Guanajuato Revisited Part 7 of 17: The Panoramic Highway to the San Juan de Rayas Silver Mine

Ruins of Mina de Garrapata, viewed from La Panoramica. In order to get an overview of the old colonial city, Carole and I decided to drive the Panoramica (Panoramic Highway) that circles the hills surrounding Guanajuato. I soon discovered that many abandoned mines like the Garrapata line the route. The mine dates to the early 1700s and was so productive that its owners were ennobled by the Crown. Some of the even older 16th century mines still produce silver after almost 500 years. 

The Panoramica passes directly under the walls on the far side of Garrapata before taking a hairpin turn uphill to the turnout where I took this shot. I thought garrapata was a  romantic-sounding Spanish word until I learned that it stands for "tick"! In this posting, I will show you a bit of the view along the Panoramica and then we'll visit one of the most famous of Guanajuato's colonial-era mines, the Mina de San Juan de Rayas.

Map of La Panoramica and location of Mina de San Juan de Rayas. Both the Garrapata and San Juan de Rayas mines can be found directly alongside the Panoramica, on opposite sides of a deep arroyo where the road takes a hairpin turn at its northern tip. The highway, which was completed in the 1970s, provides a way to look down on the city from the four corners of the compass. For an interactive Google map of the Guanajuato area, click here.

La Panoramica

Guanajuato is surrounded by steep hills and rugged mountains. The city is built up the sides of the hills and along the ridge tops. This provides many stunning views all around the city. Turnouts along the way provide accessible spots for viewing and photos. The Panoramica is not nearly as long as I thought it would be. However, if you decide to take it, allow a couple of hours, at least, for stops along the way to visit some of the fascinating old colonial churches and abandoned mines. 

Another view from the Panoramica. Although well-paved, access to the two-lane road is mostly unrestricted, with lots of cars and pedestrians in the built-up areas. Drive cautiously. Steep flights of stairs rise up or descend from the Panoramica, connecting one neighborhood to another. After I saw several women carrying heavy loads of groceries up those long sets of steps, I didn't envy them their views quite so much.

Templo de San Cayetano de la Confesor, at the Mina de Valenciana. The Templo was built between 1775 and 1788 by the mine's owner, Antonio de Obregón y Alcocer. The architects, Andrés de la Riva and Jorge Archundia, chose the Churrigueresque style and used pink cantera stone for much of the work. The use of this Baroque style was unusual for the late 18th century, as Neo-Classic was popular by then.

The Valenciana mine was named for Don Diego Valenciana, who discovered silver in the general area in 1557. The mine was not particularly productive for the next 200 years and it sometimes stood idle. Then, in 1760, Antonio Alcocer made his first investment in the Valenciana after he got a loan from Pedro Luciano Otero, a merchant who had also been investing in the San Juan de Rayas mine. The two men poured money into the Valenciana, buying new equipment, introducing new processes and hiring more workers. 

The Valenciana's peak occurred between 1768 and 1804, when it produced an astonishing 60% of the world's silver. It suffered some production interruptions after that. For example, in 1817 the Independence War insurgent Javier Mina burned the mine's machinery to keep silver out of the hands of his royalist opponents. The following centuries also brought numerous ownership changes. Still, in 2022, after almost 500 years, the mine produced 2.15 million ounces of silver, worth $54,223,000 (USD).

Mina de San Juan de Rayas

Google satellite view of Mina de San Juan de Rayas. The mine stands at the end of a short plateau surrounded on three sides by steep walls. The Panoramica forms a "V" as it passes through. Former administrative offices cross between the two wings of the V near the center. 

Between the Panoramica and where high walls drop off to the steep slopes below, four circular structures stand near the V's bottom. A roofless structure stands to the left of the Panoramica near several purple-flowered trees. Ore carts, old pumps, and winches are scattered about.

 

The Rayas mine from below its vertical exterior walls. The church on the upper left is the 17th century Templo de la Merced de Mellado, built by the wealthy, mine-owning Bustos y Moyo family. We will visit it in the next couple of posts of this series.

The San Juan de Rayas was the first mine in Guanajuato. It got its name from a muleteer named Juan Rayas. In 1550, he noticed silver ore while driving his animals along a trail. What he had discovered was Guanajuato's veta madre ("mother vein") of high-grade silver, gold, and gold quartz. Between 1550 and 1750, most of Guanajuato's mines were small, primitive, and focused on high-grade ore located near the surface. A few miners became wealthy but most returns were marginal.

During its first 150 years, the Rayas mine was one of those marginally profitable operations. Then, near the end of the 17th century, a Spaniard named Pedro Sardaneta leased it. He struggled to make a profit and lost his lease for a time, but his descendants regained control and became extremely wealthy from investing in the mine. His grandson, Vicente Manuel Sardaneta y Legaspi, was so successful that, in 1774, King Charles III made him the 1st Marqués de San Juan de Rayas.

Old photo of the mine and its workers. This was probably taken in the later 19th or early 20th centuries. The small heaps in front of the crowd of workers are crushed rocks ready for sorting into silver-bearing ore and waste. The roofed structure in the center may lead to the mine's entrance, which I never saw because it was probably blocked up when the mine closed. 

However, I was able to find a description of the mine's interior, as well as the sort of jobs the workers' did. The mine reaches a depth of  420m (1378ft). There are four shafts, beginning with the "General". Two vertical shafts are called the "Garrapata" and "Santa Rosa de Lima", while an inclined shaft is called the "Kurtz". There are also galleries, rooms, and space for four malacates de sangre (water drainage pumps), as well as a tunnel that connects with the General shaft.

Rayas mine workers during the late 19th or early 20th centuries. Most were young men. Their harsh working conditions meant life expectancy was only about 36 years. During the 2nd half of the 18th century, 42% were indigenous. Some of these were free workers but others worked under the repartimiento system of forced labor. 22% were free mulattos (indigenous/African). Another 1.4% were mulatto slaves. 19% were mestizos (indigenous/Spanish). 11% were Spanish and 3% were "other".  

A big 18th century mine like the Rayas needed thousands of workers for all the largely-unmechanized tasks. The biggest group was split up into several hundred small crews, usually 3 men plus a foreman. One kind of crew included a borer who drilled the rock, a barratero who pried the ore loose, and a man with a pick to assist. Sometimes a boy called a pepe helped by holding up a light. Another crew of three men called tentataros carried ore sacks to the surface. Buscones cleared dirt and rubble, an unskilled and risky job which sometimes caused landslides.

Outside the mine's entrance, workers called breakers smashed the rocks carried up by the tentateros. The valuable ore was then separated from waste by pepenadores (women and children). Other workers included dispatchers who filled leather sacks with water to fight flooding and herders who tended mules that turned winches to haul the sacks to the surface. At the surface, men called drawers then dumped the water. Blacksmiths and carpenters tended to the winches and other machinery. 

Rayas' administrative offices. At the top of the mine's hierarchy was an Administrator who had wide authority to govern the mine. Many of these men parlayed their positions into ownership shares. Just below an administrator was a manager for each of the various mine shafts. The Shaft Managers supervised the Senior Miners who, in turn, supervised the Foremen of the various crews. 

Rayadores paid out wages after ensuring that workers had made a scratch by their names before they left the mine after turning in their tequio (quota of ore).  Partidores measured out the partido. This was ore collected by a worker beyond the tequio, which belonged to him as a form of profit-sharing. The partido was viewed by workers not only as a source of additional pay but as giving them status as part-owners of the mine.

The partido was established after the native population crashed by 90% between about 1550-1650. The major labor shortages that resulted allowed free workers to migrate from mine to mine to seek the best deals. The partido was the owners' strategy to ensure stable work forces. When the labor pool began to expand again in the 18th century, some owners of large mines like Rayas tried to eliminate the partido. This angered workers, who saw it as a pay cut but also as a status reduction. It was one cause of the miners' revolts of 1766-67. 

One of the four circular structures seen in the Google satellite photo. This is the one on the far right. The wall above is about 1m (3ft) thick and 4m (12ft) high, while the interior diameter is about 30m (90ft). All four structures are of identical size, but only half of the one on the far left remains. My best guess is that their function was storage of the ore in preparation for shipment to a hacienda de beneficio for final refining into ingots. They must have been built after 1906 because a photo from that date does not show them. 

Haciendas de beneficio were usually separate from the mines and often located near arroyos or streams because the refining process required abundant water. Vicente Manuel de Sardaneta y Legaspi  was the owner of the Rayas mine during much of the 18th century. He also owned the nearby hacienda de beneficio called Hacienda del Cochero (see Part 5), along with other mines and refining facilities. Sardaneta supplied all of these with food and livestock from other haciendas he had acquired.

To view other former haciendas de beneficio, see Casa de Espiritus Alegres. It is now a bed-and-breakfast located along an arroyo in Marfil,  just south of Guanajuato. Carole and I stayed there during our 2008 visit. Many other haciendas de beneficio that once operated in Marfil have now been converted to private homes or boutique hotels. Another example is Hacienda Jalisco, located in the silver mining pueblo of San Sebastian del Oeste, not far from Puerto Vallarta. 

 

This circular structure looks like a Greco-Roman amphitheater. The ground surfaces within the circular walls of the other structures are level, but this one has been reconstructed as a site for some sort of performances. 

The transformation of rock from deep inside a mountain into a silver ingot required numerous steps, as described above. Extracting silver from the ore involved a number of difficult problems that caused many mines to fail. Until well into the 18th century, miners used the fuego ("fire") process to heat the ore until the silver melted out. However, fuego only worked well with high-grade ore, generally found near the surface. When this was exhausted many mines shut down. 

Those with access to capital, like the owners of Rayas, needed to dig deeper. However, lower-level veins often contained only lower-grade ore. Even worse, the deeper the shaft, the more the mines flooded. At this point, mines producing low-grade ore and lacking the capital to pay for the machinery and workers to deal with the flooding became uneconomical. They either shut down or sold out. Mining was always a risky "boom or bust" affair.

Mill stone used to crush ore. A long axle ran through the hole in the center. At the other end of the axle was a mule that endlessly trudged around in a circle, rolling the stone over chunks of rock to crush them. Once they were reduced to a size that could be sorted and sacked, other mules hauled the ore to a hacienda de beneficio. 

In 1554 a Spaniard named Bartolome de Medina invented the mercury amalgamation process to solve the problem of effectively refining the lower-grade ore. First, the ore was further crushed by an arrastra (stamp mill) to the consistency of sand. This was then formed into piles resembling huge, flat pancakes 0.30-.61m  (1-2ft) thick. Next, mercury, salt-water brine, and copper sulfate were mixed into the piles, either by the feet of bare-legged workers or horses. 

Because all this occurred in large open areas, it was nicknamed the "patio process". After about eight weeks of mixing and soaking in the sun, the mercury amalgamated with the silver. This was then placed in a hooded oven where the heat evaporated the mercury, leaving nearly pure silver. The final step was to melt it into ingots for transport by mule trains to Mexico City and shipment to Spain. Over time, the use of the patio process grew, allowing many mines to reopen. 

Ore carts on rails were a 19th century innovaction. These replaced the tentateros carrying heavy ore sacks as they climbed up rickety wood ladders during the previous 300 years. Just  beyond the ore carts is the sheer wall that drops down to the steep mountain slopes below.

The effectiveness of the amalgamation process was improved even further in 1768. That year, a Guanajuato doctor named Manuel Dominguez de la Fuente began collaborating with the Rayas mine's owner, Vicente Sardaneta to test a new amalgamation method. The experiment succeeded in increasing silver yields and did so using much shorter processing times. 

The Rayas mine's silver production began to boom the very next year, along with that of other mines,. In 1769, the value of Guanajuato's overall silver production reached 732,000 pesos, then jumped to more than 1,021,000 in 1771. In 1776, it shot up to 1,456,510 pesos, almost double the value from only seven years before. However, the patio process had one very serious Achilles Heel: reliance on mercury.

One of the more modern pumps used to prevent floods. This one was probably installed during in the late 19th or early 20th century period when the dictator Porfirio Diaz was encouraging foreign investment in Mexican mines. Over the course of less than a century, water removal methods moved from mule-power, to steam, to electricity. The solution, or at least diminution of this critical problem allowed many mines to reopen and revitalized the whole mining industry.

The mercury problem grew out of Nueva España's status as a Spanish colony. As a financial measure and a means of control, the Crown maintained a monopoly over the production and distribution of mercury to the mining community. The price and particularly the availability of mercury were serious concerns to every owner. The cost of mercury or its absence could cripple or even completely shut down production. Worse yet, it was not just the Crown that could do this.

Virtually as soon as Spanish galleons full of silver and gold began sailing the oceans in the 16th century, pirates had begun to attack them. Some of the captured ships carried the vital mercury supplies. In addition, between the invention of the patio process and the end of the Napoleonic Wars in 1815, Spain was in almost constant conflict with other European powers. The English, French and Dutch had strong fleets and an equally strong interest in shutting off Spain's silver supply. 

The pump's name plate indicates its American origin. The plate reads "Ingersoll-Rand, New York, Imperial Type 10". The end of colonial rule in 1821 gave the new Mexican nation free access to mercury. In addition, the population increase during the last quarter of the 18th century meant more available workers. This could have resulted in dramatic new profitability for the Rayas mine. However, by the early 19th century, its useable ore was exhausted and the mine shut down.

Although they lost the income from the Rayas, the Sardaneta family continued to exercise great power in Guanajuato through their wealth and position. Upon Vicente's death in 1787, his son José Maria de Sardaneta y Lorente became the 2nd (and last) Marqués de San Juan de Rayas. Despite his noble title, José became active in the struggle for independence. He was imprisoned and exiled several times by the royalists but survived. José retired from politics after independence, dying in 1835 at the age of 48.

Despite gaining free access to mercury and a more stable labor pool, the first 2/3 of the 19th century were not good for mining. From the start of the Independence War of 1810 until the end of the French Occupation in 1867, Mexico endured an almost constant series of wars, invasions, revolts, and insurgencies. During this time, the mining industry suffered severely and many mines were destroyed or went out of business. 

This initially appeared to me to be a chapel. Although the narrow interior and window shape made it look like a religious building, it was actually used to house steam-driven water pumps. La Concordia mining company, owner of the mine in 1887, installed them to stop flooding. Later, the pumps were converted to electricity. The double winch seen above may be the one mentioned in a report that described such equipment being used to haul cages full of workers up and down the shafts.  

The last quarter of the 19th century and the first ten years of the 20th were known as the Porfiriato. Conditions in the mining industry dramatically improved, at least for the owners, if not necessarily for the workers. During those 35 years, the dictator Porfirio Diaz established political stability and actively sought international investments to modernize the nation's infrastructure. Much of this investment came from British and American sources and went into railroads, ports, and particularly the mining industry. 

However, in 1910 the Porfiriato ended with the Revolution, followed by the Cristero War of 1926-29. Various revolts and chaos lasted into the 1930s. Foreign investment evaporated and mining in Guanajuato and much of the rest of Mexico again fell into ruin. Stability finally came back in 1934, with the election of Lázaro Cárdenas, Mexico's version of Franklin Roosevelt. Mining in Guanajuato has never recovered to its former levels, but it still continues and tourism and other industries have helped fill the gap.

This completes Part 7 of my Guanajuato Revisited series. I hope you have enjoyed it. If so, please leave any thoughts or questions in the Comments section below or email me directly. If you leave a question in the Comments, please remember to include your email address so that I can reply in a timely manner.

Hasta luego, Jim