Re: U to Th ratio in Columbium ores

[sbrightwell@shepmill.com (Shane Brightwell)]

I queried our scientists and got this response:

	Shane,

	I only spent about 10 minutes on the www (Google was
	the best at finding references) looking for
	Columbite and tantalite chemical data.  It was obvious 
	that there is quite a variety of substitution metals 
	in the basic formula (Fe++, Mn)(Nb,Ta)O6 .  The 
	ratios of U to Th were not given.  Wouldn't they
	vary depending on the age of the deposit due to decay?
	And if the system isn't "closed", they would possibly
	be in disequilibrium.

	 A variety of deposit ages were noted.  Also columbite
	 and tantalite actually comprise a series of minerals 
	with differing amounts of metal substitutions - so 
	asking the question of how much uranium in the ore 
	may mean which deposit, what part of that deposit. 
	Some deposits were in pegmatites (Colorado, Australia), 
	others were in Virginia, Rwanda, Argentina, Canada, Finland. 

	Good luck,

	Dave Bauer


At 12:31 PM 08/31/1999 -0500, you wrote:
>Hi Radsafers
>I'm looking for information on the uranium to thorium ratios in columbium 
>(columbite) and tantalite ores.  If anyone can help out or steer me in the 
>right direction I would be grateful.
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