Re: Virgin Lead

[ILPreiss@aol.com]

NL Industries, when they were called National Lead, did indeed supply two
types of "virgin" lead. The common , and least expensive form was radiogenic.
That is it contained "trace" amounts of 210-Pb and other decay products,
including, if you looked hard enough, fission fragments. The source of ore
was from regions such as Colorodo and New York where the formations were high
in natural uranium. 

The non-radiogenic lead was generally older (maybe 100 years) and had its ore
source in Spain or other geolical formations not associated with U deposits
as well.

Low background counting systems I contructed to define natural radioactive
materials as far back as 1957 were shielded using the latter, obviously. I
would gues that the "contaminated lead" has been around for an awful long
time. We simply never had reliable enough low level counting gear as survey
instruments to see it, or didn't care since the regs didn't know about it
either.

Preiss