|
Cutoff |
CuEq% |
Metric |
Cu |
Au |
Mo |
Ag |
Re |
Cu |
Au |
Mo |
Ag |
Re |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Measured |
||||||||||||
|
0.3 |
0.65 |
527,000,000 |
0.33 |
0.35 |
178 |
1.7 |
0.32 |
3.83 |
5.93 |
0.21 |
28.1 |
167 |
|
0.4 |
0.66 |
508,000,000 |
0.34 |
0.36 |
180 |
1.7 |
0.32 |
3.81 |
5.88 |
0.20 |
27.4 |
163 |
|
0.6 |
0.77 |
279,000,000 |
0.40 |
0.42 |
203 |
1.8 |
0.36 |
2.46 |
3.77 |
0.12 |
16.5 |
100 |
|
1.0 |
1.16 |
28,000,000 |
0.62 |
0.62 |
302 |
2.3 |
0.52 |
0.38 |
0.56 |
0.02 |
2.0 |
14 |
|
Indicated |
||||||||||||
|
0.3 |
0.77 |
5,929,000,000 |
0.41 |
0.34 |
246 |
1.7 |
0.41 |
53.58 |
64.81 |
3.21 |
316.4 |
2,443 |
|
0.4 |
0.82 |
5,185,000,000 |
0.45 |
0.35 |
261 |
1.8 |
0.44 |
51.42 |
58.35 |
2.98 |
291.7 |
2,271 |
|
0.6 |
0.99 |
3,455,000,000 |
0.55 |
0.41 |
299 |
2.0 |
0.51 |
41.88 |
45.54 |
2.27 |
221.1 |
1,748 |
|
1.0 |
1.29 |
1,412,000,000 |
0.77 |
0.51 |
343 |
2.4 |
0.60 |
23.96 |
23.15 |
1.07 |
109.9 |
853 |
|
Measured + Indicated |
||||||||||||
|
0.3 |
0.76 |
6,456,000,000 |
0.40 |
0.34 |
240 |
1.7 |
0.41 |
56.92 |
70.57 |
3.42 |
344.6 |
2,615 |
|
0.4 |
0.81 |
5,693,000,000 |
0.44 |
0.35 |
253 |
1.8 |
0.43 |
55.21 |
64.06 |
3.18 |
320.3 |
2,431 |
|
0.6 |
0.97 |
3,734,000,000 |
0.54 |
0.41 |
291 |
2.0 |
0.50 |
44.44 |
49.22 |
2.40 |
237.7 |
1,848 |
|
1.0 |
1.29 |
1,440,000,000 |
0.76 |
0.51 |
342 |
2.4 |
0.60 |
24.12 |
23.61 |
1.08 |
112.0 |
867 |
|
Inferred |
||||||||||||
|
0.3 |
0.55 |
4,454,000,000 |
0.25 |
0.25 |
226 |
1.2 |
0.36 |
24.54 |
35.80 |
2.22 |
170.4 |
1,603 |
|
0.4 |
0.68 |
2,646,000,000 |
0.33 |
0.30 |
269 |
1.4 |
0.44 |
19.24 |
25.52 |
1.57 |
119.1 |
1,154 |
|
0.6 |
0.89 |
1,314,000,000 |
0.48 |
0.37 |
292 |
1.8 |
0.51 |
13.90 |
15.63 |
0.85 |
75.6 |
673 |
|
1.0 |
1.20 |
361,000,000 |
0.68 |
0.45 |
377 |
2.3 |
0.69 |
5.41 |
5.22 |
0.30 |
26.3 |
251 |
Notes:
David Gaunt, P.Geo., a qualified person as defined under 43-101 who is not independent of Northern Dynasty, is responsible for the August 2020 mineral resource estimate.
Copper equivalent (CuEQ) calculations use metal prices: US$1.85/lb for Cu, US$902/oz for Au and US$12.50/lb for Mo, and recoveries: 85% Cu, 69.6% Au, and 77.8% Mo (Pebble West zone) and 89.3% Cu, 76.8% Au, 83.7% Mo (Pebble East zone).
Contained metal calculations are based on 100% recoveries.
A 0.30% CuEQ cut-off is considered to be appropriate for porphyry deposit open pit mining operations in the Americas.
The mineral resource estimate is constrained by a conceptual pit shell that was developed using a Lerchs-Grossman algorithm and is based in the following parameters: 42 degree pit slope; metal prices and recoveries of US$1,540.00/oz and 61% Au, US$3.63/lb and 91% Cu, US$20.00/oz and 67% Ag and US$12.36/lb and 81% Mo, respectively; a mining cost of US$1.01/ton with a US$0.03/ton/bench increment and other costs (including processing, G&A and transport) of US$6.74/ton.
All mineral resource estimates, cut-offs and metallurgical recoveries are subject to change as a consequence of more detailed analyses that would be required in pre-feasibility and feasibility studies.
