Donald G. Hill, Ph.D., 

R.Gp., R.G., R.P.G.

Consulting Petrophysicist

"The World is my District"


California Registered Geophysicist No. 170

California Registered Geologist No. 6043

Kentucky Registered Professional Geologist No. 1624

Texas Licensed Professional Geophysicist No. 6289


Density Log Contamination by High-Yield Uranium Ore Gamma Radiation 



This particular property was a candidate for in-situ leach mining.  Mine design required accurate estimates of porosity in the ore zone, which were estimated from density/neutron cross-plots.  Density log gamma ray sources are usually strong enough and of high enough energy that the detector count rates are not effected by variations in radio active mineral concentrations. 

The above example is from a slim-hole density log in very high grade (approximately 2 % uranium oxide, by weight) uranium ore zones.  The density log, shown in Track 3, has apparent density lows corresponding to depths of high gamma radiation (count rates approaching 2400 cps).  Because of the high ore grade radioactivity, a density log natural radioactivity correction was developed.  Track 3 also shows the natural radioactivity corrected density log.  The difference between the original and corrected density log curve (as much as 0.45 - 0.50 gm/cc) is shaded.

Use of this density log natural radioactivity correction allowed the mine planning to proceed with confidence.  

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Contact:  Donald G. Hill at: Cell/Business Phone:  +(925) 437-5748,   FAX:   +(309) 420-7354,   Home Phone:  +(925) 947-1541  


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