nt for uranium exploration

8/10/2019 NT for Uranium Exploration

1/50


2/50

Nuclear TechniquesUranium ExploratioSUBMITTED TO:

DR. ABID


3/50

Group Members

Name Registration No.

Ali Ammar MSPE-1323

Arslan Arshad MSPE-1333

Ahtisham Arshad MSPE-1332

Muhammad Mujahid MSPE-1328


4/50

Synopsis

Exploration

Objectives of Exploration

Exploration Techniques

Nuclear Techniques

Gamma Survey

Radon Survey

Neutron Activation

Delayed Neutron Counting


5/50

Exploration

AnalysisQuantity

Quality

Several exploration techniques are used, dependingtype of deposit and its proximity to the surface.


6/50

Objectives of ExplorationEstablish baseline/background conditions

Find alteration zones

Find ore body

Determine if ore can be mined or leached

Determine if ore can be processed

Determine ore reserves

Locate areas for infrastructure/operations

Environmental assessment

Further understand uranium deposits

Refine exploration models


7/50


8/50

Exploration Steps

Area SelectionReconnaissance

phaseFollow up Phase Detailed Phase

Locate area ofinterest

Locate exactly on theground the extent

anomalies in area ofinterest


9/50

Fundamental Parameters

Physical Properties

Form of Mineralization

Accumulation in Host Rock

Abundance

Age of Rock


10/50

Uranium as Mineral Deposit

Uranium (U) has an average crustal abundance of 23 ppm

Minerals with uranium as a major constituent include uraninite (pitcbetafite, coffinite and several others

While those with uranium as a minor constituent include zircon, xenmonazite, orthite, apatite, and sphene

Uranium has three radioactive isotopes 238U (99.274%, T1/2= 4.5 1235U (0.720%, T1/2= 7.13 10

8years) and 234U(0.006%)


11/50

Physical Properties


12/50

Exploration TechniquesMagnetic Surveys

Electromagnetic (EM, EMI), Electromagnetic Sounding

Direct Current (DC)

GPR (Ground penetrating radar potential)

Seismic

Time-Domain Electromagnetic (TEM)

Controlled source audio-Magnetotellurics (CSAMT)

Radiometric Surveys

Induced Polarization (IP)


13/50

Exploration Techniques (Contd..

Spontaneous potential (SP)

Borehole geophysics

Satellite imagery

Imagery spectrometry

ASTER (Advanced space-borne thermal emissions reflection radiometer)

Multispectral


14/50

Exploration Techniques

Radiometric SurveysGamma Survey

Radon Survey

Analytical Techniques

Neutron Activation

Delayed Neutron Counting

X-ray Fluorescence Analysis

Fluorometry

Spectrophotometry

Gravimetric and Volumetric Analysis


15/50

Radioactivity

The atomic nuclei of some isotopes are unstable, disintegrate and form a neaccompanied by emission of particles or energy, termed nuclear radiation.

Nuclides with this feature are called radionuclides.

The radioactivity decay law expresses the decrease in the original number oof a radionuclide with time (t)

Nt= Noet


16/50

Measurement and Units


17/50

Nuclear Radiation and Interactio

Potassium, uranium and thorium are naturally occurring radioactive elemenabundance in the rocks throughout the world. The emitted radiation of therelatively intense and easily measured in the field.

Alpha Radiation (positively charged alpha particles of relatively great mas

Beta Radiation (electrons)

Gamma Radiation (electromagnetic, and its rays are specific for a particu Photoelectric Effect

Compton Scattering

Pair Production


18/50

Gamma SurveyThe most important elements contained in crustal rocks that make up the bmeasurable terrestrial gamma radiation are potassium, uranium and thoriu

The total measured radiation can be represented by the equation

Itotal= Irocks+ Icosm+ Iradon+ ICs

Irocks = Radiation due to rocks

Icosm = Cosmic rays

Iradon = Radiation due to atmospheric radon

ICs = Radiation due to Cesium (Areas which are influenced by Fallout)


19/50


20/50

Gamma Survey (Contd..)

Gamma radiation of a point source (small geological object) with a radioelem, is reduced by the square of the sourcedetector distance r (m), and attethe mass of environment of this path; attenuation for given energy of gammspecified by the linear attenuation coefficient (m-1).

I = (km/r2) * e-r

where k is the constant expressing gamma radiation of a particular radionuc


21/50


Environmental factors that can significantly affect observed gamma ray fielWeathering Overburden

Dense Vegetation

Increase in Soil Moisture

Weathering overburden will attenuate the gamma radiation, dense v

cause the reduction in the gamma radiation and the last will also reducradiation and the measured radiation will be much lesser than the original


22/50


Gamma ray surveying is conducted as a total count survey or gamma ray spTotal count surveys (TC) with scintillation count rate meters are applied to gmeasurements and to borehole logging. The relationship between the recorate, nTC(counts/s), and the concentration of K, U, and Thorium in the grou

nTC= SKCK+ SUCU+ SThCTh

where SK, SU, SThare the sensitivities of the TC instruments (counts/s per uconcentration of relevant radionuclide), and CK, CU, and CThare radioelemeconcentrations.


23/50


Airborne gamma ray spectrometry has been used over many years for uranexploration and spectrometers have scintillation detectors.

Car-borne gamma ray spectrometry is another platform for surveying and in car-accessible terrain. A car-borne multichannel gamma ray spectrometehas a NaI(Tl) scintillation detector.

Gamma logging in boreholes involves a TC technique or gamma ray spectro

NaI(Tl) or CsI(Tl) scintillation crystals installed in the logging probe have limiand therefore limited size.


24/50

Gamma Survey (Contd..)Scintillators:

The operation of a scintillation counter may be divided into two broad steps:

Absorption of incident radiation energy by the scintillator and production of photovisible part of the electromagnetic spectrum

Amplification of the light by the photomultiplier tube and production of the outpu


25/50

Scintillators


26/50


27/50

Gamma Survey (Contd..)Solid State Detectors:

The term solid state detectors refers to certain classes of crystalline substwhich exhibit measurable effects when exposed to radiation.

Difference in energy produced by excitation and de-excitation of electronsthe fluorescent radiations.


28/50

Gamma Survey (Contd..)The Geiger Muller Counter:

It is based on the ionization of gas in chamber which is connected to anodcathode.

The flow of the ions produces the current which the measure of incident r


29/50

Geiger Muller Counter


30/50

Radon Survey

Originated from the decay of uraniumUsed as an indicator and is a source of alpha radiations

Uranium ore body exhibit radon activity concentration of the order of 10decreases with distance

Activity Concentration of Radon

CA= am* * kem/p

Radon (222Rn) activity concentration cA(Bq/m3) in soil gas, mass activity amo

(Bq/kg), density of the rock (kg/m3), emanation power kemand rock poros


31/50

Radon Survey (Contd..)Radon Movement is due to:

Diffusion

Convection

Diffusion depends on the diffusion coefficient of the soil and the radon decay const

CAx= CA0e-x/D

Convection is caused by:

Underground Water

Temperature Gradient

Pressure and Tidal Effects


32/50


33/50

Radon Survey (Contd..)

Emanometers:

These are the radon detectors which measure the alpha activity of the soi

Sample is placed in ionization chamber where the alpha particles are releadisintegration of radon

These Particles are then counted and registered


34/50


35/50

Flow Path


36/50


Alpha Track Methods:

Based on the registration of radon alpha particles on the sensitive film

Cups with sensitive film are placed in pits covered by soils left for 20-30 d

Density of alpha tracks recorded on the film is a measure of radon in soil g


37/50


Alpha Card Method:

Alpha card is a paper frame with a circular, aluminum-coated Mylar collect

It detects the radioactivity of radon solid products as they accumulate on placed in the pit for 1-2 days


38/50


The Radon on Activated Charcoal (ROAC):

This method is based on the adsorption of radon gas on activated charcoa

Charcoal in a plastic container is placed into a pit for an exposure period odays.

The gamma radiation of radon decay products balanced with the quantityradon on activated charcoal is counted.


39/50

ROAC Kit


40/50

Radon Detection


41/50

Neutron Activation

A useful, sensitive and accurate method used for uranium is neutron activanalysis.

It can be carried out by any source of thermal neutrons, but usually requirreactor.

An atom of 238U captures the neutron and converted into 239U which in turbeta emission with half life of 23.5 minutes to 239Np

In turn 239Np decaying by beta emission having half life of 2.36 days conve239U. Which can be used to determine the quantity of uranium in the sampl


42/50

Neutron Activation


43/50


44/50

Seismic Imaging

Estimates the seismic characteristics of the Earthssurface.

Acoustic energy waves are sent

Every mineral has different hardness, density, and porosity.

Intensity & time of reflected sound is measured.

How long it took to receive reflected sound wave. This data

tells where rock properties changes.

Reflected acoustic energy waves are measured. Vibrators or detonators are used for sound waves.


45/50

Seismic Imaging


46/50

Magnetic ImagingMagnetic field characteristics measured.

Minerals have distinct & different intensity magneticfields.

Magnetometer is mounted on an operator or on aeroplane or helicopter.

Magnetic surveys can be done on ground or aerially.


47/50

Magnetic Imaging


48/50

Gravity MethodMeasurements of the gravitational field at a series

of different locations over an area of interest. Theobjective in exploration work is to associate variationswith differences in the distribution of densities andhence rock types.

Dense and heavy rocks, due to their extragravitational attraction increases the downward pulland creates positive gravity anomalies (gravity

highs).

Where the rocks are light, the gravitational pull isdiminished and the anomalies are negative (gravitylows).


49/50

Geological Mapping (Results)

A way to gather & present geologic data.

By assembling different ground radiationdatasets a dose rate map of Uranium could beconstructed.

Shows how rock & soil on the earths surfaceis distributed.

Help to come up with a model for an orebody.

Show other features such as faults and strikeand dips.


50/50

THANK YOU

nt for uranium exploration

Documents