Western Alaska Range

Cretaceous porphyry prospects along the Kahiltna Basin-Peninsula terrane boundary
Tract ID 003pCu5004
Country United States of America
Commodity Cu
Study area name United States revised - Alaska
Tectonic setting continental margin
Deposit type porphyry copper
Grade-tonnage model General porphyry copper model (Singer and others, 2008)
Geologic age
Geologic feature age Cretaceous
Generalized age Mesozoic
Oldest rocks age 145.5Ma
Youngest rocks age 65.5Ma
Age range 80Ma
Identified Cu resources 37,000,000metric tons
Known prospects 1
Mean Cu (t/sq km) 184t/sq km
Map scales used 250K

Results of the assessment

Assessment date 2012
Estimators Steve Ludington, Jane Hammarstrom, Gilpin Robinson, and 1996 Team
Assessment depth 1km
Quantitative assessment Yes

Estimated number of deposits

Number of deposits Confidence level
2 90%
5 50%
9 10%
15 5%
22 1%
Mean estimated deposits 5.83 ±4.63 (0.79%)
Probability of mean 0.29
Probability of no copper 0.04

Estimated deposit density

Known
deposits
Total
deposits
Area
(sq km)
Deposit density
per 100,000 sq km
1 6.83 125,156 5

Mean estimated tonnage

Copper 23,000,000
Molybdenum 640,000
Gold 560
Silver 7,500
Ore 4,600

Undiscovered copper resource

Confidence level 95% 90% 50% 10% 5%
Tonnage 250,000 1,400,000 12,000,000 56,000,000 87,000,000

Economic analysis

Fraser country US-Alaska
Fraser type 0.23%
Fraser high 0.76%
Typical cost 0%
High cost 1%
Infrastructure setting High cost
Comments on depth skew deep
Expected depth distribution
0 - 250m 0.2
250m - 500m 0.3
500m - 1km 0.5
Economically recoverable resources
Copper 11,000,000t
Molybdenum 240,000t
Gold 190t
Silver 3,500t
Probability no econ recoverable 0.49
Econ NPV 1,900x $1M
Exp dollars 9.57x $1M/100,000 sq km
Exp value class Low

Bibliographic references

General U.S. Geological Survey National Mineral Resource Assessment Team (2002)
Economic Robinson and Menzie (2012)

Deposits and prospects associated with this tract

Name Type State Country Development Details
Wells Mountain prospect Alaska United States Prospect Details
Bear Gulch prospect Alaska United States Prospect Details
Gold Hill prospect Alaska United States Prospect Details
Gull prospect Alaska United States Prospect Details
Gunsite prospect Alaska United States Prospect Details
Kamishak prospect Alaska United States Prospect Details
Kijik River prospect Alaska United States Occurrence Details
Lucky Strike prospect Alaska United States Prospect Details
Old Gold prospect Alaska United States Prospect Details
Ozzna Creek prospect Alaska United States Prospect Details
Pass prospect Alaska United States Prospect Details
Pebble deposit Alaska United States Prospect Details
Treasure Creek prospect Alaska United States Prospect Details
unnamed prospect Alaska United States Prospect Details
unnamed prospect Alaska United States Prospect Details
unnamed prospect Alaska United States Prospect Details
unnamed prospect Alaska United States Prospect Details
308 Zone prospect Alaska United States Prospect Details
38 Porphyry prospect Alaska United States Prospect Details