[ RadSafe ] Re: DU Cleanup

[Dan W McCarn]

Dear Joel:

The estimates for U concentrations vary from very little to lots depending
on whether you are near one of the phosphorites that are all over the Middle
East (parts of Iraq, Jordan, Israel, Palestine, all the way to Morocco.
Morocco has historically supplied phosphate ores (0.125% U; 125 mg/kg) all
over the world and they are very similar to Florida, USA phosphate ores.
Jordan (I believe) has phosphate production as well. These "I believe" are
the most significant uranium occurrences in the Middle East.

I lump marine phosphorites and black shales together because during
deposition, they both adsorb large quantities of uranium from circulating
seawater as they are being deposited.  Since seawater has a fairly uniform
concentration of uranium, all phosphorites and black shales have about the
same uranium concentrations worldwide.  They both have a high Kd for U.
Average seawater concentration is about 3.3 ug/L. And it doesn't seem to
matter if it was a Cretaceous Sea or a Devonian Sea, they are all similar.

So get a geological map, look at the outcrops around, and if you see marine
black shales or phosphorites, you can pretty well bet that it will have
significantly elevated uranium concentrations.

Fully loaded extraction cost for commercial by-product uranium using the wet
phosphoric acid process is about $25/lb U3O8 (current price of uranium is
over $40/lb U3O8).  The marginal cost is about $15/lb U3O8 if you don't care
about capital cost recovery.

I would estimate that 1/4 of the USA is underlain by exposures of marine
black shales or phosphorites and includes the Chattanooga Shale (Alabama &
Tennessee), Pierre Shale (mid-continent), Phosphoria FM, and several
cretaceous shales whose name escapes me.  The Kolm Shale in Sweden also
comes to mind.

Dan ii

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
Of cehn at aol.com
Sent: Wednesday, September 20, 2006 15:29
To: radsafe at radlab.nl
Subject: [ RadSafe ] Re: DU Cleanup

 Dan's calculation is interesting.  I have a limited amount of data on
natural U-238 in Kuwaiti desert sand (less than 2 pCi/g).  This is quite
close to the 5 mg/Kg that he uses.  Does anyone have good data on background
concentrations in Middle East/Persian Gulf region sand?
 
--Joel I. Cehn, CHP
joelc at alum.wpi.edu
 
 
-----Original Message-----



Dear Group:  This is what I intended to send....  Sorry that the table got
decomposed.

   Estimated Natural Uranium Endowment in a Typical Backyard -  5 mg/Kg U
======Soil Volume========  ========Soil Weight========= ==U Endowment==
  X     Y      Z     Vol    Bulk Density Tonnes   Kg     Percent   U
  m     m      m     m^3       g/cc      Soil    Soil       U      Kg
 20.0  20.0  0.25   100.0      1.50       150   150,000  0.0005%  0.75


  Estimated Natural Uranium Endowment in Soils Overlying Black Shales or
Phosphorites -  125 mg/Kg - e.g. Chattanooga Shale, USA;  Kolm Shale, Sweden
======Soil Volume========  ========Soil Weight======== ===U Endowment==
  X     Y      Z     Vol   Bulk Density Tonnes   Kg     Percent    U
  m     m      m     m^3      g/cc       Soil   Soil       U       Kg
 20.0  20.0  0.25   100.0     1.50       150   150,000  0.0125%   18.75

Dan ii

Dan W. McCarn, Geologist