Rare Element Resources
Bear Lodge Project
Canadian NI 43-101 Technical Report
October 9
th
, 2014
10135-200-46 - Rev. 0
14-9
Table 14.6 - Method for Measuring and Calculating Density
1
A sample of intact core was selected such that the core was unbroken and contained only one
lithology and oxidation type. Thus, oxide FMR samples were only oxide FMR, and oxide wall-
rock samples were only oxidized wall rock. Samples averaged approximately 1kg, but ranged
from 0.23 kg to 2.26 kg.
2
The sample was vacuum-sealed in a plastic wrapper. The wrapped sample was weighed on a
digital balance with a resolution of 1 g and an accuracy of 2 g. This weight is
ܹ
ௐோா
.
3
The wrapped sample was weighed again while submerged in water using the same digital
balance. This weight is
ܹ
ௐ்ாோ
.
4
The sample was unwrapped and weighed without the wrapper. This weight is
ܹ
ூோ
.
5
The sample was dried for 22 to 48 hours in a 90°C oven.
6
The dried sample was weighed. This weight is
ܹ
ோ
.
7
Sample dry density is computed as follows:
a. The weight and volume of the plastic wrapper is computed:
ܹ
ௐோாோ
= ܹ
ௐோா
− ܹ
ூோ
ܸ
ௐோாோ
= ܹ
ௐோாோ
ߜ
ௐோாோ
ൗ
Where
ߜ
ௐோாோ
is the density of the wrapper (0.8 g/cc for FoodSaver 8” rolls)
b. The volume of the sample is computed:
ܸ
ௌொ
= ܹ
ௐோா
−ܹ
ௐ்ாோ
− ܸ
ௐோாோ
c. The dry density of the sample is computed:
ߜ
ௌொ
= ܹ
ோ
ܸ
ௌொ
ൗ
d. The moisture content of the original sample is computed:
ܯ%
݅
ݎݑݐݏ
݁ = 100 × (ܹ
ூோ
− ܹ
ோ
) ܹ
ூோ
ൗ
(Noble et al 2013)
This density measurement procedure works very well for difficult samples, such as
vuggy/porous samples, samples with high clay content, and samples with poor
cohesiveness. A point of caution is that the sample must not be broken or highly
irregular, or the wrapper will not fit tightly to the sample, leaving gaps that cause the
measured density to be too low. In addition, the accuracy of this procedure drops
dramatically as the weight of the sample goes down. For example, when using an
electronic balance with an accuracy of +/-2 grams (0.07 ounce), the measuring
