Western Mexican Basin and Range and Laramide Southwest

Late Cretaceous to middle Eocene island arc and continental arc rocks along the western margin of Mexico and extending north into the U.S.
Tract ID 003pCu3006x
Country Mexico-United States of America
Commodity Cu
Study area name Mexico and US revised
Tectonic setting continental margin
Deposit type porphyry copper
Grade-tonnage model General porphyry copper model (Singer and others, 2008)
Geologic age
Geologic feature age Late Cretacous through Eocene (Laramide)
Generalized age Tertiary-Paleogene
Oldest rocks age 99.6Ma
Youngest rocks age 33.9Ma
Age range 65.7Ma
Identified Cu resources 5,400,000metric tons
Mean Cu (t/sq km) 242t/sq km
Map scales used 250K, 500K

Results of the assessment

Assessment date 2012
Estimators Francisco Cendejas-Cruz, Enrique Espinosa, Floyd Gray, Jane Hammarstrom, Steve Ludington, Gilpin Robinson, Efren Pérez-Segura, Martín Valencia-Morena, José Luis Rodríguez-Castañeda, Lukas Zürcher AND 1996 USGS National Mineral Resource Assessment T
Assessment depth 1km
Quantitative assessment Yes

Estimated number of deposits

Number of deposits Confidence level
2 90%
5 50%
9 10%
9 5%
9 1%
Mean estimated deposits 5.17 ±2.59 (0.5%)
Probability of mean 0.29
Probability of no copper 0.04

Estimated deposit density

(sq km)
Deposit density
per 100,000 sq km
2 7.17 82,639 9

Mean estimated tonnage

Copper 20,000,000
Molybdenum 560,000
Gold 510
Silver 7,000
Ore 4,100

Undiscovered copper resource

Confidence level 95% 90% 50% 10% 5%
Tonnage 370,000 1,600,000 12,000,000 48,000,000 75,000,000

Economic analysis

Fraser country Mexico
Fraser type 0.68%
Fraser high 0.32%
Typical cost 1%
High cost 0%
Infrastructure setting Typical
Comments on depth 76% cover; skew deep
Expected depth distribution
0 - 250m 0.1
250m - 500m 0.3
500m - 1km 0.6
Economically recoverable resources
Copper 13,000,000t
Molybdenum 260,000t
Gold 260t
Silver 4,200t
Probability no econ recoverable 0.24
Econ NPV 3,300x $1M
Exp dollars 35x $1M/100,000 sq km
Exp value class Medium

Bibliographic references

General Hammarstrom and others (2010) and 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
Batacosa prospect Sonora Mexico Occurrence Details
La Fortuna prospect Sonora Mexico Occurrence Details
La Sierrita/La Cobriza prospect Sonora Mexico Occurrence Details
Los Humos prospect Sonora Mexico Occurrence Details
Picacho prospect Sonora Mexico Occurrence Details
Piedras Verdes deposit Sonora Mexico Past Producer Details
Ajo deposit Arizona United States Occurrence Details
Stray Elephant prospect Arizona United States Prospect Details