History of the Los Cerrillos Mining District

By Homer Milford

This material was originally published
by the New Mexico  Abandoned Mine Land Bureau
Reports 1994 - 2 and 1996 - 1

Homer Milford is the former Environmental Coordinator of the Abandoned Mine Land Bureau, the State  of New Mexico Energy Minerals and Natural Resources Department.

Acknowledgments: I would like to thank Robert Eveleth of the New Mexico Bureau of Mines and Mineral Resources for his assistance with references and information, and also Rick Hendricks of the Vargas Project at the University of New Mexico for his comments on the Vargas and Rodriguez Cubero period. I would also like to thank Dede Snow for information on Analco, and recognize posthumously the contribution of Verne Byrne and Michael O'Neil in continuing the mining tradition of the area, but especially for their preservation of the Territorial mining district record  books.



Historical Importance of the Cerrillos Mining District

In the 1960s, a survey of potential "Historic sites or Districts" in the United States was conducted by the National Park Service. One of the results was a list of 172 sites in the western United States as "Historic Districts Eligible for the Registry of National Historic Landmarks", and the"Cerrillos  Mining District" was one of the sites judged eligible (Ferris, 1967). Following this early effort,  the Museum of New Mexico staff tried in the early 1970s to have the Cerrillos  Mining District listed as a "National Historic District". The effort failed to  get Federal approval. In spite of the fact that it is not listed on the National Register of Historic Places, it does have national historical significance. The Pueblo Indians mined turquoise in the district before 800 AD and one theory attributes the development of the Chaco culture to their control of the Cerrillos Turquoise mines. By the 1300s, Pueblo Indians were mining lead in the area for the metallic glazes on their pottery. When European settlers arrived in 1598, it was the earliest European mining area in the United States.

Considering that numerous mining towns and districts are on the national list, it is unreasonable that the "Oldest Mining District in the U.S." is not listed. It was first prospected in 1581 and had a number of active mines almost a decade before the first English colonist landed at Jamestown.

This area is historically significant for reasons other than just being the oldest mining district in the United States. The miners of Los Cerrillos may deserve recognition as the founders of Santa Fe. They may have started a mining camp on the south side of the Santa Fe River about 1600. The solely Spanish community north of the river was not founded until four or five years later, in 1605. The silver produced in the Cerrillos District was probably a significant component of the 17th Century New Mexico economy. In northern New Mexico other than Santa Fe,  the Los Cerrillos settlement was the only community to successfully resist the initial revolt of 1680. In 1695, Governor Vargas founded the Real de Los Cerrillos,  which is tied for being the third to fifth oldest official European Community in New Mexico history, to service the mines of Los Cerrillos. Real de Los Cerrillos is the "oldest official mining community in the history of the United States".  Governors Oñate, Vargas, and Rodríguez Cubero are the only known Spanish Governors to be involved personally with mines in the district, but at least two U.S. Territorial Governors, Lew Wallace and L. Bradford Prince, also owned and operated mines there. The history of this district has not been common knowledge in the past and only small segments of it are in books written on either New Mexico or its mining history.

Past studies of the Cerrillos Mining District

Although a great deal has been written in the popular press over the years about  the Cerrillos Mining District, relatively few serious studies of the area have been published, and considerable confusion still exists about its history.

Twentieth-century studies have started the U.S. Period History of the area with the mining rush of 1879-80 reported by Hayward (1880) and the local and national press of the time, and ignored the mining of the 1860s and 1870s. Past writings have concentrated on the eastern portion of the district and ignored the western area. Hayward (1880) covered the entire area and listed a number of mines as "Old Spanish". The 1800's newspaper accounts tended to promote mines in the eastern part of the district and published archaeological work has also been confined to that area. Thus there is a tendency to think of the important part of the Cerrillos Mining District as being the southeastern part of the district with its old Spanish mine, the Mina del Tiro, and major U.S. Period mines such as the Cash Entry. Turquoise Hill in the northeastern part of the district has also attracted attention. The history of  the western part of the district has been largely ignored. Some of the notable researchers of the mining history of the general area are Joan Mathien, Albert  Schroeder, John Townley, and A. Helen Warren. A previous Abandoned Mine Land Bureau project in the eastern part of the district funded a historical report by Levine and Goodman (1990) that collected a lot of historical data from the above authors, but followed the old precept that there was little or no significant mining during the colonial period.

Disbrow and Stoll (1957) authored the only detailed study of the western part of the district, but they did not go back before 1879 in their history. The mines reopened by Dr. Enos Andrews in the western area in 1872 may be mines associated with the 1695-1696 mining period. These mines are only half as far from Alamo Creek, the probable location of the Spanish mining camp of Real de los Cerrillos, as Arroyo de las Minas where the Mina del Tiro is located. It is a portion of this western part of the district which is the subject of this report.

Brief Time Line for the Cerrillos Hills Area

  • circa   700 - First turquoise mining by Pueblo Indians.
  • circa 1150 - First separate villages, "mining  camps" for miners and refiners of turquoise in the Cerrillos Hills.
  • circa 1300 - First lead mining by Pueblo Indians.
  • 1581 - First European prospecting of the Cerrillos Hills area which was called the Sierras of San Marcos from 1591 to late 1700s.
  • 1601 - First silver mines started and first smelters built by Vicente de Zaldivar and others in this area. The miners may have started a mining camp (Analco?) 6 leagues
     from the mines which could be the first colonial settlement at Santa Fe.
  • 1632 - First reported estancia (ranch) in the La Cienega area.
  • 1630s-1643 - Diego Marqués starts a ranch north of the hills in the Alamo Creek - Cienega area.
  • 1660 - Earliest located reference to Los Cerrillos as a place name for Marqués's ranch two leagues from San Marcos Pueblo.
  • 1680 - Though silver objects were later reported as common in New Mexico prior to 1680, the only located record of mining in 1680 is Roque Madrid I's lead mine.
  • 1680 - Residents of Los Cerrillos area assemble at hacienda of Bernabé Marqués in Los Cerrillos to defend themselves and then withdraw to Santa Fe and then to El Paso.
  • 1680-1693 - Alonzo Catiti Marquéz has a leadership role in the revolution. Except for a few military expeditions, the revolution kept Europeans and their Native American allies out of northern New  Mexico.
  • 1693 - Reconquest of New Mexico and promotion of mines by Vargas.
  • 1695 - Three silver mines were active in the hills and Vargas founded the official Mining Camp, "Real de Los Cerrillos".
  • 1696 - New revolt forces abandonment of Real de Los Cerrillos.
  • 1697-1703 - Governor Rodríguez Cubero acquired the "Santa Rosa Mine" and shipped silver to Mexico City.
  • 1709 - "Santa Rosa Mine" previously belonging to Governor Cubero claimed by Ulibarrí.
  • 1750 - Applicant for a Los Cerrillos Land Grant  presents a forged 1692 Land Grant supposedly given to the man who was the mayor of "Real de Los Cerrillos" defining Los Cerrillos as the Alamo Creek area north of the hills. Applicant also states that ruins are still visible in the area, which must have been the ruins of the mining camp.
  • 1830 - "Santa Rosa Mine" rediscovered and worked by Alvarado.
  • 1872 - Area of Santa Rosa Mine purchased from Government by Dr. Andrews and he reopens it and the Ruelena Mine.
  • 1879 - Galisteo and Cerrillos Mining District rush starts and modern development of the district begins.
  • 1880s - Mining rush plays out and activity subsides in Hungry Gulch. There is little activity until about 1900 when mining shifted from silver-lead to lead-zinc ore.
  • 1900-1956 Only sporadic mining in Hungry Gulch, mainly during World War I and II, and government strategic metal stockpiling when zinc and lead prices were high.
  • 1956 - last known mining in Hungry Gulch area.
  • 1970s - last major effort to start a new mine in the Cerrillos District failed to get government approval.
  • 1975 - last known operation of a mine in the Cerrillos District.

This Abandoned Mine Land Bureau Project covers a small portion of the western part of the district, called in the late 1800s, "Hungry Gulch".  One objective of this project was to collect information on the mines of the Hungry Gulch area and to bring their importance and that of "Real de Los Cerrillos" to attention.

Of the Spanish metal mines whose Spanish names and locations have survived, only the Mina del Tiro has been written about in this century. The proposed leach mining in the southeastern part of the district, T 15N, R 8E, sections 7 & 8, in the early 1970s by Occidental Minerals  Corporation, led to an archaeological survey of the area (Warren, 1974), and also led to efforts to salvage information on Pueblo and Spanish mining in that area (Karkins, 1971, 1972) before leach mining started. The Albuquerque Archaeological Society did two summers' work at the Bethsheba Mine, a U.S. period mine name from Hayward (1880). Only preliminary reports have been published (Sundt, 1973, Grigg and Sundt, 1975), but Richard Bice (Bice, 1993) is working on a final report. The Mina del Tiro (Hawk-eye shaft) was also partially excavated, and Warren (1974) gave some results of that excavation but no report has been published. Nineteenth Century promotion and the work of Warren and others in the southeast area has led to the general assumption that the "Arroyo de las Minas" area with the Mina del Tiro was the most important area of Spanish mining in the Cerrillos Hills.

Though not discussed in writings of this century, two of the mines in Hungry Gulch covered by this report are probably the sites of richer and more important Spanish silver-lead mines than the Mina del Tiro.

In 1695, Governor Vargas founded the Real de Los Cerrillos, an official mining  camp, in the vicinity of what we call Alamo Creek. This is the only official Spanish Period mining camp that historical documents have been located for in New  Mexico. This mining camp, which also ranks as the third to fifth oldest official European community in New Mexico, has been ignored in New Mexico history. Its name was chosen in 1990 for this project to try to revive its history along with two mines in this project which may date from that period. Hopefully, the Vargas Project at the University of New Mexico will bring the mining camp to public attention when they release Vargas's 1695-96 Journals. They anticipate publication of these journals in 1996 on the 301st anniversary of Real de Los Cerrillos. The two mines that probably date from the Vargas era are the Santa Rosa and the Ruelena, which, according to 1870's reports, had richer silver ore than the Mina del Tiro.


Nature of Cerrillos Silver Deposits

The silver deposits of Parral are in many ways similar to those of Cerrillos. The silver ores of Parral were formed in nearly vertical veins associated with Tertiary vulcanism (West, 1949, p. 17), as are those of Cerrillos. In Parral there were some deposits that were nearly lead-free silver sulphide (argentite) as well as silver-lead sulphide (galena) veins. In Cerrillos only the silver-lead sulphide (galena) were noted at the time of the first mineral descriptions of the area in the 1870s and 1880s. If argentite existed at Cerrillos it was not reported in the late 1800s. The mines of Santa Barbara developed prior to the colonization of New Mexico in the 1500s had only the galena type ores found at Los Cerrillos.

A peculiar characteristic of silver ore deposits is the occurrence  of a pronounced oxidized zone of mineral enrichment above the ground water  table. ... The supergene enrichment of sulphide ore by descending surface waters  was one of the most significant factors affecting early colonial silver mining.  (West, 1949, pp.17-18).

In nearly vertical veins such as Cerrillos and Parral over millions of years the sulphide ore above the water table was oxidized by oxygen in the descending surface water. This liberated the silver ions from the sulphur, allowing the silver to go into solution and be carried downward in the vein by the surface water. The silver ion then precipitated out of solution at the water table resulting in  zone of silver enrichment. This so-called "supergene enrichment of sulphide ore  veins" created a zone of silver enrichment around the water table. It was the enriched portion around the water table that early colonial miners exploited. In Parral the water table was at a depth of three to four hundred feet [91.4 to 121.9 meters] and in Cerrillos around 100 feet [30.5 meters].

This is why extensive drifts at a depth of around 110 feet [33.5 meters] (the water  table), left by the Spanish miners were discovered in the 1800s in both the Mina del Tiro and Santa Rosa Mines. The Spanish miners had worked and removed most, if not all, of the zone of silver enrichment. The only exception would have been the Territorial mines developed on veins not exploited by Spanish miners, of which there were very few in Cerrillos. The Territorial mine Our Georgie (aka Tom Payne) and possibly the Marshal Bonanza may have been on veins not discovered by the Spanish miners. The 19th Century assays, with the exception of those reported by Raymond (1872, 1874), are not reliable, and no production figures indicating the quality of the ore have been located prior to 1905. The only evidence available on the silver content of the enriched zone ores of Los Cerrillos are a few circa-1600 assays, and the 1870-1880 assay claims of 80 to 200 ounce per ton [2,268.0 to 5,669.9 grams per 0.9 tonne] silver.  Below the zone of enrichment, the galena (lead sulphide ore) has relatively low silver content. Parral mining declined by the late 1700s as the zones of enrichment were exhausted, and this was probably also the case for the Cerrillos mines in the 1700s.

 Mining in both areas was revived in the late 1800s due to lower costs associated with the arrival of the railroads in both areas. Both Parral and Cerrillos saw a major revival around 1900, when the non-enriched parts of their veins became profitable as sources of lead-zinc ore. The silver deposits of the Real (mining  camp) of Parral, discovered 50 years after Cerrillos in 1631, suffered from its remoteness and it is 1/3 closer to Mexico City than Cerrillos. Both Parral and Cerrillos suffered from the high cost of transportation during most of their history.


Cerrillos Myths


Once an idea becomes widely accepted and is repeated for decades or centuries, new writers of history accept the idea without question. After decades of acceptance by the best scholars in an area of study, only the foolish challenge an accepted concept. However, it is impossible to discuss the mining history of Cerrillos without questioning some myths that have been accepted for the past  century. An attempt was made, perhaps unsuccessfully, to give enough information to start the process of changing three myths associated with Los Cerrillos without overburdening this report. Though these myths will not die with this report, at least the seeds of change are sown and future writers will feel more inclined to  challenge them.

One, that the modern railroad-mining town of Cerrillos is or was close to the Spanish Los Cerrillos. Two, that there was no Spanish mining in New Mexico until after 1725, and three, that there was a significant amount of gold in the Cerrillos Hills. A fourth myth, that Spanish use of forced Pueblo Indian labor in the mines of the Cerrillos Hills was the cause of the 1680 Pueblo Revolt, has been challenged since Bandelier's Final Report in 1890 and was discussed in the AML Turquoise Hill Report  (AML, 1994).

All four of these myths are not supported by contemporary records. As F. Stanley (1964, p.3) said in his little book, "The Cerrillos, New Mexico Story", "The legends of Cerrillos are more numerous than those of Santa Fe." These legends are not confined to popular press publications for the tourist industry like "Living Legends of the Santa Fe Country"  (Bullock, 1972) which probably deliberately used misquotes to make interesting reading. In one form or another, one or more of these myths can be found in most government and scholarly publications of this century discussing the Cerrillos area (for example: USGS, 1977, p. 141 and Howard, 1967).

A Different Perspective on Juan de Oñate

Most of the documents that have survived from the Oñate Period are those written by the two Viceroys or their officers in Mexico City. They served between the two terms of Viceroy Luís de Velasco (1595-1607). They tend to leave the reader with the impression that Juan de Oñate knew little about mining and accomplished very little in New Mexico. This appears to be a misconception that will in time be corrected.

Juan de Oñate was very knowledgeable about mining and was recognized by the King of Spain in 1624 as a leading mining expert of his time  (Beerman, 1979). King Philip IV asked  Oñate to evaluate all the mines and mills in Spain and to recommend new laws and ordinances for improving them. The results of that study were published in 1625, and are the first book on mining written by a resident of what was to become the U.S. The Viceregal documents paint Oñate as a novice regarding mining while he was in New Mexico, but that was part of the overall effort to discredit his administration.

Juan de Oñate and Vicente de Zaldivar were both second generation members of major silver mining families. They both grew up supervising and working in and around family silver mines, and it was the profits of these same family silver mines that funded and made possible the colonization of New Mexico. The "silver aristocracy"  of northern New Spain had financed the exploration and colonization of Nueva Viscaya between 1563 and 1572, and New Mexico was a continuation of this tradition. Both men had extensive experience in the development of silver mines and the construction and running of silver refining mills before coming to New Mexico.  After leaving New Mexico in 1610, both men returned to Zacatecas and revitalized their silver mines there. Oñate paid 129,454 pesos in the 10% severance tax (Simmons, 1991, p. 185) in the decade after he left New Mexico. Vicente de Zaldivar reportedly was so successful in running his families silver mines and mills after his return from New Mexico that he made three million pesos profit during the next decade (Simmons, 1991, p. 186).

A New Spain tribunal in 1614 found Oñate guilty of some of the charges brought against him by the 1601 New Mexico deserters. In 1621, Juan de Oñate went to Spain to clear his name of the various charges. The Spanish Government recognized his great mining expertise and in 1624 made Oñate the Royal Mine  Inspector for the mines in Spain. The king directed Oñate to tour all the major mines of Spain and write a report on how the mines and production could be improved. King Philip IV even gave Oñate a special Royal privilege of  wearing a uniform during his mine inspections (Royal Cédula, sold by Maggs Brothers to a private collector). The results of Oñate's study were incorporated into a new a new set of laws and ordinances for the operation of mines and were published in 1625. The title is very long, and though the product of other members of the Real junta de Minas it gives Oñate the major credit for the New Laws and Ordinances for improving the operation mines and refiners. (The cover page of the "Leyes y Ordenanzas")  The 1625 edition of "Leyes y Ordenanzas" for mines even has a flowery biography of Juan de Oñate in the introduction written by Oñate's secretary (Simmons, 1991, p. 193).

Juan de Oñate was not just the first governor of New Mexico, with a minor  and totally unsuccessful interest in mining as most books and articles tend to indicate. With the exception of Oñate's effort to create a new Viceroyalty of New Mexico, north of New Spain, he devoted his entire life to mining. He grew up in silver mines, successfully managed them before and after being in New Mexico, and rewrote the laws and ordinances on mining for the kingdom of Spain. He even died while still continuing his study of the mines of Spain at the silver mining camp of Guadalcanal (Beerman, 1979). He did not miraculously stop silver mining when he crossed a line that would be drawn on the map two and a half centuries later. Juan de Oñate deserves recognition  along with Vincente de Zaldivar as the premier (first great) miner of what centuries later would become the United States.

Juan de Oñate was the first resident of what is now the United States to  write (or rewrite) a set of laws and ordinances to regulate mining (1625) over two hundred years before any other resident of the U.S. attempted the task.

If American (U.S.) mining is to trace its ancestry, it should not stop with the novice California gold prospectors of 1849, or the novices of Georgia and the Carolinas of the 1790s. These individuals were preceded by lead miners in New England and other British colonists in the 1600s. However, the European mining tradition started in the U.S. with the opening of the silver mines in the Cerrillos Hills in 1601. The actual miners were probably genízro (Tlascalans) and the superintendent was Vincente de Zaldivar at the request of, and possibly under the direction of, Juan de Oñate.  Both men were immediately very successful and made new fortunes operating silver mines south of the border after they left New Mexico, and probably had a lot more success in New Mexico than surviving records indicate.





The Pueblo Indians started mining turquoise in the Cerrillos Hills around 700 AD, and by the 1200s it was the major export of New Mexico, with separate mining camps  (small pueblos) in the hills. There is a yet unproven theory that Cerrillos turquoise was the economic base for the development of Classic Chaco culture.  The history of turquoise mining was discussed in the AML-Turquoise Hill Report (1994) and will not be discussed in this report.

The Pueblo Indians started using lead glaze on their pottery about 1300. Though there is lead float or nuggets around lead veins just as there are gold nuggets around gold veins, eventually the Indians had to dig or mine to get the lead for their pottery. The major lead glaze producing pueblo was Tonque (Warren, 1969) which is east of San Felipe Pueblo, though other Rio Grande Pueblos also produced lead glaze pottery.  "... the Pueblo Indian was the first prospector and miner in the Cerrillos district. Potsherds dating as early as A.D. 1325 have been found in underground lead mines. ... Dozens of prehistoric lode mines have been recorded in the Cerrillos district and two of these have been excavated partially."  (Warren and Weber, 1979, p. 7).

The company exploring the possibility of leach mining of the southeastern part of the district in 1970 financed archaeological recording (Warren, 1974) and spurred efforts to salvage information (Karklins, 1971, 1972)  by excavation before that area was destroyed (Sundt, 1971, Warren, 1974). Sundt (1971) reported pottery types found in the excavation of a filled-in prehistoric trench mine on the 1879 Bethsheba Claim of Maddux and Smith. A final report has not been published, but tentative tree-ring dates from three different logs from the mine and a platform above it are 1462, 1832 and 1908  (Bice, 1993). Its Laboratory of Anthropology (LA) number is (LA 5031). Pottery shards were dated from 1425 to post-1600 with  84% of the pottery being from San Marcos Pueblo. The trench mine at the time of the preliminary report (Sundt, 1971) had only been excavated to a depth of 4 meters (12 feet) but later went to 25 feet [7.6 meters] without reaching the bottom of debris.

Sundt (1971) is the only published excavation of a pre-historic mine in the area, though Warren (1974, p. 25) gives some information on the excavation at Mina del Tiro and her survey of the southeast area.

"... The 'thin mantle of rocky debris" which (Disbrow and Stoll (1957: 48) found on the apexes of many veins is undoubtedly the backfill, or tailings, of the prehistoric Indian miner.

The prehistorically worked lead veins in the survey area include Mina del Tiro (M1), Bethsheba (M6), the U.S. Grant (M9), the L. C. Cloury (M10), the Ethel shaft  (M25), the Helena (M28), the Southwestern (M54), the "chimney" mine (M57), the Bonanza (M58), the J. A. Logan prospects (M63), the Globe veins (M66), and the Stillman vein (M68).

The most spectacular of the prehistoric lead mines is Mina del Tiro, which was mined prehistorically for 1800 feet [548.6 meters] along the vein outcrop, and to as yet unknown depths. ... Potsherds associated with the Pueblo mines are glaze decorated and, as at the turquoise mines, many were used in some part of the mining or refining process. Most of the glazes found are prehistoric and are from the San Marcos Pueblo, but some late glazes produced during the 17th century Spanish Colonial period also occur. These could have been brought to the area by either the Pueblo or Spanish miners.

Stone tools used in the lead mines are very similar to those found at the turquoise mines. Proportionately there seem to be more anvils at the lead mines. Occasionally, a non-utilized notched or grooved axe or maul will be found at a workshop area, indicating that workshops may have been used for more than the refining process. Refining areas located on the edge of the lead vein have been  found. These include hearths, miscellaneous stone tools, and discarded fragments  of lead ore and galena "dust". Debris from the refining of the potter's ore was often used to backfill the vein that had been mined out."  (Warren, 1974, p. 25)

The pueblo's major sources of lead were probably the Cerrillos Hills, the Placitas  area at the north end of the Sandias, and possibly the San Mateo Mountains. There  is conclusive archaeological evidence that the Pueblos were mining lead as well as  turquoise in the Cerrillos area centuries before the arrival of Europeans.




 The records left by the Coronado Expedition to New Mexico in 1540-42 do not  describe a visit to any site that fits the description of the Cerrillos Hills or the pueblo one league east of them, San Marcos Pueblo. The Coronado Expedition did record the presence of galena (lead ore) in several pueblos and the use of lead glazes on the Pueblo pottery.

The first Spanish explorers to visit the area of whom we have a record are the Rodríguez-Chamuscado Expedition of 1581. They called San Marcos Pueblo by the name of Malpartida (Bad Parting) and said they found mineral deposits one league (2.6 to 3.4 miles,) from the pueblo (Hammond & Ray, 1927, p. 342). Two soldiers in the expedition, Philepe (or Filipe) de Escalante and Barrando, later testified that they found 11 veins of silver but did not specify the location in New Mexico.  However, as Oñate 17 years later called the mines he visited in the Cerrillos Hills "Escalante's mines" (Minas de Escalante), the silver veins of the Cerrillos Hills must have been some that Escalante sampled in 1581. The 1581 expedition took samples from only three of the veins they discovered. Bolton (1930, p. 157) translates the reported assays of the three samples. One was half silver, one contained 20 marks (taking 1 mark as about 8 ounces [226.8 grams] then around 160 ounces [4,535.9 grams]) per quintal (quintal = hundred pounds [45.4 kg] or 3,200 oz. per ton [90.7 kg per 0.9 tonne]), and one contained 5 marks (about 40 ounces per 100 pounds [1.1 kg per 45.4 kg] or 800 ounces per ton [2.3 kg per 0.9 tonne]).

These are very high results and possibly exaggerations, but hand-picked ore could have been of that quality. The best ores left in the old Spanish silver mines of the Cerrillos Hills three hundred years later were about 150-200 ounces [4.3-5.7 kg] of silver per ton. Thus, Philipe de Escalante and his companions were the first Europeans that we know for certain prospected the Cerrillos Hills and sampled its silver ores. Their good results were probably a major reason for Escalante's return in 1598 with Oñate.

The Espejo Expedition of 1583 also visited the Cerrillos area and reported finding antimony (galena or silver-lead ore) near San Marcos Pueblo. The Castaño de Sosa Expedition of 1591 gave San Marcos Pueblo the Spanish name by which it has continued to be known. Some members of the Castaño de Sosa party found the mineral ores of the Cerrillos Hills so promising that they stayed in the San Marcos area and made assays showing silver while Castaño de Sosa explored the rest of New Mexico (Schroeder and Matson, 1965, p. 157).

Semi-Autonomous Colony Period,  1598-1610

The original charter given to Juan de Oñate by Viceroy Louis de Velasco (viceroy of New Spain, 1590-1595), and approved by the Crown, gave Oñate autonomy from the colony of New Spain and the right to explore and colonize all of North America north of New Spain except Florida. However, Velasco's successor, Gáspar de Zuñiga y Acevedo, Conde de Monterrey (viceroy of New Spain, 1595-1603) reduced that autonomy from New Spain without crown approval prior to the actual colonization in 1598. This semi-autonomous status existed only during Juan de Oñate's (1598-1608) and his son Governor Cristóbal de Oñate's (1608-1610) rule of  New Mexico. There was extensive mineral exploration and the first "significant"  European mining occurred in New Mexico during this period. Of the records that have survived from this period, virtually all first hand reports on mineral  development in the Cerrillos Hills are from 1600 and 1601.

The first colonists reached San Gabriel, the site chosen for the capitol five miles [1.7 km] north of Española, on July 18, 1598. Two days later, Oñate left for his first reconnaissance of the Pueblos of the Galisteo Basin and stopped at San Marcos and went further south before returning.  Oñate wrote, "On the 26th (July 26, 1598) we returned ... and spent the night at San Marcos ... . Ore was extracted there from the mines called Escalante" (Hammond & Rey, 1953, p. 321).  Thus, within 9 days of the arrival of the first group of colonists at the future capitol of the new colony, the first silver ore was extracted from the Cerrillos Hills. Escalante apparently showed Oñate the mines of the Cerrillos Hills that he sampled 17 years earlier and that is why Oñate referred to them as the "mines of Escalante" (Hammond & Rey, 1953, p. 321). Escalante was killed four months later by the Acomas, along with Vicente de Zaldivar's brother, Juan, in the famous Acoma revolt of December 4, 1598, so any mining he did was of short duration.  Just three years later New Mexicans testified that Juan Zaldivar was the first to mine there, rather than Escalante.

On March 2, 1599, Oñate sent the viceroy a summary of his mining and other discoveries and samples of the minerals that had been discovered (Bancroft, 1889, pp. 147-148).  Juan de Oñate and a major portion of the colonists, both European and Tlascalan, were from Zacatecas and they and their fathers had been silver miners before coming to New Mexico. Thus, their interest and experience had been in silver mining and as far as is known, it was silver deposits, not gold, that they mainlys looked for and tried to develop in New Mexico.

Vicente de Zaldivar de Mendoza, was the first known developer of mines in the Cerrillos Hills. According to the testimony of Baltasar Martinez, and others, there were only about 80 Spanish males in New Mexico on December 23, 1600  (Hammond & Rey, p.837). The number of Spanish, even before a large group of colonists fled in 1600, was well below 200 and most of them were probably occupied in Oñate's explorations and other duties.  Thus, except for short periods, the Tlascalans were probably the major source of skilled miners available in the colony for working mines during the first years.

Juan de Oñate wrote a letter on March 22, 1601 to his brothers (one of whom was the official in charge of the procurement of mining supplies for all of New Spain) and other relatives in which he discussed the mines of New Mexico.  Hammond and Ray (1953, pp. 619-622) located a summary prepared by a Vice regal bureaucrat in Mexico City titled "True Report Drawn from the Letters, Statements, and Papers which Governor Don Juan de Oñate Enclosed with His Letter of March 22, 1601, Addressed to His Brothers and Relatives". Hammond and Ray (1953) did not locate Oñate's letter. The summary written in Mexico City later in 1601 is reportedly based on Oñate's letter and also other reports carried with the couriers that left New Mexico on March 23, 1601. The summary was prepared for and sent to the Council of the Indies and the King, and colors Oñate's activity in New Mexico in the standard Mexico City view of the time as only rumors of progress with no real accomplishments except for the priest's claims of native conversion. Remember that the officials who supervised the writing of this summary are the same ones who conducted the fraudulent public assay that year. Hammond and Ray located the summary in the Archivo General de Indias (Patronato, legajo 22) in Spain. The original letter should contain the details on New Mexico mining that the summary said Oñate's letter contained but which were left out of the summary.

The fourth from the last paragraph of the summary was translated by Hammond and Rey as:

"The governor claims that at ten, fourteen, and twenty leagues from the pass of San Rafael,(3) where his camp is now, he has discovered many mines whose ores, on being assayed, were of high grade and contained much silver. Since he had but few people up to the present he has not allowed them to devote themselves to the exploitation of mines in order to prevent them from giving up the main objective of their undertaking through greed for silver.  But he has given orders [to Vicente de Zaldivar] to construct a mill for crushing and exploiting ores while he is inland [exploring great plains in 1601]."  (Hammond and Rey, p. 622).

As Vicente Zaldivar stated later in 1601 that Governor Oñate ordered him to develop the Cerrillos and San Pedro mines, and Oñate's letter of 3/22/1601 says that he had already given this order, we can narrow the time of the starting of the Cerrillos silver mines and construction of the mill to between March and July of 1601, and Anuncíation due to his discovery and development with his servants  (Tlascalans) of many other mines (Hammond and Rey, 1953, p. 815). Oñate apparently considered the Cerrillos and Tuerto deposits some of the most promising discovered and probably gave the order to develop them in 1599. By the summer of 1600, Zaldivar and his servants (Tlascalans) were mining in the Cerrillos Hills  (San Marcos) and in the Golden area (Anuncíation or Tuerto) 20 miles [32.2 kilometers] further south.  Zaldivar's mining results were good enough that other Spanish soldiers also started silver mines in the Cerrillos Hills. By July 1600, Zaldivar  was building small smelters and other machinery to refine the ore from the mines.

Vicente de Zaldivar was maese de campo of the colony. Juan de Oñate's nephew and his family had invested heavily in the colonization  of New Mexico. Zaldivar was petitioning for recognition of his service to the Crown and his interrogatory to the colonists were to collect evidence of his service. His question 15 was translated as follows,

"15. Whether they know that by order of the governor I went to explore the mines of San Mateo (sic., San Marcos) and Anuncíacion, because I had worked and examined many mines with my servants; that I have located many other mines which appear to be rich in silver and will result in much benefit and profit to the royal treasury and the welfare of this land."  (Hammond and Rey, 1953,  p. 815)

Hammond and Rey (1953, p. 883) only published the responses of two of the twelve individuals who gave formal responses to the interrogatories in July,1600, as they  felt the testimony of the others was essentially the same as the two they published.  The following are the two responses to Zaldivars question 15, on his role in New Mexico mining that they published. Alférez Leonis Treminos de Bañuelos, a life-long silver miner gave the following testimony at San Gabriel on July 29, 1600:

"Among the many discoveries of mines that the sargento mayor made are those of San Marcos and Anuncíacion, from which with the aid of his servants  (probably Tlascalan miners) and household, he obtained a quantity of silver, both by smelting and by the use of quick-silver. ... The sargento mayor has so stimulated us that this witness and others soldiers have been working the mines and taking out silver." (Hammond & Rey, 1953, p. 829).

Diego de Zubia's testimony, also taken on July 29, 1600, agrees with Treminos and specifies that Zaldivar discovered the mines of San Marcos and was the first to extract silver from them (Hammond & Rey, 1953, p. 821). Zubia does not mention any other location except San Marcos, thus confirming the Cerrillos Hills as a location of silver mining. Zubia was apparently not aware that Escalante or one of his 1581 companions discovered the Cerrillos silver veins.

Discontent among the colonists, as well as jealousy over Oñate's special  privileges, led as early as 1600 to investigations into his administration. In the spring of 1601, three soldiers and another man took reports from New Mexico to Mexico City. In Mexico City, a government attorney (factor), Don Francisco de Valverde, had been appointed by the Viceroy, the Count of Monterrey, to investigate the situation in New Mexico. The three soldiers apparently carried Vicente Zaldivar's 1600 petition, as Francisco de Valverde asked them essentially the same questions Zaldivar had asked in New Mexico a year earlier. Their responses to the question of "whether mines of gold, silver, and other metals had been found  since..." Juan de Oñate went there were as follows:

Marcelo de Espinosa said on July 28, 1601, "at the pueblo of San Marcos, six leagues from San Gabriel, silver lodes were found which, on being assayed by the smelting process, produced four ounces [0.1 kg]. He heard this told, and he also heard that there were other mines at the pueblo of El Tuerto which, it was said, were rich. The sargento mayor (Vicente de Zaldivar) stayed there to crush and smelt the ore, building machinery for this purpose. " ( Hammond and Rey, p. 641-642).

Captain Juan de Ortega testified on July 31, 1601, that he went with the relief  troops in December 1600 with the understanding that he did not have to stay in New Mexico unless he wanted to do so, and that he left three months later with the governor's permission.

In response to the question he said, "... he had heard the governor, the sargento mayor, and a captain say that there were mines, but that he had not heard of this from the other captains and soldiers. On the contrary, he heard some of them say that the minerals found were of no value and that there were no mines;..." (Hammond and Rey, 1953, p. 667)

Joseph Brondate on July 28, 1601 said, "at the pueblo of San Marcos, six leagues from the camp, there were mines with rich lodes. These ores, on being assayed, yielded four ounces. This witness saw it himself, and also that the sargento mayor was building a device to crush ore and extract metals, of which there were numerous reports " (Hammond & Rey, 1953, p. 630).

The weight or volume of ore that four ounces of silver assayed from is not stated by either Brondate or Espinosa. The standard volume of ore at that time was a quintal, or a fraction of a U.S. pound greater than 100 pounds [45.4 kg]. The ounce is the same as our ounce [28.3 grams] and a Mark was eight ounces [226.8 grams]. Four ounces [113.4 grams] per quintal equals 80 ounces per ton [2.3 kg per 0.9 tonne]. However, in 1600 that was not rich enough to be profitably smelted. The break-even point for smelting was from eight to ten ounces [226.8 to 283.5 grams] per quintal or 160 (Gonzalo Gomez de Cervantes, 1969, pp. 150-151)  to 200 ounces per ton [4.5 to 5.7 kg per 0.9 tonne]  (Probert, 1969, p. 96).  However, with the "Patio Process" of amalgamation, the break-even was around 20 ounces per ton [0.6 kg per 0.9 tonnes] or one ounce [28.3 grams] per quintal (Probert, 1969, p. 109-110). Thus, four ounces [113.4 grams] per quintal was good or bad ore depending on how it was going to be refined. Witnesses mentioned that amalgamation was being used, but that a Hacienda (Patio Process mill?) had still not been built in July 1601. The smelters built by Zaldivar were probably similar to the "Chimbo" furnaces described by Probert (1971), and the archaeological descriptions of furnace remains in Los Cerrillos (Warren, 1974) are compatible with that design.

Ginés de Herrera Horta was appointed in 1600 by the Viceroy as "chief  auditor and legal assessor" to Governor Oñate. The Viceroy probably sent Horta to New Mexico to gather information for him. Horta went there with the reinforcements that arrived on December 23, 1600. He did not give his reason for leaving three months later in March 1601, but his testimony indicates a bias against Oñate. Ginés de Herrera Horta was not a miner and only spent three months in New Mexico during the winter. He testified on July 30, 1601, that he,  "... had heard it said that at a pueblo named San Marcos there were silver lodes, but of very low grade. This witness saw a small piece of mineral which the sargento mayor showed to the soldiers. To all appearances it was very rich. He heard a friar, to whom the sargento mayor had showed it (the ore), say that it was fine if it were from that country. To this the sargento mayor made no reply." (Hammond & Rey, 1953, p.  653-654). Horta had not seen the mines and apparently based his comment on the San Marcos ore being of low grade solely due to Zaldivar's not responding to the friar's question.

Of the six witnesses whose 1600 and 1601 testimony Hammond and Rey (1953) published, the two engaged in mining in New Mexico give an optimistic opinion of mining, as did the other two long-time residents of New Mexico. The two individuals who had only spent three months in New Mexico, and did not claim any real knowledge of the area, gave pessimistic opinions of mining.

The attorney (factor), Don Francisco de Valverde, was still investigating the situation in New Mexico in 1602. However, the questions he asked in 1602 were not directly related to mining in New Mexico proper, but about what had been heard or seen of gold or silver on an expedition out onto the great plains. Thus the 1602  responses do not pertain to mining in what we consider New Mexico.

A large number of discouraged colonists fled New Mexico in 1600, including all but two of the friars. These individuals brought a variety of charges against Oñate for improper conduct, and tried to promote a negative picture of the prospects and conditions in New Mexico in order to justify their leaving without the governor's permission. As most of these individuals had signed up as soldiers for the entrada, they, in a legal sense, were deserters and subject to potential prosecution. One of the reasons for Vicente de Zaldivar's going to Mexico City in 1602 was to press for their arrest. Thus, there were a number of individuals around Mexico City trying to discredit Oñate and downplay all accomplishments in New Mexico, including mining.

Assays reported by Rossiter Raymond in the 1870's indicate that silver ore left on the dumps of the Santa Rosa and Ruelena mines averaged about 80 ounces of silver per ton [2.3 kg per 0.9 tonne] (4 ounces/quintal), [113.4 grams/quintal] well above the late 16th century break-even point by the Patio Process, but below break-even by smelting. The galena left at the Mina del  Tiro in the 1870's had considerably less silver. As the ore left on the mine dumps in the 1870s by the Spanish or latter miners would have been marginally profitable in the 1600s, it is reasonable to assume that the ore mined and refined in the 1600s was richer and profitable. If the assays of 200 ounces per ton [5.7 kg per  0.9 tonne] silver reported in the 1880s were correct, that would have been profitable by smelting in the 1600s. The record seems clear that the Cerrillos Hills contained  profitable silver ores and that these were being mined within three years of the European colonization of New Mexico.

The comments of the 1880's that the Spanish did not know how to smelt the silver-lead ores of the Cerrillos Hills are misleading taken out of their original context. These comments were originally made about the silver carbonate ores, which the first U.S. Period smelter at the railroad town of Cerrillos also failed  to smelt successfully in the 1880's. The silver-lead galena ores near the surface could be easily smelted as well as refined by mercury amalgamation using  the "Patio Process"  developed by Bartolomé de Medina in the 1550's which increased ten fold the recovery of silver from ore by mercury amalgamation (Probert, 1969).

Bartolomé de Medina's "Patio Process" was the greatest discovery in mineral  recovery or mining in the Western Hemisphere until the late 1800s. Without the Patio Process, silver mining would have died in the New World before New Mexico was colonized and very few mines would have been profitable anywhere. Some historians have said that it was the discovery or development of the great silver mines of Zacatecas and other places in Mexico that caused a loss of interest in exploring the far northern frontier (New Mexico) after Coronado's expedition. In fact, it was Bartolomé de Medina who made both the new and old silver mines extremely profitable all of a sudden in the late 1550s and shifted the New World's attention to silver mining from exploring for golden treasures that delayed the colonization of New Mexico.

If early Spanish mining in Los Cerrillos failed to be highly profitable, it may have been because the Patio Process was not used. Tremino's comment indicates that Zaldivar had not yet built a Patio Process mill at Cerrillos in July 1600, and he was recommending its construction. The patio process required water and salt, and the construction of tanks or a flat stone-floored patio for the ore to be mixed  on and aged in the sun. There are records of Oñate and others bringing mercury to New Mexico. The nearest good water supply would have been Alamo creek to the north of the Cerrillos Hills. The colonists had a good supply of salt at the Salinas (salt lakes) southeast of the Sandias, from which they shipped salt in the 1600's to the Patio Process mills of Parral. No remains of Patio Process mills have been located to date in the Cerrillos area.

Hammond and Rey (1953) translate the witnesses comments as "built machinery or devices to crush the ores," so we do not know at this point if the witness specified the type of machinery built. In later times (1700s - on), the arrastra (or tahona seen on the cover of this report) was the commonly used crushing machine. However, in the late 1500s the Spanish adapted and developed stamp mills of the German type seen in Agricola (1950), generally referred to as "ingenios" in Peru and "Molinos" in New Spain. If water powered stamp mills were built, they would have had to be built where there was enough slope in the stream to allow a ditch to raise the water high enough for a vertical water wheel to power the stamp mill, though some were run by animal power.

The Viceroy, the Count of Monterrey, after looking at the testimony collected by Valverde in 1601 and 1602, and other documents, wrote the King of Spain (Hammond and Rey, 1953, p. 906-) defending his reduction of Oñate's powers as well as concerning the abandonment of the colony by colonists in 1600 and conditions there. His comments are of a general nature, but indicate that he believed that there were good copper deposits and possibly silver deposits of some yet-undetermined quality in New Mexico.

"When silver or copper, which they say abound, are discovered,  we could introduce some form of coinage to circulate there. Some could be coined in that country and the value set low enough so as to leave a profit for the merchants who might bring and sell copper in bars. This seems impossible since the cost of transportation would be more than it is worth... I have not yet given up hope that we shall receive verification of what the governor still maintains, namely, that there is silver in some of the hills of the region where he is,...  Oñate now writes that he is going to make a more extensive search and that in the meantime he cannot be sure of any wealth, because he does not know whether there are minerals of sufficiently high grade. I am not discouraged, since we lack definite reports. If it should prove to be a silver country, no matter how low grade the ore may be, it would sustain the hope that by continued prospecting greater riches would be found in the hills and sierras. Even though it is not certain that there is silver, if means were found to establish copper coinage,  this would encourage and facilitate trade and aid in the support of the Spaniards there, even if the profits were not large. They have nothing to sell from which they can obtain cash, and poverty is everywhere. It therefore seems to me that these conditions, especially the lack of money, will discourage anyone from going there, or, if already settled, would discourage anyone from remaining there."  (Hammond and Rey, p. 913-914)

There is a document summarizing the situation in New Mexico prepared by or for the Viceroy in 1602, titled "Summary of the Five Discourses Presented by the Viceroy Concerning the Situation in the Territory that has been Pacified and Settled by the Adelantado Don Juan de Oñate in the Provinces of New Mexico, the New Explorations Made from there to the North, the help the Adelantado Seeks for this Purpose, and Other Matters". (Hammond and Rey, 1953, p. 899-). However, they did not print the portion on mining. Under Discourse III, they wrote, "The discourse continues with matters of government, cattle raising, climate of the country, and coining of copper coins from the metal found in that land. It speaks of silver  mines, which they assert are found, and of which possibility the viceroy has not lost hope. The last and necessary resort is to succor the settlers with some support from the royal treasury, and so forth." ( Hammond and Rey, 1953, p. 900)

The Viceroy Marquis of Montesclaros (1603-1607) wrote the King on March 31, 1605,  "Just lately letters have come from Don Juan de Oñate, together with samples of ores obtained from the mines that have been discovered. These I have assayed here (Mexico City), and thus far the richest ore produced one-eight part  copper, without any trace of silver"  (Hammond and Rey, p. 1001). Either the public assay referred to by the Viceroy in this 1605 letter is the one done by the preceding Viceroy in 1600, or else a second public assay was done after he took office in 1603 which also showed only copper. Don Alonzo Oñate (Governor  Oñate's brother) wrote the King of Spain on October 8, 1600, protesting a public assay done in Mexico City on ore sent from New Mexico. He wrote,

... after the governor (Juan Oñate) had sent rich silver  metals from the lands he had discovered (New Mexico)... all that turned up in the hands of the viceroy was a sort of copperish metal. This was assayed publicly, and as the assay produced only copper it served to cool the spirits of all those who were watching events. (Hammond and Rey, 1953, Part I, p. 581).

With the exception of Beerman (1979) and Simmons (1991), historians have largely ignored Oñate's recognition by the Spanish government as a mining expert in 1624. Considering that both Oñate and Vicente de Zaldivar were two of the most knowledgeable mining experts of their time, it should be self evident that they did not send copper ore to Mexico City as silver ore; someone along the way or in Mexico City deliberately switched the ore and/or faked the public assay in 1601. The only reason for staging a public assay had to have been to discredit Oñate's efforts and results in New Mexico. Past authors have tended to accept the 1601 public assay showing only copper at face value as evidence that there was no silver in New Mexico. There may have even been a second fake public assay between 1601 and 1605, as in that year the new Viceroy wrote the king that he had personally seen a public assay showing only copper. His often-referenced comment is thus invalid, and either he or his subordinates must have been involved in the subterfuge against Oñate.

A detailed study of the period (one is underway at UNM) would be required to know if the Viceroys were aware of the fraud or not, but fraud was involved. In view of the facts that Oñate and Zaldivar were very experienced silver miners, and had at least some very rich silver ore from the silver mines in the Cerrillos Hills before 1601, the assay had to have been fraudulent.

Though no discussion of the question by historians was located, there appears to have been a conspiracy to discredit the mineral discoveries in New Mexico as a means of discrediting Oñate's administration of the colony.


The Crown gave financial assistance and supplied soldiers as early as December  1600 to the Oñate Colony of New Mexico. It was not until a governor  appointed by the Viceroy was accepted by the colonists in 1610, that New Mexico  became just another provence of New Spain (Mexico). The debate over whether New  Mexico should be maintained or abandoned continued for decades but the Crown  accepted the idea that New Mexico would only continue if it subsidized the colony.  Cristóbal Oñate's administration of New Mexico (governor 1608-1610)  ended in 1610 with the arrival of the new governor subservient to the Viceroy.
note 5), and thus we only have records sent  out of the province before the revolt or written elsewhere. The only items located  in government reports written in Mexico City during this period were a comment by  the Viceroy in 1620 that the claimed existence of good mines in New Mexico had not  yet been verified, and a 1638 report claiming that although deposits of gold and  silver were well known in New Mexico, they had never been mined. Both documents,  as most other official correspondence of the period on New Mexico was slanted  toward convincing the King that he needed to continue or increase his subsidy of  New Mexico.

In 1620, the Viceroy wrote the king that the only town in New Mexico was Santa Fe, with only fifty residents (Spanish males?), and that the province was in danger  of being abandoned. "... although it is said that there are mines, this has not  been verified for sure, and the land is being maintained only in order not to  desert the baptized Indians."  (Hammond and Rey, 1953, Part II, p. 1140).

In 1638, in response to a royal cédula (Law or order)  requesting information on New Mexico, Father Juan de Prada collected information  from other priests who had been in New Mexico. He wrote the viceroy on conditions  in New Mexico for a response to the King's order for information. Father Prada  wrote that it was a very poor country and that Santa Fe was the only town with  about 50 houses (Spanish males?) with about 200 persons. That the colonists were  occupied with their encomienda services and defense of the  area and that there only income was the tribute paid them by the Pueblo Indians.  He also said, "Mines (ore deposits) of gold and silver are not lacking in that  country, as is evident from the experience that has been had with metals that have  been brought from there, but up to the present no mines have been worked there  because of the unfitness and poverty, not only of the Indians but also of the  Spaniards." (Hackett, 1937, p. 109). This  sounds very much like a paraphrasing of Salmeron's book which was published 8 years  earlier, which was probably available to Father Prada. One of Father Prada's  objectives was to defeat a proposal to end New Mexico's exemption from paying  tribute (taxes) to the Crown. He said the Christian Indians could not afford to  pay any tribute beyond the encomienda tribute they already paid to the colonists.

Statements by New Mexica

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