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?Dave,

Attached are the XRF shots of the two? Mt Pass Bastnasite samples you sent me

The large sample (#1) that had the galena stringer in it was shot on both sides as well as the "sparkly" stringer which, as you guessed, is Galena - PbS. See the Eckhart log file for the positive ID picks, other elements in the shot files are not verified due to peak over lap or no confirming Kb or Lb peak. The percentages are higher than actual as the calibrate that was used was for ppm level elements which will over report percentages in this mode.

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Bastnasite is (Ce,La)CO3F and in this case is hosted in a Carbonatite which is an igneous sourced rock with predominantly carbonate minerals but also having the siliceous , oxide, and phosphate type mineralization

In these samples we see Ca S, P,? Fe, Sr, and Ba dominating. For the rare earth elements Ce and La, dominate but Nd, Pr and some Nb are also seen.? The P is most probably due to apatite or some monazite. Surprisingly the U and Th content is below the detection level and that was unexpected as my prospecting around the Mt pass complex has shown high Th with some U.

I suspect the high Sr and Ba are from Barite (Ba, Sr) SO4 while the Fe and S are due to pyrite FeS2

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The highest Ce is found in the large #1 galena stringer sample at 1.8% Ce with La at 1.2%. The Galena stringer has a Pb content of 10.6% with 11 ppm Cd. Cd is commonly associated with Galena.? In general the Pb in the other samples are much lower. The small sample # 2 had a 1.1% Pb content and had what looked like an oxidized galena coating under the microscope.

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I also included a shot of "Mt Pass MolyCorp White Earth Concentrate" that was in a 5 gallon bucket I sub sampled from a company going out of business.

While it said "White Earth? Concentrate" it is actually a dark grey powder. Its elemental composition is predominantly Ti and Ca. The Ba and Sr are low in the 100's of ppm and its slightly radioactive with Th at 239 ppm.? Nb is at 2602 ,Nd 3138, Pr 819, Ce 7136, La 2973 and Zr at 803 ppm. Quite a bit different than the actual rocks.

This was a nice host rock sample set showing what the actual carbonatite looks like rather than running a crystal of just bastnasite which one usually gets.

Dud KK7IF

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