preceding paragraphs, wherein
the said coil system comprises more than one coil.
[0131] An apparatus as the preceding two paragraphs, wherein the
said probe designed to be used inside a borehole for borehole
logging, and the said coil system is designed to be optimal for
creating RF field in and receiving signals from the sample
surrounding the probe.
[0132] An apparatus as in any of the preceding paragraphs, wherein
the said probe designed for the sample analysis there the said
sample is placed into the probe, and the coil system is designed to
be optimal for creating RF field and receiving signals inside the
probe.
[0133] An apparatus as in any of the preceding paragraphs, wherein
the said probe designed for the sample analysis there the said
sample is placed at the some distance from the probe, and the coil
system is designed for one side detection to be optimal for
creating RF field in and receiving signals from the sample outside
the probe.
[0134] An apparatus as in the preceding two paragraphs, comprising
measuring means for measuring a weight and volume of the sample to
be analyzed.
[0135] An apparatus as in the preceding three paragraphs, comprises
measuring means for measuring a distance between the probe and the
sample to be analyzed.
[0136] Method and apparatus for the mineral analysis of the sample
based on detection NQR and/or NMR signals from a particular
substance that is targeted within a sample are disclosed. The
method comprises following steps: [0137] (a) setting a frequency of
the RF pulses to be equal or near to one of the nuclear quadrupole
resonance or nuclear magnetic resonance frequencies of the
substance to be analyzed; [0138] (b) setting all parameters of the
RF pulses: amplitude, phase, duration, shape, number and repetition
time or time between pulses to be optimal for the substance to be
analyzed; [0139] (c) setting all receiving parameters including
(but not limited) the gain, reference phase, acquisition time and
acquisition number to be optimal for the substance to be analyzed;
[0140] (d) tuning the probe to maximum sensitivity for the signals
detected at predetermined frequency and/or to maximum power
transfer efficiency for RF pulses transmitted with the probe;
[0141] (e) transmitting the RF pulses with the probe at said
optimal level during the prescribed transmitting period to
irradiate the sample and excite an NQR or NMR signal in the sample
if a substance providing for NQR or NMR is present; [0142] (f)
detecting and processing NQR or NMR signals emitted by the
substance being analyzed [0143] (g) calculating the concentration
of the substance in the sample being analyzed [0144] (h) repeating
steps (a) to (g) for the next substance in the sample being
analyzed.
[0145] The said method of the invention has particular application
to (but not limited to) the mine site exploration and ore
delineation including the bore-hole logging of ore formations.
* * * * *