Nonfuel Mineral Resources in the 

United States-Mexico Border RegionA Progress Report on Information Available from the 

=:en~L tor Inter-American Mineral Resource Investigations (CIMRI) 

U.S. GEOLOGICAL SURVEY CIRCULAR 1098 
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Nonfuel Mineral Resources in the 

United States-Mexico Border RegionA Progress Report on Information Available from the 

Center for Inter-American Mineral Resource Investigations (CIMRI) 

By Greta J. Orris, Norman J Page, John-Mark G. Staude, Karen S. Bolm, 

Marguerite Carbonaro, Floyd Gray, and Keith R. Long 

U.S. GEOLOGICAL SURVEY CIRCULAR 1098 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1993 
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary 

U.S. GEOLOGICAL SURVEY 

ROBERT M. HIRSCH, Acting Director 

For sale by U.S. Geological Survey, Map Distribution 

Box 25286, MS 306, Federal Center 

Denver, CO 80225 

Any use of trade, product, or firm names in this publication is for descriptive purposes only and 

does not imply endorsement by the U.S. Government. 

Published in the Eastern Region, Reston, Va. 

Manuscript approved for publication October 21 , 1993. 

Library of Congress Cataloging in Publication Data 

Nonfuel mineral resources in the United States-Mexico border region: a progress report 

on information available from the Center for Inter-American Mineral Resource 

Investigations (CIMRI) I by Greta J. Orris ... [et al.]. 

p. em. - (U.S. Geological Survey circular ; 1098) 

Includes bibliographical references (p. ). 

Supt. of Docs. no.: I 19.4/2:1098 

1. Mines and mineral resources-Mexican-American Border Region. I. Orris. G.J. 

II. Series. 

TN23.9.N66 1993 

553' .0973-dc20 93-46585 

CIP 
CONTENTS 

Abstract........................................................................................... 1 

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Mining History of the Border Region. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

Land Status and Infrastructure... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

Geologic Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Data Sources and Collection.................................................................. 10 

Mineral-Resource Distribution................................................................ 13 

Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 

References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 

FIGURES 

1. Location map showing the area defined as the U.S.-Mexico border region for this report........................ 2 

2-4. Sketch maps of the U.S.-Mexico border region and adjacent areas showing the distribution of2. Lands known to be closed to mineral exploration and (or) development........................................ 6 

3. Major standard-gauge railroad routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

4. Selected primary paved highways and roads......................................................................... 8 

5. Maps showing simplified geology and geologic provinces in and adjacent to the U.S.-Mexico border 

region.............................................................................................................................. 9 

6. Map showing generalized distribution of volcanic and plutonic rocks in and adjacent to the U.S.-Mexico 

border region..................................................................................................................... 10 

7. Map of the U.S.-Mexico border region showing the number of Mineral Resources Data System records 

for sites containing metallic and industrial mineral commodities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

8-14. Maps of the U.S.-Mexico border region and adjacent areas showing the distribution of mines, prospects, 

and occurrences of8. All metallic and industrial mineral commodities for which the Mineral Resources Data System 

included records as of May 1993 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

9. Gold and silver . . . ...... .. ...... ... . ... . .... .. .. .. .. .... ...... ...... ...... .. ...... .... ...... ..... .... .......... ..... ..... .. 14 

10. Lead and (or) zinc and copper.......................................................................................... 14 

11. Construction materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 

12. Gypsum, zeolites, and diatomite . .. . . . . . . . . . . . . . . . . .. . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . .. . .. . . . .. . . . . .. . . . .. . . .. . . 17 

13. Barite, fluorite, and celestite............................................................................................ 17 

14. Clays, evaporite (halite or potash), sodium carbonate or sodium sulfate, and sulfur......................... 18 

TABLES 

1. Historical events related to mining in the U.S.-Mexico border region.... .. .. . . .. . .. . . . . .. . .. .. . .. .. . .. . . . . .. . . . .. .. .. .. . 4 

2. Some general sources of information on mineral resources of the U.S.-Mexico border region...................... 12 

3. Mineral commodities produced within the U.S.-Mexico border region................................................... 13 

4. Significant industrial mineral commodities used in agriculture, infrastructure, and environmental improvements 

in the U.S.-Mexico border region............................................................................................... 15 

m 
IV GEOLOGIC TIME CHART 

GEOLOGIC TIME CHART 

Terms and boundary ages used by the U.S. Geological Survey in this report 

EON ERA PERIOD EPOCH 

Holocene 

Quaternary Pleistocene 

Neogene Pliocene 

Cenozoic Subperiod Miocene 

Tertiary Paleogene Oligocene 

Subperiod Eocene 

Paleocene 

Cretaceous Late 

Early 

Late 

Mesozoic jurassic Middle 

Early 

Late 

Triassic Middle 

Early 

Permian Late 

Phanerozoic Early 

Late 

Pennsylvanian Middle 

Carboniferous Early Periods 

Mississippian Late 

Early 

Late 

Devonian Middle 

Paleozoic Early 

Late 

Silurian Middle 

Early 

Late 

Ordovician Middle 

Early 

Late 

Cambrian Middle 

Early 

Late Proterozoic 

Proterozoic Middle Proterozoic 

Early Proterozoic 

late Archean 

Archean Middle Archean 

Early Archean 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - (3800l)- - - - - - - - - - - - - - - - - - -

pre-Archean1 

'Rocks older than 570 Ma also called Precambrian, a time term without specific rank. 2

1nformal time term without specific rank. 

AGE ESTIMATES OF 

BOUNDARIES IN 

MILLION YEARS (Ma) 

0.010 

1.6 

5 

24 

38 

55 

66 

~ 96 

138 

205 

-240 

290 

-330 

360 

410 

435 

500 

1

-570 

900 

1600 

2500 

3000 

3400 
Nonfuel Mineral Resources in the 

United States-Mexico Border RegionA Progress Report on Information Available from the 

Center for Inter-American Mineral Resource Investigations (CIMRI) 

By Greta J. Orris, Norman J Page, John-Mark G. Staude, Karen S. Bolm, Marguerite Carbonaro, 

Floyd Gray, and Keith R. Long 

ABSTRACT 

The exploitation of minerals has played a significant 

role in population growth and development of the U.S.-

Mexico border region. Recent proposed changes in regulations related to mining in the United States and changes in 

mining and investment regulations in Mexico have led to 

increased mineral exploration and development in Mexico, 

especially in the border region. As a preliminary step in the 

study of the mineral industry of this area, the Center for 

Inter-American Mineral Resource Investigations (CIMRI) 

of the U.S. Geological Survey has compiled mine and 

occurrence data for nonfuel minerals in the border region. 

Analysis of this information indicates that a wide variety of 

metallic and industrial mineral commodities are present 

which can be used in agriculture, infrastructure, environmental improvement, and other industries. Therefore, mining will continue to play a significant role in the economy of 

this region. 

INTRODUCTION 

Increasing mineral trade and the prospect of a free 

trade agreement with Mexico (North American Free Trade 

Agreement) raise many mineral-resource issues specific to 

the U.S.-Mexico border area. A free trade agreement, along 

with current and anticipated favorable changes in the 

Mexican mining and investment codes and increasing regulation in the United States, could lead to a revival of the 

transborder mining industry that existed in the late 19th 

century (Martino and others, 1992). Urban, agricultural, 

and industrial growth along the border will likely accelerate 

under a free trade agreement, resulting in increased demand 

for development and improvement of the infrastructure and 

for goods which require minerals that can be supplied from 

either side of the border. Pressure is already mounting to 

clean up industrial contamination along the border, an effort 

that would create a strong local demand for minerals useful 

for the treatment of effluent and the storage of hazardous 

wastes. 

Many borderlands geologists know that the mineral 

resources of the border area are able to support a substantial 

minerals industry that could meet the demands of an 

expanding economy and population. This report is for 

policymakers, corporate managers, borderlands specialists, 

and the general public, who may have scant knowledge of 

borderlands mineral resources and of the mineral-related 

policy issues. Information regarding resource limitations, 

such as water supply, prior land-use decisions, or lack of 

infrastructure, that may affect economic development of the 

border area is widely dispersed or unavailable. The Center 

for Inter-American Mineral Resource Investigations 

(CIMRI), which is part of the U.S. Geological Survey, is 

involved in a multiyear study to investigate the geologic, 

economic, and environmental aspects of the minerals industry in the U.S.-Mexico border region. 

This report begins with a brief overview of the history 

of the border region as it relates to mineral-resource 

development. Sections on land status, infrastructure, geologic setting, and data sources lead to the summary of 

currently available mineral-resource data for the border 

region. Maps of mineral-commodity occurrences are 

included. The primary archive of data on mineral occurrences, prospects, and deposits utilized for this project is the 

Mineral Resources Data System (MRDS) of the U.S. 

Geological Survey, which is described below in "Data 

Sources and Collection." 

For this report, the border region is defined to include 

parts of southern California, Arizona, New Mexico, and 

Texas on the U.S. side and the northern parts of Baja, 

Sonora, Chihuahua, Coahuila, Nuevo Leon, and Tamauli-
2 NONFUEL MINERAL RESOURCES IN THE UNITED STATES-MEXICO BORDER REGION 

122°30' 93° 36°30',......,.--------.::----r--------r---------r-----,-----------. 

Pacific Ocean 

0 200 MILES 

I I 

0 250 KILOMETERS 

ARIZONA NEW MEXICO 

~. 

TEXAS 

TAMAULIPA 

of 

Mexico 

21°~---------------------------------------~-------------------~--------~ 

Figure 1. Area defined as the U.S.-Mexico border region for this report. Area shaded. 

pas on the Mexican side of the border (fig. 1). The 

boundaries of the CIMRI study area were selected to 

include the major population centers away from the actual 

border and do not confonn to existing political boundaries. 

Major population centers play important roles in the transport, processing, marketing, and demand for mineral commodities. 

MINING HISTORY OF THE BORDER 

REGION 

From pre-Columbian through modem time, the border 

region has played a vital role in the settlement and development of western North America. The resources of the 

border region were first utilized by North American indigenous peoples, who mined a wide variety of materials 

(Forrester, 1969; Gerald, 1984). Turquoise, jet (gem material made of dense coal), opal, copper, and silver were 

mined for decorative uses. Coal was utilized as a fuel. 

Obsidian and other igneous rocks were mined to produce 

projectile points, mortars and pestles, grinding stones, stone 

axes, and a variety of other tools. Clay, asbestos, and other 

materials were used to make pottery. Salt was mined for use 

as a preservative and flavoring, and sodium sulfate for use 

as a purgative. Extraction of these mineral products established some of the early flows of resource materials from 

the border region to other parts of North America. 

The Spanish Crown granted the right to mine in the 

New World in 1504; from the 16th century to the early 19th 

century, the Spanish explored for and then exploited the 

silver and gold resources of the border region (table 1). 

Mining was done under a variety of laws and regulations 

that affected claim sizes, mining rights, royalties, taxes, 

ownership, and the level of exploration and development. 

Exploration and mining in the study area were also affected 

by repeated conflicts between settlers and miners and native 

peoples until the late 19th century. Near the present U.S.-

Mexico border, mines were operated only sporadically due 

to the threat of violence. 

Early discoveries during the Spanish Colonial period 

include silver districts in Chihuahua such as Parra! ( discovered about 1544), Batopilas (1632), and Santa Eulalia 

(1652) (Alvarez-Ruiz, 1983). These districts have produced 

for centuries and are responsible for the border region 

becoming one of the world's largest silver-producing areas. 

Many other mineral discoveries were made during the early 

Spanish Colonial period, including gold in the San Juan 

Bautista district, Sonora, in 1657 and silver along the 

Sonora-Arizona border in 1736 (Officer, 1991). In the 

north, salt was being produced in the Estancia Valley of 

New Mexico by the year 1650 to supply the silver-mining 

operations at Parra! in Chihuahua (Bachman, 1965). 

The 19th century saw continuous expansion of mining 

in the border region and the identification of other metal 
LAND STATUS AND INFRASTRUCTURE 3 

resources still produced today. In 1803, the United States 

acquired rights to much of the land west of the Mississippi 

through the Louisiana Purchase, and its citizens began to 

rapidly spread westward. In 1810, Mexico revolted against 

Spanish Colonial rule. By the end of the revolution in 1821, 

much of the mining industry in the new country of Mexico 

was in shambles, and foreign investment was restricted. 

Continuing conflicts during the next 40 years, including the secession of Texas in 1836, the U.S.-Mexican war 

( 1845-48), and the Mexican Revolution against France 

( 1862-67), hampered efforts to rebuild the Mexican mining 

industry. At the end of its war with Mexico, the United 

States acquired most of the territory that is now New 

Mexico, Arizona, and California through the Treaty of 

Guadeloupe Hidalgo and the Gadsden Purchase. The end of 

the U.S.-Mexico war also led to the establishment in 1851 

of a "Free Zone" (no tariffs on most imports) at Matamoros, 

Mexico. In the next 30 years, the "Free Zone" was 

expanded across Mexico, until it was a zone approximately 

20 kilometers ( 12 miles) wide spanning the entire U.S.-

Mexico border region (Engineering and Mining Journal, 

1905). When Porfirio Diaz became president and dictator of 

Mexico in 1877, American and Canadian firms were 

encouraged to operate freely in that country (Griggs, 1907). 

Hundreds of mines opened up during this time, and the 

border-region industries grew as industrialization spread 

over the continent (Heylmun, 1988). Housing, roads, aqueducts, and railroad lines all required natural resources, 

many of which were produced in the border region. As the 

population of northern Mexico and the southwestern United 

States grew, so did the demand for raw materials and 

transportation of those materials. This situation lasted until 

the turn of the century, when social inequities and unrest led 

to widespread strikes, the end of the "Free Zone," restrictions on foreign investments, and, eventually, the third 

Mexican Revolution ( 191 0-17). 

Following the revolution, Mexico entered a period of 

nationalism where foreign control of mining and other 

industries was restricted and the flow of minerals across and 

within the border region was diminished. In 1926, Mexico 

prohibited any new foreign ownership of mines. This was 

followed by nationalization of certain mineral commodities 

and reservation of large tracts of land. In 1937, Mexico 

nationalized the railroads and, 1 year later, the oil industry. 

Significant mineral discoveries continued to be made 

during the first half of the 20th century. Potash was 

discovered at Carlsbad, New Mexico (1925), and celestite 

in Coahuila (prior to 1942). Iron was discovered at La 

Perla, Chihuahua (1937). Minor amounts of iron, tungsten, 

nickel, and cobalt were extracted from the border region 

and sent to Allied Forces during World War II. After World 

War II, mining in the border region boomed as large 

low-grade copper, molybdenum, and gold resources, as 

well as other deposits, were more fully exploited. 

In the second half of the 20th century, there has been 

a diversification of uses and exploitation methods for 

natural resources within the border region. As late as the 

1950's, commodities such as celestite and fluorite (at Pico 

Etero, Coahuila, in 1952) became significant products of 

the region. Today natural resources flow across the border, 

and large amounts flow in and out of the border region. The 

Mexican government is reversing many of the nationalistic 

policies of the earlier part of the century. Revision of the 

mining regulations in 1990 allows foreign control of mining 

projects for 12 years, and investment policies have been 

liberalized in the last few years. These changes have large 

numbers of international mining firms, including Canadian 

and American companies, investing in mineral exploration 

and development in Mexico, especially in the border 

region. Historically, the role of minerals and other resources in the region has been significant. In the coming 

century, as international commerce becomes greater, 

resources in the border region should continue to play an 

important role in socioeconomic development. 

LAND STATUS AND INFRASTRUCTURE 

In natural-resource development, one of the more 

important issues is land status. Availability of land for 

mineral exploration and development influences costs associated with exploitation. In the United States, the Bureau of 

Land Management in the U.S. Department of the Interior is 

responsible for the survey of Federal lands and maintains 

public land records and records of mining claims. In the 

United States, national park, Wilderness, and Department 

of Defense lands are mostly excluded from mineral exploration and production, whereas most lands managed by the 

Forest Service (part of the U.S. Department of Agriculture) 

and the Bureau of Land Management are open to mineral 

exploration and development under Federal regulation. 

Exploration for and development of some commodities on 

Federal lands can be done only under Federal lease; leasing 

of mineral rights is under the aegis of the Bureau of Land 

Management. Indian- and State-owned lands have diverse 

regulations governing mining, but exploration is severely 

restricted on most Indian lands. With the exception of 

Texas, which contains State-owned and privately owned 

land almost exclusively, the U.S. portion of the borderlands 

study area consists largely of Federal and Indian lands (fig. 

2). Taxes, royalties, and other fees are often partially 

determined by the land status and commodity. 

In Mexico, land status and the system controlling 

mineral exploration and development provide a significant 

contrast. In Mexico, just as in the United States, national 

parks and military training grounds are excluded from 

mineral exploration. However, the land-governing system 

set up through the Federal and State governments delegates 

control to individual municipios. Municipios, like counties 
4 NONFUEL MINERAL RESOURCES IN THE UNITED STATES-MEXICO BORDER REGION 

Table 1. Historical events related to mining in the U.S.-Mexico border region. 

[Data from Alvarez-Ruiz (1983), Bachman (1965), Diaz-Unzueta (1986), Forrester (1969), Lacy (1987), Martino and others (1992), Officer (1991), 

Ord6fiez Cortes (1986-90), Pearson (1974), and Ruiz and others (1986)] 

16th Century 17th Century 17th Century-Continued 18th Century 18th Century -Continued 

1504-Spanish Crown 1600-Smelter at 1666-Discovery of 1702-Discovery of 1749-Discovery of 

grants right to mine in Parral, Chihuahua, Cusihuiriachic silver and Terrazas copper deposit, Palmarejo lead deposit, 

New World begins to process silver gold deposit, Chihuahua Chihuahua Chihuahua 

ores 

1536 to 1550-Viceroy 1628-Discovery of 1670-First use of 1719-Discovery of 1750(?)-Discovery of 

Mendoza Codes (include Guazapares silver and pumps to dewater a lead, zinc, and silver Ajo copper district and 

mining laws) gold district, Chihuahua mine at Parral, replacement deposits at Arivaca (?) district, 

Chihuahua Aldama, Chihuahua Arizona 

1544(?)-Discovery of 1630-Discovery of 1674-Silver and lead 1725-Silver discovered 1760-Jesuit missionarsilver and lead at Parral, Urique polymetallic vein discovered at Naica, in "Planchas de Plata" ies discover and exploit 

Chihuahua district, Chihuahua Chihuahua district, Sonora gold and silver at Cananea, Sonora 

1548-Vein mining of 1632-Discovery of 1675-Minting of first 1728-Spanish forbid 1772-Discovery of 

copper begins at Cerro Batopilas silver district, gold money in Mexico; production of mercury Dolores gold and silver 

Panuco, Coahuila Chihuahua previously all coinage in New World to protect veins, Chihuahua-Sonora 

was silver their monopoly; mercury border area 

was used to refine gold 

1565-Discovery of 1649-Discovery of La 1729-Discovery of 1774-Petition sent to 

gold at Santa Barbara, Calera lead and silver Poreachi lead deposit, King Carlos II asking 

Chihuahua skarn and General Trias Coahuila, and Ocampo for lower taxes, Mexican 

silver and gold veins, silver and gold deposit, currency, national 

Chihuahua Chihuahua mining, and education 

system 

1575-Saltillo, 1650(?)-Salt mining, 1732-Discovery of zinc 1783-Regal Code of 

Coahuila, founded; Estancia Valley, New veins, Uruachic district, Charles III-Reales 

agriculture and mineral Mexico Chihuahua Ordenanzas de la 

exploration center Minerfa de NuevaEspana 

1584-Regal Code of 1652 -Discovery of 1734-Discovery of 1799-Discovery of La 

Philip II (includes Santa Eulalia silver gold and copper in Cienega gold placers, 

mining regulations) district, Chihuahua; Chinipas area, Sonora Sonora 

undocumented reports and Chihuahua 

indicate discovery in 

1591 

1596-First smelter 1657-Discovery of 1736-Discovery of 

founded in Monterrey, gold in San Juan Arizonac (Arissona) 

Nuevo Le6n Bautista district, Sonora silver deposit near 

Nogales along the 

present Arizona-Sonora 

border 

1658-Discovery of San 17 40-Discovery of 

Francisco del Oro silver graphite in Sonora and 

and fluorite district, gold and silver veins at 

Chihuahua La Colorada, Sonora 

1748-Discovery of 

gold at Maguarichic, 

Chihuahua 
LAND STATUS AND INFRASTRUCTURE 5 

Table 1. Historical events related to mining in the U.S.-Mexico border region-Continued. 

19th Century 19th Century -Continued 20th Century 20th Century-Continued 

180 1-Discovery of 1860 -Cananea copper 1905-U.S. and 193 7-Discovery of 

Janos copper district, pipes begin production, Mexico begin joint La Perla iron deposit, 

New Mexico-Chihuahua Sonora smelter production at Chihuahua 

border Torreon, Coahuila, and 

Chihuahua, Chihuahua 

1804-Discovery of 1862 to 1867-Mexican 1905 - Diaz abolishes 1937 -Nationalization of 

Santa Rita copper Revolution against "Free Zone," enacts Mexican railroads 

deposit, New Mexico France tariffs on mineral 

imports to Mexico 

1810 to 1821-Mexican 1864-Arizona Territory 1908-Strikes in Mexi- 1938-Nationalization of 

Revolution against Span- Mining Code can border region cripple Mexican oil industry 

ish rule mining industry 

1811-Namiquipa silver 1868-Copper discov- 1910 to 1917 -Mexican 1942 or 1943-First proveins discovered, Chi- ered at Barranca del Revolution; foreigners duction of celestite (a 

huahua Cobre, Chihuahua lose effective control of source of strontium) in 

mines Mexico 

1823-Discovery of El 1870-First gold 1911 to 1917 -First 1950-Discovery of 

Pilar de Moris gold production from Baja open pit porphyry silver and lead at La 

deposit, Chihuahua, and California Norte at Real copper mines developed Encantada, Coahuila 

law allowing foreigners de Castillo at Ray, Arizona, Santa 

to own mines in Mexico Rita, New Mexico, and 

Ajo, Arizona 

1836-Texas declares 1870-Discovery of 1912-Frasch mining of 1952-Discovery of 

independence from gypsum(?) at Salinar de sulfur begins at Bryan fluorite at Pico Etero, 

Mexico Jaco, Chihuahua Mound salt dome, Gulf Coahuila 

Coast, Texas 

1845 to 1848-U.S.- 1873-First edition of 1924-El Azufre sulfur 1961-Foreign interests 

Mexican war, U.S. the periodical El Minero mine begins production, in Mexican mines 

acquisition of most of Mexicano Baja California limited to 49 percent 

California-Arizona-New 

Mexico area 

1851-Mexico estab- 1877-Production of 1925-Discovery of 1964-Discovery of 

lishes "Free Zone" (few copper starts at Bisbee, Carlsbad potash deposit, Hercules iron deposit, 

or no tariffs zone) Arizona New Mexico Coahuila 

at Matamoros; later 

extended across entire 

U.S.-Mexico border area 

1853 -Gadsden 1890-Morenci copper 1926-Mexico prohibits 

Purchase mine begins production new foreign-owned 

in Arizona mines; Ley de Industrias 

Min eras 

1855?-First production 1893-Production of 1934-Mexico nationalof graphite in Sonora zinc at Lampazos, izes mining of specified 

Sonora commodities and 

reserves lands; Ley 

Min era 
6 NONFUEL MINERAL RESOURCES IN THE UNITED STATES-MEXICO BORDER REGION 

122°30' 93° 

36°30' ,..-"1-------~--~:--------,----~------:-----,-----------, 

Pacific 

Ocean 

EXPLANATION 

• National parks and Wildernesses 

liD Military reservations 

fa Indian lands 

0 

I 

0 

160 MILES 

I I 

200 KILOMETERS 

, 

Gulf of 

Mexico 

~. 21°~-----------------------------------~--------------------~---------~ 

Figure 2. Distribution of lands known to be closed to mineral exploration and (or) development in and adjacent to the U.S.-Mexico 

border region. Data from Paul G. Schruben (U.S. Geological Survey, unpub. data, 1993). 

in the United States, have a governmental seat where 

mining documents are filed with the Agencia de Mineria. 

Municipio land is open to mineral exploration on a caseby-case basis, and agreements between the municipio government and individual companies are used to allocate 

mining lands. Most of the ranch land in the Mexico portion 

of the border region is privately held; the desert lands are 

typically government controlled. Taxes are paid to the State 

and Federal governments for all mining claims. 

Figure 2 shows various types of land excluded from 

mineral exploration in the border region. More exact 

information on land status should be obtained from the U.S. 

Bureau of Land Management (address in table 2) or 

Mexican municipio offices. 

Infrastructure plays a significant role in the ability of 

the borderlands to process and export mineral products. 

Infrastructure for the purposes of this report includes power 

sources and transportation routes. Power sources and facilities in the Western United States are shown on a map 

prepared by the U.S. Department of Energy (1992). Much 

like the U.S. railroad system, that in Mexico was constructed largely in the late 19th century and earliest 20th 

century. Although as much as 80 percent of the capital for 

this infrastructure development came from the United States 

(Martino and others, 1992), the railroads were nationalized 

in 1937. Figure 3 shows major standard-gauge railroad 

routes within and near the study area. Cross-border connections exist at various locations (fig. 3). The density of 

railroad lines in the southwestern part of the study area is 

low, and there is no rail service in Baja California Norte. 

Scheduling problems, lack of railcars, and other bottlenecks 

have led to truck rather than rail transport of ore in many 

Mexican mining operations (Martino and others, 1992). 

Recent decentralization of Mexican railroad operations has 

improved the speed and efficiency of the rail transport 

system; however, service to the rural areas has been 

diminished. 

Over 65,000 kilometers (40,000 miles) of paved roads 

exist in Mexico (Martino and others, 1992), but most of 

them are in or near Mexico City; the density of paved roads 

in the border region is low (fig. 4). Nevertheless, trucking 

is the major transport mode in northern Mexico, operating 

largely on dirt roads. In Mexico, the mining industry relies 

heavily on truck transport. Paved roads link the United 

States and Mexico at 10 border cities, and the daily 

international truck commerce is valued in millions of 

dollars. 

GEOLOGIC SETTING 

The U.S.-Mexico border region extends 1,800 kilometers (1, 100 miles) and, for purposes of this discussion, can 

be divided into six geologic provinces (fig. 5) from east to 
GEOLOGIC SETIING 7 

122°30' 

36°30' ,...,-------~---r--------"T"""------..,----.,.-..---,---------..... 

Pacific 

Ocean 

0 160 MILES 

I I I 

0 200 KILOMETERS 

Gulf of 

Mexico 

\.e 21° M------------------------------------~~-------------------~--------~ 

Figure 3. Major standard-gauge railroad routes in and adjacent 

to the U.S.-Mexico border region. Modified from Mexico 

Secretarfa de Comunicaciones y Transportes (1990) and U.S. 

Geological Survey (1970). State names shown in figure l. 

Selected cities indicated by numbers: 1, Los Angeles; 2, San 

Diego-Tijuana; 3, Mexicali; 4, Phoenix; 5, Tucson; 6, Nogales; 

west: (1) the Gulf of Mexico Coastal Plain, (2) Paleozoic 

and Mesozoic platform rocks, (3) an area of terrestrial 

volcanism, (4) an area of structural extension, (5) a transitional area between platform rocks and the area of extension, and (6) an accreted terrane. These provinces and their 

associated mineral commodities are briefly described 

below. 

The Gulf of Mexico Coastal Plain is the easternmost 

geologic province and is composed of the Tertiary to 

Holocene sedimentary rocks of Texas, Tamaulipas, and 

Nuevo Leon shown on the simplified geologic map in figure 

5A and geologic province map in 5B. These rocks are 

relatively undeformed and overlie Paleozoic basement. 

Significant mineral deposits in the Gulf of Mexico Coastal 

Plain include sulfur, evaporites, and clays. 

To the west of the Gulf of Mexico Coastal Plain are 

platform rocks of Paleozoic and Mesozoic age in western 

Texas, New Mexico, southern Tamaulipas, Nuevo Leon, 

and Coahuila. These dominantly carbonate rocks overlie 

Precambrian basement. Paleozoic and Mesozoic sedimentary rocks are also in the Colorado Plateau area of northwestern New Mexico and northeastern Arizona. Silver is 

the most important metal mined in the area of Paleozoic and 

7, Hermosillo; 8, Douglas; 9, Albuquerque; 10, El PasoJuarez; 11, Chihuahua; 12, Hidalgo del Parral; 13, PresidioOjinaga; 14, Amarillo; 15, Del Rio-Villa Acuna and Eagle 

Pass-Piedras Negras; 16, Monclova; 17, Monterrey; 18, LaredoNuevo Laredo; 19, Dallas-Ft. Worth; 20, San Antonio; 21, 

Brownsville-Matamoros; and 22, Houston. 

Mesozoic rocks, although lead-zinc-silver replacement 

deposits and small copper deposits have also been mined. 

This province is also a major source of celestite (which 

yields strontium), fluorite, and potash. Other industrial 

minerals produced from Paleozoic and Mesozoic platform 

rocks include barite, sulfur, and sodium sulfate. 

In the central part of the study area, a third geologic 

province is formed by the largely terrestrial volcanic rocks 

of west-central New Mexico, east-central Arizona, western 

Chihuahua, and eastern Sonora. Major mineral products of 

this area include silver and some gold, copper, pumice, and 

perlite. 

The fourth province is a zone of extension. This 

province, the Basin and Range, is composed largely of 

Tertiary volcanic rocks and intervening basin fill and 

extends from southeastern California southeast through 

most of Sonora and east-southeast through Arizona and 

New Mexico to westernmost Texas and eastern Chihuahua. 

The Basin and Range province is possibly the richest in 

mineral wealth. World-class porphyry copper and gold 

deposits are found in this environment. Other mineral 

products include barite, borates, clays, diatomite, evaporites, fluorite, lead, zinc, and zeolites. 
8 NONFUEL MINERAL RESOURCES IN THE UNITED STATES-MEXICO BORDER REGION 

122°30' 

36°30' ,.....,.--~~---~----r---------r------or----.------r----------, 

Pacific 

Ocean 

0 160 MILES 

I I I 

0 200 KILOMETERS 

21°~--------------------------------._ __________________ ~--------~ 

Figure 4. Selected primary paved highways and roads in and 

adjacent to the U.S.-Mexico border region. Modified from 

Mexico Secretarfa de Comunicaciones y Transportes (1990) 

and Rand McNally (1989). State names shown in figure 1. 

Selected cities indicated by numbers: 1, Los Angeles; 2, San 

In Arizona, a southeast-trending transition zone occurs 

between the Basin and Range province to the southwest and 

platform rocks to the northeast. This area is the fifth 

geologic province and contains the most extensive exposures of Precambrian rocks in the border study region. 

These very old rocks are known for the massive sulfide 

deposits near Jerome and Bagdad. 

The sixth province is the far western part of the study 

area; it consists of accreted terranes and includes Mesozoic 

plutonic, sedimentary, and metamorphic rocks with Tertiary to Holocene basin fill. Gold is the dominant mineral 

product. 

Figure 6 shows the distribution of Tertiary and Quaternary volcanic rocks and Paleozoic through Tertiary 

intrusive rocks. Magmatically the compositions vary widely 

from alkalic in the east to calc-alkalic and alkalicmetaluminous in the west (Clark and others, 1982); thus, 

the mineral commodities associated with these rocks vary 

widely. The deposits in the border region formed during as 

many as five distinctive magmatic-tectonic pulses. In the 

Jurassic, shearing and mafic magmatism gave rise to minor 

metallic ore deposits. During the Cretaceous, gold-silver 

veins, copper and tungsten skarns, and numerous pegmaDiego; 3, Tijuana; 4, Mexicali; 5, Phoenix; 6, Tucson; 7, 

Nogales; 8, Hermosillo; 9, Albuquerque; 10, El Paso-Juarez; 

11, Chihuahua; 12, Hidalgo del Parral; 13, Presidio-Ojinaga; 

14, Amarillo; 15, Monclova; 16, Monterrey; 17, Dallas-Ft. 

Worth; 18, San Antonio; and 19, Houston. 

tites formed in the batholithic regions of the far western 

border region. 

The Late Cretaceous and early Tertiary was a time of 

extensive volcanic and plutonic activity (known as the 

Laramide orogeny). World-class copper-molybdenum porphyry, silver-gold, and lead-zinc-silver deposits formed in 

and around the area during this period. From 80 million to 

40 million years ago, the center of magmatism transgressed 

from west to east and caused multiple periods of magmatism and mineralization to affect the same area. These 

multiple events led to extensive mineralization of the border 

region. As the magmatism moved eastward, hydrothermal 

ore deposits formed progressively to the east. 

During the middle Tertiary 36 million to 20 million 

years ago, volcanoes and felsic magmatism generated 

numerous gold-silver, lead-zinc-silver, and fluorite deposits. The environments of mineralization ranged from continental volcanic and magmatic environments to fault-block 

basins; these areas extend from Arizona and New Mexico 

southward through most of western Mexico. Late Tertiary 

to Holocene igneous activity is associated with hot-spring 

gold, red-bed copper, volcanic sulfur, borate, and zeolite 

deposits. Magmatic rocks of late Tertiary age are concentrated near the Gulf of California. 
Pacific 

Ocean 

EXPLANATION 

Q Holocene and Pleistocene 

sedimentary rocks 

1:1 Tertiary sedimentary rocks .b 

[I) Mesozoic sedimentary rocks 

E3 Paleozoic sedimentary rocks 

• Paleozoic and Precambrian 

metamorphic rocks; 

Precambrian sedimentary rocks 

• Intrusive and volcanic rocks 

of all ages 

122"30' 

21' 

Pacific 

Ocean 

EXPLANATION 

1:1 Coastal Plain 

8 Mesozoic and Paleozoic 

platform rocks 

E;] Terrestrial volcanism 

E:J Structural extension 

[D Trans"ion area 

mJ Accreted terrane 

0 

I 

0 

160 MILES 

I I 

200 KILOI.'ElERS 

GEOLOGIC SETIING 

0 

\., I 

0 

\., 

160 MILES 

I 

Gulf of 

Mexico 

B 

93" 

93° 

Figure 5. Simplified geology (A) and geologic provinces (B) in and adjacent to the U.S.-Mexico border region. Modified from U.S. 

Geological Survey (1970) and Ortega-Gutierrez and others (1992). Geologic province boundaries dashed where uncertain. 

9 
10 NONFUEL MINERAL RESOURCES IN THE UNITED STATES-MEXICO BORDER REGION 

Pacific 

Ocean 

EXPLANATION ' • Quaternary and Tertiary 

volcanic rocks Including small 

areas of Intrusions 

EJ Early Tertiary, Mesozoic, and 

Paleozoic Intrusive rocks 

0 

I 

0 

160 MILES 

I I 

200 KILOMETERS 

Mexico 

'q,.. zt• '--------------------.:_...L ________ _l ____ __J 

Figure 6. Generalized distribution of volcanic and plutonic rocks in and adjacent to the U.S.-Mexico border region. Modified from 

U.S. Geological Survey (1970) and Ortega-Gutierrez and others (1992). 

DATA SOURCES AND COLLECTION 

An initial step of the CIMRI border-region project is an 

inventory of known mines, prospects, and occurrences, 

which are referred to collectively as deposits. Data for each 

site include name , location, commodity, deposit type, and 

geology. CIMRI archives these data in the U.S. Geological 

Survey's Mineral Resources Data System (MRDS), a publicly available computerized data base of mine and occurrence information for nonfuel minerals. MRDS contained 

approximately 5,400 records for deposits within the study 

area prior to CIMRI' s project, and many of these have been 

updated. Most of the existing records were for metal mines 

and occurrences in Arizona, California, and New Mexico. 

CIMRI has added approximately 4,000 additional records 

for the border-region study area; most of these records are 

for Mexico or for industrial mineral sites throughout the 

border region. Data collection is not yet complete, and this 

circular is a progress report; efforts are continuing to collect 

data on metallic and industrial mineral deposits of southeastern California, industrial mineral deposits of northwestem Mexico and southwestern Texas, and sand and gravel 

deposits of Arizona. The reader should be aware that the 

completeness of the information for mines and occurrences 

varies with the area and the available literature. Also, in 

much of Coahuila and Chihuahua, all mineralization 

within 2 kilometers ( 1. 2 miles) of a mine is considered to be 

a single mine or occurrence. 

The total number of border-region records in the 

MRDS as of May 1993 was just under 9,300 for sites 

distributed as shown in figure 7. Figure 8 is a plot of all sites 

in the approximate area of study for which the MRDS 

contains records. In general, the density of data is much 

higher in the United States, although incomplete data sets 

for southern California and southwestern Texas are noticeable. A more detailed discussion of mineral-site data 

collection can be found in Center for Inter-American 

Mineral Resource Investigations (1993). MRDS data for the 

study area are available from Mineral Information Offices 

of the U.S. Geological Survey in digital form or as listings, 

tables, and plots; write to one of the five addresses shown in 

table 2. Table 2 lists additional sources of mineral-resource 

information. 

In addition to mineral-resource information, CIMRI is 

interested in the role of minerals relative to border-region 

issues such as trade, infrastructure development, agriculture 

support, and environmental problems. To help understand 

these relations, CIMRI is also compiling information on 

power generation capabilities, infrastructure, mineral 

exports and imports of the border area, mineral-processing 

plants, environmental cleanup sites, and other topics. 
DATA SOURCES AND COLLECTION 11 

122°30' 36°30',....,.-------~----r--------,r----------r------,-----------, 

21° 

Pacific 

Ocean 

BAJA CALIFORNI 

NORTE ~ 

0 200 MILES 

I I 

0 250 KILOMETERS 

ARIZONA NEW MEXICO 

~ 

TEXAS 

Gulf of 

Mexico 

Figure 7. U.S.-Mexico border region showing the number of Mineral Resources Data System records for sites containing metallic 

minerals only (M), industrial mineral commodities only (I), and both metallic and industrial mineral commodities (B). 

Pacific 

Ocean 

0 160 MILES I I I 0 200 KILOMETERS 

0 

6> 

8 0 

Gulf of 

Mexico 

93° 

21° __________________________________ ~--------------~------~ 

Figure 8. Distribution of all mines, prospects, and occurrences of metallic and industrial mineral commodities in and adjacent to 

the U.S.-Mexico border region for which the Mineral Resources Data System included records as of May 1993. 
12 NONFUEL MINERAL RESOURCES IN THE UNITED STATES-MEXICO BORDER REGION 

Table 2. Some general sources of information on mineral resources of the U.S.-Mexico border region. 

PUBLICATIONS 

Mexico United States 

The mineral economy of Mexico (Martino and others, 1992) Mineral and water resources of Arizona (U.S. Geological 

Survey and others, 1969) 

Economic geology, Mexico (Salas, 1991) Arizona industrial minerals (Phillips, 1987) 

Plano nacional de Ia Republica Mexicana (Mexico Secretaria 

de la Defensa Nacional, 1980) 

Mineral resources of California (U.S. Geological Survey and 

others, 1966) 

Mexican mines (Ord6fiez Cortes, 1986-90) Mineral and water resources of New Mexico (U.S. Geological 

Survey and others, 1965) 

Preliminary deposit-type map of northwestern Mexico 

(Leonard, 1989) 

Mines and mills in New Mexico (Hatton and others, 1990) 

Mexico 

Comisi6n de Fomento Minero 

A v. Puente de Tecamachalco 

No. 25 

Col. Lomas de Chapultepec 

C.P. 11000 

Mexico, D.F. 

Consejo de Recursos Minerales 

Boulevard Felipe Angeles 

SIN KM 93-5 

Col. Venta Prieta 

C.P. 42080 

Pachuca, Hidalgo 

Instituto de Geologia 

Universidad Nacional Aut6noma 

de Mexico 

Estaci6n Regional de Noroeste 

Apart. Postal 1039 8300 

Hermosillo, Sonora 

Industrial rocks and minerals of the Southwest (Austin, 1982) 

Annotated bibliography of mineral deposits in Trans-Pecos 

Texas (Price and others, 1983) 

ORGANIZATIONS 

U.S. Federal 

[All part of the U.S. Department of the Interior] 

Center for Inter-American Mineral 

Resource Investigations 

U.S. Geological Survey 

210 E. 7th Street 

Tucson, AZ 85705 

Minerals Information Offices 

U.S. Geological Survey 

340 North 6th A venue 

Tucson, AZ 85705 

U.S. Geological Survey 

U.S. Department of the Interior 

MS 2647-MIB, Room 2647 

1849 C Street NW. 

Washington, DC 20240 

U.S. Geological Survey 

Mackay School of Mines 

Scrogham Engineering Mines Building 

University of Nevada-Reno 

Reno, NV 89557-()047 

U.S. Geological Survey 

Room 133 

W. 904 Riverside Ave. 

Spokane, WA 99201 

U.S. Geological Survey 

Federal Center MS 936 

Bldg. 20, Rm. B1324 

Denver, CO 80225 

U.S. Bureau of Land Management 

18th & C Streets NW. 

Washington, DC 20240 

U.S. Bureau of Mines 

810 7th Street NW. 

Washington, DC 20241 

U.S. State 

Arizona Geological Survey 

845 N. Park A venue 

Tucson, AZ 85719 

Arizona Department of Mines and 

Mineral Resources 

1502 West Washington 

Phoenix, AZ 85007 

California Division of Mines and 

Geology 

801 K Street, MS12-30 

Sacramento, CA 95814--3531 

New Mexico Bureau of Mines and 

Mineral Resources 

Campus Station 

Socorro, NM 87801 

Texas Bureau of Economic Geology 

Balcones Research Center 

University Station, Box X 

Austin, TX 78713-7508 
MINERAL-RESOURCE DISTRIBUTION 13 

Table 3. Mineral commodities produced within the U.S.-Mexico border region. 

[Data from the Mineral Resources Data System] 

Major 

Copper 

Gold 

Lead 

Silver 

Zinc 

METALS 

Minor 

Iron 

Mercury 

Molybdenum 

Rhenium 

Tungsten 

MINERAL-RESOURCE DISTRIBUTION 

One of the goals of this study is to identify which 

resources occur within the study area and which need to be 

imported to supply border-region industries. In addition, 

minerals that might be exported from the region will be 

identified. The variety and number of occurrences of 

metallic and nonmetallic resources in the border region are 

extensive. These resources include precious and base metals 

and materials used in agriculture, infrastructure development, environmental improvement, and production of 

chemicals. Commodities produced in the study area are 

listed in table 3. Fuel materials (coal, uranium, oil, and gas) 

are prevalent in the border region but are not addressed in 

this study. Metals for producing steel, aluminum, and 

nonferrous alloys occur in minor amounts and are not 

available in the quantity necessary to support an extensive 

industry in the border region. Ferrous metals occur in a 

number of deposits and have supported an integrated steel 

plant at Monclova, Coahuila, in the recent past, but 

increased reserves would be needed to revitalize this plant 

(Martino and others, 1992). A major integrated steel plant 

continues to operate in Monterrey, Nuevo Leon, but is 

dependent on imported ores. 

The distribution of major mines, prospects, and occurrences of gold and silver in the border region is shown in 

figure 9. The sites shown in this figure represent both placer 

and lode deposits where gold and (or) silver were listed 

as major commodities. The distribution of precious metals 

in the study area indicates that the western part of 

the area is more gold rich and that the southeastern part 

of the area is silver dominated. There are no reported 

INDUSTRIAL MINERALS AND MATERIALS 

Major 

Aggregate (crushed stone and gravel) 

Barite 

Bentonite 

Borates 

Celestite 

Clays 

Fluorite 

Graphite (amorphous) 

Gypsum 

Halite 

Limestone (for use in cement) 

Potash 

Pumice 

Sand and gravel 

Sodium sulfate (natural) 

Sulfur 

Zeolites 

Minor 

Building stone 

Diatomite 

Feldspar 

Kaolin 

Magnesia-magnesite 

Mica 

Nitrogen-nitrates 

Perlite 

Phosphates 

Wollastonite 

major gold occurrences in Nuevo Leon, Tamaulipas, or 

Coahuila, although a few small occurrences have been 

reported. Precious metals, gold and silver, were the dominant commodities of interest in the border region until the 

mid-19th century, when lead, zinc, and copper deposits 

began to produce and eventually dominated metal production. In the 1970's and 1980's, gold again became the focus 

of mineral exploration on the U.S. side of the border and 

continues to be the main commodity of exploration interest 

throughout the study area. The change in regulations 

concerning exploration and mining in Mexico in 1990 has 

created an explosion of activity by foreign investors in 

precious-metal exploration in Mexico. Current opinion of 

the potential for undiscovered deposits in northern Mexico 

and the large gap between early exploitation and modem 

exploration indicate that the border region will continue to 

be a source of considerable precious-metal wealth in the 

foreseeable future. 

With the discovery of base-metal deposits (lead, zinc, 

and copper) in the mid-1800's, the resource focus changed 

to the development of lead and zinc industries. The distribution of known mines, prospects, and occurrences where 

copper or lead and zinc are the main commodities is shown 

in figure 10. Lead and zinc deposits appear to be more 

abundant in the eastern part of the border region, particularly in Chihuahua, Coahuila, and Tamaulipas. These base 

metals have played a key role in mineral-resource development in the border region. By World War I, the border 

region had become a significant copper producer and, in 

fact, there was a copper boom spurred by the technology to 

recover copper from large tonnages of low-grade copper 

material. Mexico's copper production grew to be the 11th 
14 NONFUEL MINERAL RESOURCES IN THE UNITED STATES-MEXICO BORDER REGION 

Pacific 

Ocean 

0 

I 

~ 

EXPLANATION 

e Silver 

0 Silver and gold 

0 Gold 

I 

160 MILES 

I 

200 KILOMETERS 

Gulf of 

Mexico 

~. 

21 ~--------------------------------------------~~--------------------~----------~ 

Figure 9. Distribution of major gold and silver mines, prospects, and occurrences in and adjacent to the U.S.-Mexico border 

region. Data from the Mineral Resources Data System. 

122"30' 93' 

36'30' r"""1~------------r-------~--------"T"-----,-----------, 

21° 

Pacific 

Ocean 

EXPlANATION ' • Copper and lead and (or) zinc 

0 Copper 

o Lead and (or) zinc 

0 

I 

0 I 

160 MILES 

I 

200 KILOMETERS 

Gulf of 

Mexico 

Figure 10. Distribution of major lead and (or) zinc and copper mines, prospects, and occurrences in and adjacent to the 

U.S.-Mexico border region. Data from the Mineral Resources Data System. 
MINERAL-RESOURCE DISTRIBUTION 15 

Table 4. Significant industrial mineral commodities used in agriculture, infrastructure, and environmental improvements in the 

U.S.-Mexico border region. 

[Industrial mineral commodities produced in the border region are listed in table 3. Some commodities used in the border region are produced there, 

and some are brought in. Data from the Mineral Resources Data System] 

... G) .CG) 

a ... c ·-CIS 

0 E G) a '! ~ ::l G) • ... C) 

E Q. -§,a > ::::; CJ ·-CIS _, 

AGRICULTURE 

Fertilizers or conditioners X X X 

Feeds 

Chemicals or insecticides X X 

INFRASTRUCTURE 

Cement X X X 

Roads 

Bridges and overpasses X 

Railroads 

Power X 

ENVIRONMENTAL IMPROVEMENTS 

Acid lakes X 

Acid mine drainage X 

Spill cleanup 

Hazardous material transport X 

Noise abatement X X 

Energy efficiency X X 

Waste treatment or containment X X X 

largest in the world by 1992, with nearly all the copper 

coming from the border region, and copper production in 

the United States made it the 2d largest producer in the 

world (Thompson, 1993). Most of the U.S. copper also 

comes from the border region. The U.S.-Mexico border 

region is one of the richest copper provinces in the world. 

Many of the same mineral materials used in agriculture 

are also used for infrastructure development and environmental improvement (table 4). For example, limestone, 

gypsum, light-weight aggregate, and boron (from borates) 

all have applications in these three areas. Many other 

materials are used in two areas. Most of the materials are 

used in agriculture. Figure 11 shows the distribution of 

known mines, prospects, and occurrences of limestone 

(including marble and dolomite), light-weight aggregate 

(including perlite, pumice, vermiculite, and other volcanic 

materials), sand and gravel, and stone used as aggregate or 

building stone. The absence of data points for these materials in Baja California Norte and Sonora in the figure is 

probably a function of incomplete data collection and not a 

.. G) 

a; .t: 

> • G) "iii G) 

CIS .c ... ... I .t: I CIS 

a G) E .s! ... .c • Q. G) 

.. c ~ 0 • • .2 1U ... "go CIS • CIS 0 1U > ... 0 ... CIS~ CIS 0 :; 0 ... ~ c u .c en CL. en al CL. z 

X X X X X X 

X X 

X X X 

X X 

X 

X X 

X 

X 

X X 

X X X X 

X X 

X X 

X X X X X 

result of the geology. The gap in known occurrences of 

these commodities in southern Arizona coincides with an 

Indian reservation adjacent to military lands. These materials, although used mainly in infrastructure development, 

have other uses as shown in table 4. 

Zeolite, gypsum, and diatomite distribution in the 

border region is shown in figure 12. Their applications cross 

several areas of use, but they are generally important to 

environmental cleanup because of their absorbent properties. Lack of known occurrences of these commodities 

outside of Arizona, Nuevo Leon, and Coahuila is a reflection of incomplete data. 

The border region is a leading producer of strontium 

from celestite and fluorine from fluorite, and the distribution of these commodities is shown in figure 13. Included 

on this figure is the distribution of barite, which is used in 

drilling mud. Again, the apparent lack of barite, fluorite, 

and celestite deposits in California, Baja California Norte, 

western Sonora, and western Coahuila is probably a function of the incomplete data. 
16 NONFUEL MINERAL RESOURCES IN THE UNITED STATES-MEXICO BORDER REGION 

122°30' 36°30' ,...,-------~----,-------~-------...,...-----,.---------~ 

Pacific 

Ocean 

EXPLANATION 

o Sand and gravel 

e Limestone 

• Light-weight aggregate 

D Building and crushed stone 

0 

I 

0 I 

160 MILES 

I 

200 KILOMETERS 

~. 

Gulf of 

Mexico 

21°~------------------------------~---------------~-------~ 

Figure 11. Distribution of mines, prospects, and occurrences of construction materials in and adjacent to the U.S.-Mexico border 

region, including sand and gravel, limestone, light-weight aggregate (pumice, perlite, vermiculite), and stone for aggregate or 

building stone. Data from the Mineral Resources Data System. 

Figure 14 shows the distribution of four disparate 

groups of industrial minerals: all clays, evaporite minerals 

(potash and (or) halite), sodium sulfate and sodium carbonate, and sulfur. Again, there are large gaps in the plot of 

occurrences in northern Mexico that are probably due to 

incomplete data. 

Other materials and metals occur in the border region. 

Readers interested in the distribution of commodities not 

included in this publication should contact the U.S. Geological Survey offices listed in table 2. 

DISCUSSION 

Initial compilation of nonfuel mineral-resource data 

has thus far identified approximately 9,300 known deposits 

and occurrences in the U.S.-Mexico border region of 

precious metals, base metals, and mineral commodities 

used in infrastructure, agriculture, and environmental 

improvement. Preliminary assessment of the geological 

terranes implies that further exploration in northern Mexico 

could augment the known deposits of many industrial 

minerals, including zeolites and clays. The low density of 

existing road and railroad infrastructure in parts of northern 

Mexico could impede future resource development, especially the development of low-value industrial minerals and 

bulk construction materials such as aggregate and sand and 

gravel. 

Investment capital for exploration and mining will 

probably accelerate its flow to Mexico. The reasons for this 

include the decreasing land area in the southwestern United 

States open to mineral exploration and exploitation, increasingly restrictive U.S. regulations, the extensive amount of 

land open to mining in Mexico, and favorable Mexican 

investment and mining regulations. Expansion of mining 

activities in Mexico will probably mean increasing flows of 

many minerals and materials from Mexico to the United 

States and Canada. However, known deposits of materials 

for environmental cleanup efforts are limited in northern 

Mexico, and, in the short term, these materials may be 

expected to flow southward. Iron and aluminum alloys will 

also have to be imported into the border region. 

In the future, with increased exploration and financial 

investment, the border region is likely to experience significant growth. As this growth occurs, the demand for 

minerals for industry, infrastructure, housing, agriculture, 

environmental cleanup, and other uses will also increase. 

The ability of the border region to supply many basic 

minerals to industries within its boundaries and outside of 

its boundaries contributes to the prospect of a bright 

economic future. 
Pacific 

Ocean 

~ 

EXPLANATION 

0 

I 

0 

• Diatomite 

o Zeolites 

o Gypsum 

I 

160 MILES 

I 

200 KILOMETERS 

DISCUSSION 

0 oo 

0 

~. 

0 

0 

0 

0 

Gulf of 

Mexico 

17 

Figure 12. Distribution of mines, prospects, and occurrences of gypsum, zeolites, and diatomite in and adjacent to the 

U.S.-Mexico border region. Data from the Mineral Resources Data System. 

Pacific 

Ocean 

EXPLANATION 

0 

I 

0 

• Barite 

o Celestite 

0 Fluorite 

I 

160 MILES 

I 

200 KILOMETERS 

Gulf of 

Mexico 

93° 

~. 

21° ~------------------------------------------------~--------------------~----------~ 

Figure 13. Distribution of mines, prospects, and occurrences of barite, fluorite, and celestite (a source of strontium) in and 

adjacent to the U.S.-Mexico border region. Data from the Mineral Resources Data System. 
18 NONFUEL MINERAL RESOURCES IN THE UNITED STATES-MEXICO BORDER REGION 

Pacific 

Ocean 

EXPLANATION 

• Clays 

0 Halite and (or) potash 

• Sulfur 

C Sodium carbonate or sodium sulfate 

0 

I 

0 I 

160 MILES 

I 

200 KILOMETERS 

• t. 

g 0 • 0 

•• • 

'·· • 0. 0 

0 

0 

Gulf of 

Mexico 

21°--------------------------------------~~·~----------------~L_ ______ __J 

Figure 14. Distribution of mines, prospects, and occurrences of clays, evaporite (halite or potash), sodium carbonate or sodium 

sulfate, and sulfur in and adjacent to the U.S.-Mexico border region. Data from the Mineral Resources Data System. 

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Conference, Oct. 7-9, Guidebook, p. 285-293. 

Austin, G.S., comp., 1982, Industrial rocks and minerals of the 

Southwest: New Mexico Bureau of Mines and Mineral 

Resources Circular 182, 111 p. 

Bachman, G.O., 1965, Mineral industry in New Mexico, in U.S. 

Geological Survey and others, Mineral and water resources of 

New Mexico: U.S. Congress, 89th, 1st session, Senate 

Committee on Interior and Insular Affairs, Committee Print 

(New Mexico Bureau of Mines and Mineral Resources 

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93-532, 33 p. 

Clark, K.F., Foster, C.T., and Damon, P.E., 1982, Cenozoic 

mineral deposits and subduction-related magmatic arcs in 

Mexico: Geological Society of America Bulletin, v. 93, p. 

533-544. 

Diaz-Unzueta, Raul, 1986, Geology and mineralization of La 

Encantada silver-lead district, Coahuila, Mexico, in Clark, 

K.F., Megaw, P.K.M., and Ruiz, J., eds., Lead-zinc-silver 

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field and mine excursions, November 13-17, 1986: Society 

of Economic Geologists, p. 311-324. 

Engineering and Mining Journal, 1905, The Mexican "Free 

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Forrester, J.D., 1969, The mineral industry of Arizona, in U.S. 

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Arizona: U.S. Congress, 90th, 2d session, Senate Committee 

on Interior and Insular Affairs, Committee Print (Arizona 

Bureau of Mines Bulletin 180), p. 21-33. 

Gerald, R.E., 1984, Geological resources utilized by the prehistoric society of Casas Grandes, northwestern Chihuahua, in 

Kettenbrink, E.C., Jr., ed., Geology and petroleum potential 

of Chihuahua, Mexico: West Texas Geological Society Publication 84-80, p. 213-215. 

Griggs, Jorge, 1907, Mines of Chihuahua: Chihuahua City, 

Mexico, 384 p. 

Hatton, K.S., Childs, M.B., Barker, J.M., King, R.S., and 

Bolton, R.G., comps., 1990, Mines and mills in New 

Mexico: Santa Fe, New Mexico Energy, Minerals and 

Natural Resources Department, Mining and Minerals Division, 50 p. 

Heylmun, E.B., 1988, The Golden Triangle, Sonora, Mexico: 

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Lacy, J.C., 1987, Early history of mining in Arizona-Acquisition of mineral rights 1539-1866, in Canty, J.M., and 

Greeley, M.N., eds., History of mining in Arizona: Tucson, 

Mining Club of the Southwest Foundation, p. 1-12. 
REFERENCES CITED 19 

Leonard, K.R., 1989, Preliminary deposit-type map of northwestern Mexico: U.S. Geological Survey Open-File Report 

89-158, 362 p., scale 1:1,000,000. 

Martino, Orlando, Machamer, Jerome, and Torres, Ivette, 1992, 

The mineral economy of Mexico: U.S. Bureau of Mines 

Mineral Perspectives MP 1-92, 150 p. 

Mexico Secretaria de Comunicaciones y Transportes, 1990, Mapa 

turistico de carreteras [Tourist road map]: [Mexico City?] 

Direcci6n General de Planeaci6n de la Secretaria de Comunicaciones y Transportes, scale 1:3,500,000. 

Mexico Secretaria de la Defensa Nacional, 1980, Plano nacional 

de la Republica Mexicana: Mexico City, Mexico, Secretaria 

de la Defensa Nacional, scale 1:1,000,000. 

Officer, J.E., 1991, Mining in Hispanic Arizona-Myth and 

reality, in Canty, J.M., and Greeley, M.N., eds., History of 

mining in Arizona, Volume II: Tucson, Mining Club of the 

Southwest Foundation and American Institute of Mining 

Engineers (Tucson Section), p. 1-12. 

Ord6fiez Cortes, J.E., ed., 1986-90, Minas Mexicanas [Mexican 

mines]: American Institute of Mining, Metallurgical and 

Petroleum Engineers, Seccion Mexico, and Society of Economic Geologists, 5 v. 

Ortega-Gutierrez, F., Mitre-Salazar, L.M., Roldan- Quintana, J., 

Aranda-Gomez, J., Moran-Zentendo, D., Alaniz-Alvarez, 

S., and Nieto-Samaniego, A., 1992, Carta geologica de la 

Republica Mexicana [Geologic map of Mexico]: Consejo de 

Recursos Minerales de Mexico and Instituto de Geologfa de 

la UNAM (Universidad Nacional Aut6noma de Mexico), 

scale 1:2,000,000. 

Pearson, B.T., 1974, Historical notes, in Geologic field trip 

guidebook thru the States of Chihuahua and Sinaloa, Mexico: 

West Texas Geological Society Publication 74-63, p. 149-

150. 

Phillips, K.A., 1987, Arizona industrial minerals (2d ed.): Arizona Department of Mines and Mineral Resources Mineral 

Report 4, 185 p. 

Price, J.G., Henry, C.D., and Standen, A.R., 1983, Annotated 

bibliography of mineral deposits in Trans-Pecos Texas: Texas 

*U.S. G.P.0.:1993-301-077;80044 

University Bureau of Economic Geology Mineral Resource 

Circular 73, 108 p. 

Rand McNally, 1989, Road atlas, United States, Canada, Mexico 

(65th ed.): San Francisco, Rand McNally and Company, 

129 p. 

Ruiz, Joaquin, Sweeney, Robin, and Palacios, Hugo, 1986, 

Geology and geochemistry of Naica, Chihuahua, Mexico, in 

Clark, K.F., Megaw, P.K.M., and Ruiz, J., eds., Lead-zincsilver carbonate-hosted deposits of northern Mexico, guidebook for field and mine excursions, November 13-17, 1986: 

Society of Economic Geologists, p. 169-178. 

Salas, G.P., ed., 1991, Economic geology, Mexico, v. P-3 ofThe 

geology of North America: Boulder, Colo., Geological Society of America, 438 p. 

Thompson, Martin, 1993, Copper: Metals & Minerals Annual 

Review, 1993, p. 41--47. 

U.S. Department of Energy, Western Area Power Administration, 

1992, Principal power facilities, western United States: 

[Washington, D.C.] U.S. Government Printing Office, 1 p., 

approx. scale 1:10,000,000. 

U.S. Geological Survey, 1970, The national atlas of the United 

States of America: Washington, D.C., 417 p. 

U.S. Geological Survey, Arizona Bureau of Mines, and U.S. 

Bureau of Reclamation, 1969, Mineral and water resources of 

Arizona: U.S. Congress, 90th, 2d session, Senate Committee 

on Interior and Insular Affairs, Committee Print (Arizona 

Bureau of Mines Bulletin 180), 638 p. 

U.S. Geological Survey, California Division of Mines and Geology, and U.S. Bureau of Mines, 1966, Mineral resources of 

California, pt. 1 ojMineral and water resources of California: 

U.S. Congress, 89th, 2d session, Senate Committee on 

Interior and Insular Affairs, Committee Print (California 

Division of Mines and Geology Bulletin 191), 450 p. 

U.S. Geological Survey and others, 1965, Mineral and water 

resources of New Mexico: U.S. Congress, 89th, 1st session, 

Senate Committee on Interior and Insular Affairs, Committee 

Print (New Mexico Bureau of Mines and Mineral Resources 

Bulletin 87), 437 p. 

SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS 

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