technical report on the nechalacho deposit, thor lake project ...

Tb and Dy) were routinely monitored along with the overall values for the total rare earths
(TREE) and heavy rare earths (HREE).
Precision results of the QAQC program for all labs, as measured by relative standard deviation
(standard deviation/sample population mean) for, as an example standard AVL-H (also referred
to as STD-H), average between 3.5% and 5.7% for all rare earth elements, Nb, Ta and Zr. The
results for the largest groups of analyses, representing 524 analyses of the standard, are listed
in Table 14-2).
Table 14-2 Relative Standard Deviations, Standard AVL-H (2007-2010)
Samp_type Method Lab N Y %SD La %SD Ce %SD Pr %SD Nd%SD Sm %SD Eu %SD Gd %SD Tb %SD
AVL-H MS81h ALS 224 3.6% 3.6% 3.6% 4.1% 3.8% 3.7% 3.8% 3.7% 4.6%
STD-H 4A-4B Acme 89 7.1% 6.6% 7.1% 6.0% 5.4% 5.0% 6.0% 7.9% 6.2%
STD-H MS81 ALS 112 5.1% 5.3% 4.9% 5.5% 5.7% 5.6% 5.2% 5.8% 5.8%
STD-H MS81H ALS 99 3.7% 4.7% 4.6% 4.4% 4.1% 4.3% 4.1% 4.2% 4.8%
Samp_type Method Lab N Dy %SD Ho %SD Er %SD Tm %SD Yb %SD Lu %SD Nb %SD Ta %SD Zr %SD
AVL-H MS81h ALS 224 3.9% 4.6% 4.5% 4.4% 4.1% 4.8% 4.0% 4.2% 4.1%
STD-H 4A-4B Acme 89 5.4% 6.3% 5.5% 6.1% 5.5% 6.3% 6.7% 7.5% 5.9%
STD-H MS81 ALS 112 5.1% 5.7% 5.0% 5.6% 5.3% 5.4% 6.7% 7.4% 15.6%
STD-H MS81H ALS 99 3.4% 4.1% 5.0% 4.5% 4.7% 4.4% 5.9% 5.5% 4.4%
The results indicate that AVL-H/STD-H (same standard but inserted with different designation in
the drill logs) are basically identical in relative SD and that Acme’s analyses show about 50%
higher relative standard deviation than MS81H method of ALS. The latter laboratory’s MS81
method shows slightly higher relative SD compared to MS81H. However, as the laboratories
anticipate 10% relative standard deviation, all are within acceptable limits.
Thus it is concluded that the precision results of both laboratories are within acceptable limits for
analyses from 2007 to 2010.
Table 14-3 gives the calculated comparison of the means of the particular set of analyses of
STD-H expressed as percentage of the overall mean of all analyses of that standard from 2007-
2010. The total analyses, including those in Round Robin campaigns and routine batches,
include at least eight laboratories and methods for the rare earths. Comparison of 112 analyses
by MS81 (ALS), 323 analyses by MS81H (ALS) and 102 analyses by method 4A/B (Acme)
indicate that the average differences are 101%, 99% and 95% respectively. Thus ALS results
are very close to the mean of all labs, and Acme son average about 5% lower than all
laboratories.
Technical Report 43-101 – March 13, 2011 Page 14-2
Prepared by Avalon Rare Metals Inc.