Rare Element Resources
Bear Lodge Project
Canadian NI 43-101 Technical Report
October 9
th
, 2014
10135-200-46 - Rev. 0
14-45
tonnage losses depends significantly on the cutoff grade. Dilution is about 15%, and
ore loss is 4% at a 1.5% TREO cutoff. When the cutoff grade is increased to 3.0%
TREO, dilution and ore losses increase to 22% dilution and 21% ore loss.
Table 14.26 - Dilution from Inverse-Distance-Power Estimation
Cutoff Grade =
1.5% TREO
Tons
Below
Cutoff
Metric
Tons
Below
Cutoff
Grade
Below
Cutoff
Tons
Above
Cutoff
Metric
Tons
Above
Cutoff
Grade
Above
Cutoff
%Dilution
/Loss
1
NN Model
51,569 46783
0.728
15,258
13842
3.438
IDP Model
48,935 44393
0.727
17,892
16231
3.075
Dilution
2,901
2632
1.114
19.0%
2
Ore-Grade Tonnage Lost
(267)
(242)
2.469
-1.8%
3
Net Dilution
2,634
2390
0.976
17.3%
Cutoff Grade =
3.0% TREO
Tons
Below
Cutoff
Metric
Tons
Below
Cutoff
Grade
Below
Cutoff
Tons
Above
Cutoff
Metric
Tons
Above
Cutoff
Grade
Above
Cutoff
%Dilution
/Loss
1
NN Model
60,298 54701
0.930
6,529
5923
5.190
IDP Model
60,019 54448
0.998
6,808
6176
4.514
Dilution
2,016
1829
1.965
30.9%
2
Ore-Grade Tonnage Lost
(1,737)
(1576)
4.095
-26.6%
3
Net Dilution
279
253
(11.285)
4.3%
1
- %Dilution/Loss computed relative to NN tonnage
2
- Dilution Grade is estimated as the average of the cutoff grade and the
NN grade below cutoff
3
- Ore Lost Grade is estimated as the average of the cutoff grade and the
NN grade above cutoff
(A.Noble, 2014)
Using a 1.5% TREO cutoff grade, overall dilution and ore losses from compositing
and smoothing to a 20-foot equivalent block size adds 57% dilution to tonnage at
about 0.9% TREO grade, and 11% ore is lost at 2.5% TREO grade. Thus dilution
and ore losses are fully accounted for in the resource model, and no further dilution is
needed for mine planning or scheduling.
It is noted that IDP dilution from volume-variance effects is significantly higher at a
3.0% TREO cutoff grade, and ore losses are much higher than at 1.5% cutoff grade.
