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7/29/2019 Radiometric Surveying- Final.pptx
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Surveying for the acquisition of radioactive
minerals, using their radioactive properties of
radiation emission.
Radiometric Surveying
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Characteristics:•Shallow method.
•Success rate depends upon rock
exposure (99% gamma radiations areattenuated by 35-40 cm of soil)
•Survey planning is the same as gravity
and magnetic method.
Radiometric Surveying
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Air-borne Radiometric Surveying
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Air-borne Radiometric Surveying
•These are done before pursuing a groundradiometric survey.
• Scintillation counters or gamma-ray detectors are
mounted on an aircraft flying 80m above theground.
• Flight lines are spaced 1-5 km apart forreconnaissance surveys and 250 - 5000 m fordetailed surveys.
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Radiometric Airborne Surveying
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Air-borne Radiometric Surveying
•The helicopter flies at speeds of 50 m/s (90knots), recording a sample every 30-60 m alongthe flight path.
•
These anomalies are later used for ground follow-up surveys .
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Ground Radiometric Surveying
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Ground Radiometric Surveying
• Once an anomaly is identified using airborne
methods, a hand-held or jeep mounted
scintillometer or GM counter is used for detail
surveys.• The most common procedure is to walk over the
terrain while listening to the counts on
earphones or watching the dial of the counter.
• Ground radiometric surveys are most effective
where rock exposures are available.
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Ground Radiometric Surveying
Radiometric ground surveying
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• This spectrum has peaks corresponding to the
presence of potassium, thorium and uranium. The
heights of the peaks relate to the number of
gamma rays recorded (in counts per second), and
the horizontal axis relates to the energy of the
gamma rays (high energy at left and low energy at
right).
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Exploratory drilling
• Once an anomaly has been deciphered with
a fair level of confidence, it is explored by
drilling.
• The borehole samples are then studied in
the lab to determine the ore mineralogy.
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Applications of Radioactive
method
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Applications of Radioactive
method• Exploration of radioactive minerals.
• Exploration of petroleum.
• Delineating Faults and Fractures: Radon leakage.
• Geological mapping.
• Useful in Agriculture: in mapping different soiltypes.
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Applications of Radioactive
method• Monitoring the natural radioactivity at reactor
sites.
•
Identification of radioactive industrial waste.
• Assessment of slope stability (which are oftenassociated with fractures and groundwater flow) .
• Contamination in soil from leakage from nuclearreactors.
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Advantages of Radioactive
method
• Only method by which radioactive mineral
exploration can be done accurately.
• Easy method.
• Has a lot of applications apart from
exploration of radioactive minerals
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Disadvantages of Radioactive
method
• Shallow method.
• Cannot be applied for anomalies below 35-
40 cm of soil.
• Does not tell us the specifications of
anomaly.
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