2005 

Porphyry Copper Deposits of the

World: Database, Map, and Grade

and Tonnage Models 

By

Donald A. Singer

1

, Vladimir I. Berger

1

, and Barry C. Moring1 

Open-File Report 2005-1060 

Any use of trade, firm, or product names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

Available online at http://pubs.usgs.gov/of/2005/1060/ 

U.S. DEPARTMENT OF THE INTERIOR 

Gale A. Norton, Secretary 

U.S. GEOLOGICAL SURVEY 

Charles G. Groat, Director 

1 U.S. Geological Survey, Menlo Park, Calif. USA 
INTRODUCTION 

Mineral deposit models are important in exploration planning and quantitative 

resource assessments for two reasons: (1) grades and tonnages among deposit types are 

significantly different, and (2) many types occur in different geologic settings that can be 

identified from geologic maps. Mineral deposit models are the keystone in combining the 

diverse geoscience information on geology, mineral occurrences, geophysics, and 

geochemistry used in resource assessments and mineral exploration. Too few thoroughly 

explored mineral deposits are available in most local areas for reliable identification of the 

important geoscience variables or for robust estimation of undiscovered deposits—thus we 

need mineral-deposit models. Globally based deposit models allow recognition of 

important features because the global models demonstrate how common different features 

are. Well-designed and -constructed deposit models allow geologists to know from 

observed geologic environments the possible mineral deposit types that might exist, and 

allow economists to determine the possible economic viability of these resources in the 

region. Thus, mineral deposit models play the central role in transforming geoscience 

information to a form useful to policy makers. The foundation of mineral deposit models is 

information about known deposits—the purpose of this publication is to make this kind of 

information available in digital form for porphyry copper deposits. 

This report is an update of an earlier publication about porphyry copper deposits 

(Singer, Berger, and Moring, 2001). In this report we have added 84 new porphyry copper 

deposits and removed 12 deposits. In addition, some errors have been corrected and a 

number of deposits have had some information, such as grades, tonnages, locations, or 

ages revised. 

This publication contains a computer file of information on porphyry copper 

deposits from around the world. It also presents new grade and tonnage models for 

porphyry copper deposits and for three subtypes of porphyry copper deposits and a map 

showing the location of all deposits. The value of this information and any derived 

analyses depends critically on the consistent manner of data gathering. For this reason, we 

first discuss the rules used in this compilation. Next, the fields of the data file are 

considered. Finally, we provide new grade and tonnage models. 

RULES USED 

A mineral deposit is a mineral occurrence of sufficient size and grade that might, 

under the most favorable circumstances, be considered to have economic potential (Cox, 

and others, 1986). Deposits sharing a relatively wide variety and large number of attributes 

are characterized as a "type," and a model representing that type can be developed. 

Porphyry copper deposits consist of stockwork, disseminated, and breccia-hosted copper 

mineralization that is generally restricted to plutons and their immediate wall rocks. They 

may have parts containing skarn. Deposits that may be derived from, or affected by, 

hypogene and supergene processes are included in the models. Deposits that are primarily 

breccia pipes or skarns were excluded from this database. An important consideration at 

the data gathering stage is the question of what the sampling unit should be. Grade and 

tonnage data are available to varying degrees for districts, deposits, mines, and shafts. For 

the deposits in this file, the following rule was used to determine which ore bodies were 

combined. All mineralized rock or alteration within two (2) kilometers was combined into 

one deposit. Thus if the alteration zones of two deposits are within two kilometers of each 
other, they were combined. Such an operational spatial rule is necessary for defining 

deposits because we must be able to classify deposits in regions with highly variable 

geologic information and to avoid bias in estimating undiscovered deposits in resource 

assessments in areas where detailed information is lacking such as under cover. The twokilometer rule was developed to try to insure that deposits in grade and tonnage and spatial 

density models correspond to deposits as geologic entities. Rules such as the twokilometer rule used here are essential in order to have an internally consistent assessment 

system where the estimate of number of undiscovered deposits is consistent with the grade 

and tonnage model. For example, El Pachon in Argentina and Los Pelambres in Chile are 

here reported as one record (deposit) because of the two-kilometer rule, but with El Pachon 

in Argentina acting as a placeholder pointing to Los Pelambres in Chile which contains the 

information on both. 

DATA FIELDS 

The information on the porphyry copper deposits is contained in the files PorCu.FP6 and 

PorCu.txt which are FileMaker Pro 6 and tab-delineated text files respectively. The fields 

in both files are described below. 

Deposit Name 

The most recent deposit name, "NameDeposit", is used. There is another field, 

"OtherNames," which contains alternative names that have been used for the deposit. A 

third field, "Includes," provides the names of deposits that have been combined with the 

primary deposit as a result of the two-kilometer minimum separation rule. 

Locations 

A number of fields are provided to show the deposit's location. "Country" and 

"StateProvince" are used for general locations. "CountryCode" is an abbreviated version of 

the country information (Table 1). Degrees, minutes, and, in some cases seconds, of 

longitude and latitude are provided in the separate fields. Decimal degrees of latitude 

("LatitudeDecimal") and longitude ("LongitudeDecimal") are calculated from the degrees, 

minutes and seconds fields. Southern latitudes and eastern longitudes are negative values. 

The field "Map Number" is used to identify the location of the deposit on maps supplied in 

this publication. 

Activity 

Where the discovery date is know it is recorded ("DiscoveryDate"). If a deposit is known 

to be a prospect at the time of this publication it is recorded as a "yes" in the "Prospect?" 

field. If mining is known to have started, the date is listed in the "StartupDate" field. 

Grades and tonnages 

Data gathered for each deposit include average grade of each metal or mineral commodity 

of possible economic interest and the associated tonnage based on the total production, 

reserves, and resources at the lowest possible cutoff grade. All further references to 

tonnage follow this definition. All tonnages reported here ("Tonnage") are in millions of 
metric tons. Copper ("Copper grade") and molybdenum ("Molybdenum grade") grades are 

reported as percent of the metals. Gold ("Gold grade") and silver ("Silver grade") grades 

are reported as grams/metric ton of the metal. Grades not available (always for by-products) 

are treated as zero. Deposits that are known to be only partially drilled are considered as 

prospects and do not have their grades and tonnages reported in the grade and tonnage 

fields in order to avoid introduction of biases. The "Comments" field contains 

supplementary information about incompletely explored deposits and some grades such as 

Pt and Pd when available. Two significant digits are presented for gold, silver, and 

molybdenum grades, but three significant digits are used for tonnage and copper grades. 

Age 

In the field "DepositAge", ages are in standard divisions of geologic time or in millions of 

years when available. Ages are reported in millions of years before the present ("AgeMY" 

field) based on reported absolute (typically thermal dates) ages or midpoints of geologic 

time scale units (Remane, 1998). 

Mineralogy 

Information on the mineralogy of the deposits varies widely in quantity and quality. 

Depending on the purpose of a study and the researcher's interest, a report on a mineral 

deposit might contain a detailed list of alteration minerals and a mention of unnamed sulfide 

and sulfosalt minerals, a detailed list of ore minerals and mention of alteration in broad 

terms, a complete list of all minerals, or a sparse list of minerals. In some studies, the 

author attempted to list the relative or absolute amounts of each mineral. Unfortunately, 

these attempts are not common and frequently not comparable with many other reports 

because of different standards. Thus, it was decided to use only the presence or absence of 

minerals ("Minerals") in this file. Most rock forming minerals such as feldspar and quartz 

are not included. 

Types of porphyry copper deposits 

Each deposit type is coded ("Type") as appropriate deposit type number as listed in USGS 

Bulletins 1693 (Cox and Singer, 1986). Subtypes of porphyry copper deposits are defined 

in Cox and Singer (1992) as: porphyry Cu-Au (type 20c) if Au/Mo greater than or equal to 

30, porphyry Cu-Mo (type 21a) if Au/Mo less than or equal to 3, and porphyry Cu (type 

17) otherwise, where gold is in parts per million and molybdenum is in percent. Skarnrelated porphyry copper deposits (type 18a) were not addressed as a separate category 

because of the difficulty of making an operational definition. 

Size and shape of alteration, sulfide, and ore bodies 

To consistently capture information about the size and shape of alteration, sulfide (pyrite) 

and ore bodies as represented in two-dimensional projection to the surface, we use the 

rigorous procedures used for mineral grain images (Griffiths, 1967). The shortest 

dimension (b axis) is measured as the distance between parallel rules that just touch the 

object. After the short dimension is determined, the long axis is measured perpendicular to 

the b axis using the same criteria. Many of the alteration, ore, and sulfide zones can be well 

represented by an ellipse. Where published estimates of the projected area of the body are 
not available we estimated the area using the standard formula for area of an ellipse (area = 

3.14159 a b / 4). In some cases however, the body has significant concave parts and use of 

an ellipse to estimate area of the body would result in an over estimate of the area. An 

example of these effects is seen in the Malanjkhand ore-body in India that has a markedly 

concave shape and a measured area that is about half of that calculated assuming an ellipse 

shape-we used the measured area. The field "SulfideArea" represents the area of sulfides 

in square kilometers; the sulfide minor axis in kilometers is in the field "SulfideBAxis", and 

the major axis is in the field "SulfideAAxis". Area of alteration, alteration major axis, and 

minor axis are represented by the fields "AlterArea", "AlterAAxis", "AlterBAxis" 

respectively. The area of ore in square kilometers is in the field "OreArea", the major axis 

of ore is in "OreAAxis", and the minor axis in "OreBAxis". 

Spatially associated rocks 

Rocks in and around the porphyry copper deposit are recorded here in the same terms used 

in the published maps and reports. Reports of rocks from different sources were treated 

equally. We have used three fields in an attempt to provide some spatial information. The 

field "RocksInDeposit" is used for rocks that are only represented in the deposit itself and 

not observable on a regional map. Rocks that are recorded both in the deposit and on a 

regional map are placed in the field "RocksOnMapInDeposit". Rocks on a regional map, 

but not in the deposit are in the field "RocksOnMap". 

Emplacement Depth 

The depth of emplacement of the porphyry copper deposits in kilometers is recorded 

("EmplacementDepthkm") when it was estimated in the literature. 

Spatially related deposits 

Here we record other deposits by type that are within 5 ("Assoc Deposits less 5km") and 

within 10 ("Assoc Deposits less 10km") km of a porphyry copper deposit. In many 

situations, these other deposits are merely occurrences and not economic mineral deposits. 

Nevertheless, many of these occurrences can be typed and their types might provide 

important information about possible porphyry copper deposits. Each deposit type is coded 

as the deposit type number and deposit type as listed in USGS Bulletins 1693 (Cox and 

Singer, 1986) and 2004 (Bliss, 1992). In most cases the age of spatially associated 

deposits is not know. No attempt is made here to record the age in the rare case where it is 

known. 

Sources 

An attempt was made to refer to the papers/web sites that were used for each deposit 

("References"). In a few cases unpublished sources were used. 

GRADE AND TONNAGE MODELS 

Grade and tonnage models of mineral deposits are useful in quantitative resource 

assessments and exploration planning. Having some idea of the possible values of 

alternative kinds of deposits that might be sought is critical to good exploration planning. 
In quantitative resource assessments these models play two roles: first, grade and tonnage 

models can help classify the known deposits in a region into types and therefore aid in 

delineation of areas permissive for types; second, the models provide information about the 

potential value of undiscovered deposits in the assessment area and are key to economic 

analyses of these resources. Construction of grade and tonnage models involves multiple 

steps; the first is the identification of a group of well-explored deposits that are believed to 

belong to the mineral deposit type being modeled. Well-explored here means completely 

drilled in three dimensions. After deposits are identified, data from each are compiled. 

These data consist of average grades of each metal or mineral commodity of possible 

economic interest and tonnages based on the total production, reserves, and resources at the 

lowest available cutoff grade. Here we use the deposits that have tonnages recorded in the 

"Tonnage" field and exclude deposits with grades and tonnages only in the "Comments" 

field because we believe more exploration is needed for these deposits. 

For each deposit type these models help define a deposit, as opposed to a mineral 

occurrence or a weak manifestation of an ore-forming process. The grade and tonnage 

models are the frequency distributions of tonnage, copper grade, molybdenum grade, silver 

grade, and gold grade for each porphyry Cu type as represented in Table 1 by their 90th , 

50th, and 10th percentiles. Percentiles of grades that contain unreported values, such as 

Mo, Ag, and Au, were estimated using the lognormal distribution. On the basis of the 

Lillifors test, the distributions of the logarithm of tonnage and copper grade are not 

significantly different (at the one percent level) than those of lognormal distributions for all 

porphyry copper deposits and for each of the types classed here. 

If there were no differences in grades or tonnages among deposit types, we could 

use one model for all types. For this reason, it is desirable to perform some tests to 

determine if the types are significantly different with respect to grades or tonnages. 

Analysis of variance tests of differences in mean (logarithms) tonnage, copper, 

molybdenum, gold, and silver grades by type of porphyry copper deposit reveal significant 

differences in gold and molybdenum grade as expected because of how subtypes were 

defined. In addition, tonnages of the molybdenum-rich porphyry copper subtype are 

significantly larger than the porphyry copper and the porphyry copper-gold subtypes (Table 

1). 
Table 1—Grade and tonnage models of porphyry copper-gold, porphyry copper, porphyry 

copper-molybdenum, and all subtypes of porphyry copper deposits. 

Number 

deposits 

10th percentile 

of deposits 

50th percentile 

of deposits 

90th percentile 

of deposits 

Cu-Au (20c) Tons 112 1,100 220 32 

Cu grade 112 0.83 0.44 0.24 

Mo grade 112 0.006 0.002 0.0005 

Ag grade 112 4.5 1.4 0.5 

Au grade 112 0.79 0.4 0.15 

Cu (17) Tons 215 1,100 220 30 

Cu grade 215 0.79 0.44 0.26 

Mo grade 215 0.024 0.010 0.0045 

Ag grade 215 3.0 1.2 0.44 

Au grade 215 0.24 0.077 0.025 

Cu-Mo (21a) Tons 53 4,500 270 63 

Cu grade 53 0.73 0.45 0.19 

Mo grade 53 0.062 0.028 0.01 

Ag grade 53 4.6 1.5 0.5 

Au grade 53 0.047 0.012 0.003 

All Cu Tons 380 1,400 230 32 

Cu grade 380 0.80 0.44 0.25 

Mo grade 380 0.03 0.008 0.002 

Ag grade 380 3.8 1.3 0.40 

Au grade 380 0.57 0.095 0.016 

Number 

deposits 

10th percentile 

of deposits 

50th percentile 

of deposits 

90th percentile 

of deposits 

Cu-Au (20c) Tons 112 1,100 220 32 

Cu grade 112 0.83 0.44 0.24 

Mo grade 112 0.006 0.002 0.0005 

Ag grade 112 4.5 1.4 0.5 

Au grade 112 0.79 0.4 0.15 

Cu (17) Tons 215 1,100 220 30 

Cu grade 215 0.79 0.44 0.26 

Mo grade 215 0.024 0.010 0.0045 

Ag grade 215 3.0 1.2 0.44 

Au grade 215 0.24 0.077 0.025 

Cu-Mo (21a) Tons 53 4,500 270 63 

Cu grade 53 0.73 0.45 0.19 

Mo grade 53 0.062 0.028 0.01 

Ag grade 53 4.6 1.5 0.5 

Au grade 53 0.047 0.012 0.003 

All Cu Tons 380 1,400 230 32 

Cu grade 380 0.80 0.44 0.25 

Mo grade 380 0.03 0.008 0.002 

Ag grade 380 3.8 1.3 0.40 

Au grade 380 0.57 0.095 0.016 
Relationships among variables are important for simulations of grades, tonnages 

and estimated number of undiscovered deposits, for their affect on our understanding of 

how deposits form, and for their affect on our assumptions about resource availability. 

Average copper grade versus tonnage of all 380 porphyry copper deposits has a slight 

positive correlation that is not significant at the one percent level. Within the Cu group, 

tonnage has a low but significant correlation with copper grade (r = 0.18). The 

independence of grade and tonnage is expected when the relationship between copper 

content and tonnage of ore is examined—the two are highly correlated and grade is a ratio 

of the two. Ratios of highly correlated variables tend to be independent of each either. 

Tonnage is correlated with gold grade (r = -0.33, n = 229) and gold is correlated with 

molybdenum (r = -0.24, n = 135) and with silver (r = 0.36, n = 133). 

For the porphyry Cu-Au group, silver grades are correlated with tonnage (r = -0.40, 

n=48). In the porphyry Cu-Mo group, molybdenum grade is related to tonnage (r = -0.45, 

n = 53) and silver grades are correlated with molybdenum grades (r = 0.55, n = 31). Gold 

grades are correlated with molybdenum grade (r = 0.60, n = 62) in the porphyry Cu group. 

LOCATION MAP 

A map showing the locations of the deposits is provided in Map 1. The numbers on the 

map match the numbers in the "Map Number" field of the data file. 

REFERENCES 

Bliss, J.D., ed., 1992, Developments in deposit modeling: U.S. Geological Survey Bulletin 

2004, 168 p. 

Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: U.S. Geological Survey 

Bulletin 1693, 379 p. 

Cox, D.P., and Singer, D.A., 1992, Distribution of gold in porphyry copper deposits, in 

DeYoung, J.H., and Hammerstrom, J.M. eds., Contributions to commodity 

research: U.S. Geological Survey Bulletin 1877, p. C1-C14. 

Cox, D.P., Barton, P.R., and Singer, D.A., 1986, Introduction, in Cox, D.P. and Singer, 

D.A., eds., Mineral deposit models: U.S. Geological Survey Bulletin 1693, p. 1­

10. 

Griffiths, J.C., 1967, Scientific method in analysis of sediments; McGraw-Hill, New York, 

508 p. 

Remane, Jurgen, 1998, Explanatory note to global stratigraphic chart, in Circular of 

International Subcommission on Stratigraphic Classification (ISSC) of IUGS 

Commission on Stratigraphy, Appendix B: International Union of Geological 

Sciences (IUGS) Commission on Stratigraphy, v. 93, 11 p. 

Singer, D.A., Berger, V.I., and Moring, B.C., 2002, Porphyry copper deposits of the 

world: database, maps, and preliminary analysis; U.S. Geological Survey Open-file 

Report 02-268, http://geopubs.wr.usgs.gov/open-file/of02-268/ 

DISCLAIMERS 

This publication was prepared by an agency of the United States Government. Neither the 

United States Government nor any agency thereof, nor any of their employees, makes any 
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Reference therein to any specific commercial product, process, or service by trade name, 

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warranty, expressed or implied, is made by the USGS as to the accuracy of the data and 

related materials and (or) the functioning of the software. The act of distribution shall not 

constitute any such warranty, and no responsibility is assumed by the USGS in the use of 

this data, software, or related materials. 

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FILES 

of2005-1060.pdf (PDF file describing all contents.) 

COUNTRY_CODES.XLS (A text file relating country codes to country names.) 

PorCu.FP6 (A FileMaker Pro6 file containing the porphyry copper database.) 

PorCu.txt (A tab-delineated text file containing the porphyry copper database.) 

PorCu.xls (An Excel file containing the porphyry copper database.) 

Map_1.pdf. Locations of all porphyry copper deposits in the PorCu.FM5 file plotted on a 

world map. 

PorCu_meta.txt (metatdata in FGDC format)