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Eastern Alaska Range and Wrangell Mountains

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Cretaceous (115-105Ma) deposits and prospects along the Nutzotin Basin-Wrangellia terrane boundary; south of the Denali Fault
Tract ID 003pCu5002
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 Canadian Cordillera Porphyry Cu±Mo±Au (Frost and others, 2011)
Geologic age
Geologic feature age Jurassic through Cretaceous
Generalized age Mesozoic
Oldest rocks age 199.6Ma
Youngest rocks age 65.5Ma
Age range 134.1Ma
Identified Cu resources 3,000,000metric tons
Mean Cu (t/sq km) 557t/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
4 90%
15 50%
30 10%
30 5%
30 1%
Mean estimated deposits 15.93 ±9.15 (0.57%)
Probability of mean 0.46
Probability of no copper 0.02

Estimated deposit density

Known
deposits		 Total
deposits		 Area
(sq km)		 Deposit density
per 100,000 sq km
5 20.93 37,680 56

Mean estimated tonnage

Copper 21,000,000
Molybdenum 870,000
Gold 1,100
Silver 7,300
Ore 7,700

Undiscovered copper resource

Confidence level 95% 90% 50% 10% 5%
Tonnage 1,400,000 3,500,000 19,000,000 41,000,000 47,000,000

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 0.1
250m - 500m 0.3
500m - 1km 0.6
Economically recoverable resources
Copper 480,000t
Molybdenum 11,000t
Gold 1t
Silver 92t
Probability no econ recoverable 0.96
Econ NPV 34x $1M
Exp dollars -87.97x $1M/100,000 sq km
Exp value class Very Low

Bibliographic references

General U.S. Geological Survey National Mineral Resource Assessment Team (2002)
Economic Robinson and Menzie (2012)
U.S. Geological Survey National Mineral Resource Assessment Team, 2002, Assessment of undiscovered deposits of gold, silver, copper, lead, and zinc in the United States—A portable document (pfd) recompilation of USGS Open-file Report 96-96 and Circular 1178, recompiled by Paul Schruben: U.S. Geological Survey Open-File Report 02-198, http://pubs.usgs.gov/of/2002/of02-198/.Robinson, G.R., Jr., and Menzie, W.D., 2012, Economic filters for evaluating porphyry copper deposit resource assessments using grade-tonnage deposit models, with examples from the U.S. Geological Survey global mineral resource assessment (ver 1.2, March 2014): U.S. Geological Survey Scientific Investigations Report 2010–5090–H, 21 p., http://pubs.usgs.gov/sir/2010/5090/h/.

Deposits and prospects associated with this tract

Name Type State Country Development Details
Baultoff deposit Alaska United States Prospect Details
Bond Creek deposit Alaska United States Occurrence Details
Carl Creek deposit Alaska United States Occurrence Details
Cathedral Creek prospect Alaska United States Prospect Details
Elizabeth prospect Alaska United States Prospect Details
Grubstake prospect Alaska United States Prospect Details
Horsfield deposit Alaska United States Prospect Details
London and Cape prospect Alaska United States Prospect Details
Neil prospect Alaska United States Prospect Details
Nike prospect Alaska United States Prospect Details
Orange Hill deposit 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
unnamed prospect Alaska United States Prospect Details
unnamed prospect Alaska United States Prospect Details
unnamed prospect Alaska United States Prospect Details
Pioneer prospect Alaska United States Prospect Details