1. Mineral Resources
  2. Online Spatial Data
  3. Global assessment of undiscovred copper resources

Skolai Arc - Eastern Alaska

XML
JSON
KML
Late Paleozoic Skolai Arc of the Wrangellia terrane; south of the Denali Fault
Tract ID 003pCu5001
Country United States of America
Commodity Cu
Study area name United States revised - Alaska
Tectonic setting island arc
Deposit type porphyry copper
Grade-tonnage model General porphyry copper model (Singer and others, 2008)
Geologic age
Geologic feature age Late Paleozoic
Generalized age Paleozoic
Oldest rocks age 359Ma
Youngest rocks age 251Ma
Age range 108Ma
Known prospects 2
Mean Cu (t/sq km) 99t/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
1 10%
2 5%
3 1%
Mean estimated deposits 0.41 ±0.82 (2.02%)
Probability of mean 0.15
Probability of no copper 0.71

Estimated deposit density

Known
deposits		 Total
deposits		 Area
(sq km)		 Deposit density
per 100,000 sq km
0.41 17,150 2

Mean estimated tonnage

Copper 1,700,000
Molybdenum 43,000
Gold 40
Silver 630
Ore 340

Undiscovered copper resource

Confidence level 10% 5%
Tonnage 3,100,000 7,100,000

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; lots of cover
Expected depth distribution
0 - 250m 0.1
250m - 500m 0.3
500m - 1km 0.6
Economically recoverable resources
Copper 760,000t
Molybdenum 16,000t
Gold 12t
Silver 280t
Probability no econ recoverable 0.99
Econ NPV 120x $1M
Exp dollars -3.11x $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
The Dome prospect Alaska United States Prospect Details