METHOD AND APPARATUS USABLE FOR MINING AND MINERAL EXPLORATION

• US 20110018535A1
• Filed: 07/23/2010
• Published: 01/27/2011
• Est. Priority Date: 07/27/2009
• Status: Active Grant

• Current Assignee: Lynxrail Corporation (Lynx Engineering Consultants Pty Ltd.)
• Original Assignee: Lynxrail Corporation (Lynx Engineering Consultants Pty Ltd.)
• Inventors: Rudakov, Taras
• Granted Patent: US 8,497,678 B2
• Time in Patent Office: Days
• US Class Current: 324/303
• CPC Class Codes: G01N 24/08 by using nuclear magnetic resonance G01N24/12 takes precedence
• CPC Class Codes: G01N 24/081 Making measurements of geologic samples, e.g. measurements of moisture, pH, porosity, permeability, tortuosity or viscosity
• CPC Class Codes: G01R 33/3808 Magnet assemblies for single-sided MR wherein the magnet assembly is located on one side of a subject only; Magnet assemblies for inside-out MR, e.g. for MR in a borehole or in a blood vessel, or magnet assemblies for fringe-field MR
• CPC Class Codes: G01R 33/441 Nuclear Quadrupole Resonance [NQR] Spectroscopy and Imaging
• CPC Class Codes: G01V 3/32 operating with electron or nuclear magnetic resonance

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.

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; and

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.

2. The method of claim 1, further comprising:

(a) setting a frequency of the RF pulses to be approximately equal to one of the NQR or NMR frequencies of the first desired substance;

(b) setting a set of parameters of the RF pulses to be optimal for the first desired substance;

(c) setting a set of receiving parameters to be optimal for the first desired substance;

(d) transmitting the RF pulses during a predetermined transmitting period to irradiate the sample and excite an NQR or NMR signal in the sample;

(e) detecting and processing any NQR or NMR signals emitted by an amount of the first desired substance;

(f) measuring the intensity of NQR or NMR signals emitted by the first desired substance;

(g) determining the concentration of the first desired substance in the sample being analyzed; and

(h) repeating steps (a) to (g) for a second desired substance in the sample being analyzed.

3. The method of claim 2, wherein:

the set of parameters of the RF pulses comprises;

amplitude, phase, duration, shape, number of pulses, and repetition or time between pulses; and

the set of receiving parameters comprises;

a gain, a reference phase, an acquisition time, and an acquisition number.

4. The method of claim 2, further comprising measuring a temperature of or around the sample and adjusting at least one of a preset resonant frequency of the RF pulses, at least one of the set of parameters of the RF pulses, and at least one of the receiving parameters based on the measured temperature.

5. The method of claim 1, further comprising simultaneously detecting NQR or NMR signals corresponding to more than one desired substance in the sample being analyzed.

6. The method of claim 1, further comprising receiving and processing at least one response signal to detect a presence of an NQR or NMR signal corresponding to the first desired substance.

7. The method of claim 6, further comprising measuring an intensity and line width of any received NQR or NMR signal corresponding to the first desired substance.

8. The method of claim 6, further comprising measuring a first and a second relaxation time of at least one response signal that is an NQR or NMR signal corresponding to the first desired substance.

9. The method of claim 1, further comprising determining the total concentration of at least one chemical element in the sample being analyzed.

10. The method of claim 1, wherein exciting and detecting NQR and/or NMR signals from an amount of the first desired substance within the sample using radio-frequency (RF) pulses comprises applying a sequence of RF pulses being applicable and optimal for the first desired substance.

11. The method of claim 10, wherein the sequence of RF pulses is selected from the group consisting of the SE, SLSE, CPMG, and SSFP type.

12. The method of claim 1, wherein exciting and detecting NQR and/or NMR signals from an amount of the first desired substance within the sample using radio frequency (RF) pulses comprises applying a single RF pulse being applicable and optimal for first desired substance.

13. An apparatus usable for mineral analysis of a sample containing at least one substance with nuclei responsive to a Nuclear Quadrupole Resonance (NQR) and/or Nuclear Magnetic Resonance (NMR) phenomenon, comprising:

a probe comprising a tank circuit with a coil system, tuning, and matching means;

transmitting means usable to provide and apply powerful radio-frequency (RF) pulses at an output thereof to the tank circuit;

receiving means comprising at least one channel for detecting and amplifying signals received in the coil system;

processing and determining means usable to process the signals amplified by said receiving means to help distinguish the presence of any NQR or NMR signals corresponding to a substance being targeted within the sample and determining a concentration of the substance being targeted within the sample; and

calibrating means usable to improve determinations of the concentration of the substance being targeted in the sample being analyzed, the calibrating means comprising at least one test sample containing a test substance with nuclei responsive to the Nuclear Quadrupole Resonance (NQR) and/or Nuclear Magnetic Resonance (NMR) in local magnetic field, the concentration of the test substance in the test sample being well known.

14. The apparatus of claim 13, further comprising Q-factor changing means, wherein the Q-factor changing means is controllable to change a Q-factor of the tank circuit to:

an optimal level during a predetermined transmitting period of an RF pulse for irradiating the sample with RF energy;

a minimal level during a predetermined recovery period immediately following said transmitting period to rapidly dampen transient signals from the probe; and

a maximal level during a predetermined receiving period for detecting an NQR or NMR signal from the substance being targeted immediately following the recovery period.

15. The apparatus of claim 13, wherein the probe comprises several tank circuits each being tuned to different frequencies corresponding to NQR or NMR frequencies of several substances to be analyzed.

16. The apparatus of claim 13, wherein the probe comprises at least one temperature sensor.

17. The apparatus of claim 13, wherein the coil system comprises at least one coil.

18. The apparatus of claim 13, wherein the probe is adapted to be usable inside a borehole for borehole logging, and the coil system is adapted to be optimal for creating RF field in and receiving signals from the sample surrounding the probe.

19. The apparatus of claim 13, wherein the probe is adapted for sample analysis with the sample placed within a housing of the probe, and the coil system is adapted to be optimal for creating an RF field and receiving signals within the housing of the probe.

20. The apparatus of claims 19, further comprising measuring means for measuring at least one of a weight and a volume of the sample to be analyzed.

21. The apparatus of claim 13, wherein the probe is adapted for sample analysis with the sample provided at a distance from the probe, and the coil system is adapted for one side detection to be optimal for creating RF field in and receiving signals from the sample outside the probe.

22. The apparatus of claims 21, further comprising measuring means for measuring a distance between the probe and the sample to be analyzed.