The Silver Mines of Hostotipaquillo Part 10 of 10: Ex-Hacienda Santo Tomas (the silver refining area)

The patio where the crushed silver ore was mixed with mercury. The large metal door just to the right of center is the entrance to the zaguan (entrance hall) which leads to the casa grande's courtyard. (See Parts 7, 8, and 9). The structure to the right of the casa grande was used for storage of mercury and the equipment used for processing the ore, and possibly to safeguard the finished silver ingots. The fountain in the middle of the patio was a decorative touch that was probably added after the hacienda switched its focus from silver refining to distilling tequila. 

This is the final posting on ex-Hacienda Santo Tomás and it also finishes my ten-part series on the silver mines of Hostotipaquillo. In this part, I'll show you the patio where the silver was separated from the ore by amalgamating it with mercury. I'll also take you into the area where furnaces and an oven were used in the final stage of the refining process. Behind the ovens are the stables for work and riding horses. 

Another view of the storage building, taken from the atrium of the capilla (chapel). The main gate is on the right side of the photo, under the red tiles. On our third trip to ex-Hacienda Santo Tomás, we were finally able to gain access to the interior of the property when we found the main gate open. On the theory that asking for forgiveness is easier than asking for permission, we decided to go inside to look for someone who might allow us to explore. The families who own these old places are nearly always proud to show them off. True to form, the hacendado's son was in residence and he invited us in.

The patio, looking toward its northeast corner. My friend Jim B is the figure photographing the fountain. The storage building is in the upper left, with the main gate just to its right. Barely visible behind the palm trees to the right of the gate is the capilla shown in Part 7. In Part 8, I showed a couple of carriages parked in the zaguan. These would have entered through the main gate and off-loaded their passengers at the entrance of the zaguan, which is out of sight to the left.

Once the silver ore was delivered by pack mules from the mines, it was crushed into a thick powder by the grinders connected to the water wheel seen in Part 9. It was brought to this patio and spread out on the cobblestones to form a large, flat, circular pancake. Using the  hooves of horses, the ore was then mixed with mercury, copper sulfate, and a salt water brine. After several weeks of mixing, the silver amalgamated with the mercury and could be recovered for the next step. For a complete description of the amalgamation process and the history of its development, click here.

The enclosure containing the furnaces, oven, and the stable is accessed here. This doorway is located on the east side of the courtyard. The capilla is out of sight to the left. The figure in the doorway is Tom, another of our Hacienda Hunters. He rarely misses an opportunity to go along on one of these adventures. Tom is also a talented photographer whose photos I have occasionally used to illustrate this blog. 

Ex-Hacienda Santo Tomás has a maze-like layout. Although I got to explore some of the areas inside the casco wall which surrounds the main structures, I did not have time to view and photograph some of it. Hopefully, some time in the future, I'll be able to return for another look.

Looking back out into the patio through the entrance of the ore oven complex. The fountain and the door to the casa grande's zaguan can be seen across the patio. Notice the steel gate on the doorway of the oven complex and the thickness of its walls. Everything about this area, and the hacienda as a whole, says "security".

The oven complex

Two furnaces created the heat for burning off the mercury. At the far end of this structure is a metal door that is standing open. The outside of the door has a temperature gage. Based on descriptions I have read, I can make an educated guess about how these ore furnaces functioned. Fires in the furnaces created heat, which was then funneled to the large room where the silver/mercury amalgamation was placed. 

The heat caused the mercury to evaporate into fumes. These fumes condensed on specially placed surfaces. This allowed the collection and reuse of the mercury, which was expensive and could sometimes be difficult to obtain.  

The temperature gage is mounted at the center of the large metal door. The "C" with the degree symbol indicates that the gage uses the celsius scale. The highest temperature is 110C which translates to 230F. Although the boiling point for mercury is 376.73C, it is a volatile metal that can even evaporate at room temperature in some situations. Mercury's evaporation temperature can be lowered by applying heat.

During the Virreinato (Viceroyalty or colonial period), the Spanish Crown maintained a monopoly on mercury. Because it was an essential part of the refining process, this raised considerable revenue for the Crown. However, it also created a means for controlling the colonial mining industry and the men who were growing rich from it. 

A major problem grew out of Spain's involvement in various wars during much of the 16th, 17th, and early 18th centuries. Its ports were sometimes blockaded and ships carrying mercury to Nueva España (Mexico) were often captured. All this caused periodic supply shortages and sometimes even led to mine shutdowns and widespread economic disruption. 

The remains of various pieces of machinery are scattered near the ovens. The geared wheels of this one were driven by the large, smooth wheel which was once turned by a strap. It is not clear exactly what role this machine played in the refining process. 

Each of the two furnaces has a small arched opening on its back side The purpose of the openings may have been to draw air into the furnace to increase the heat. Notice the small sign in the upper right which says "PROD. FINAL", meaning "Final Product". This was where the finished ingots would have been collected after the molten silver was poured into molds to form them.

A small office stands between two of the oven complex's buildings. This was probably the office of the man who was responsible for the refining process. This manager would have been a key figure who reported to the hacienda's mayor domo (administrator). Education and technical training would have been necessary for anyone who occupied this position.

The stables

Behind the ovens are stables for the hacienda's work and riding horses. There are two wings, shaped like a capital "L", with five stalls in each. The lifespan of the work horses that were used to mix the mercury into the ore was probably fairly short. The chemical is very toxic to animals as well as humans. The horses trudged around a post centered in the pancake of ore spread out in the patio. 

This process occurred over a period of weeks, during which the horses' legs were in direct contact with the mercury. They would have also breathed it in through their lungs. When work horses were not available, human workers were sometimes used in the same way, 

A friendly horse comes over to say "hi!" The carriage or riding horses kept for the use of the hacendado and his family faired much better than the work horses (or the low level workers, for that matter). Fine riding horses were especially prized on Mexico's haciendas. They not only provided excellent transportation but they were a way of displaying status. Pride in the ownership of horses and in horsemanship is still found all over Mexico, but particularly in the state of Jalisco, which is the heart of Old Mexico.

Ths completes Part 10 of my Silver Mines of Hostotipaquillo series, as well as completing the series itself. I hope you have enjoyed it and have perhaps learned something about the role of silver in Nueva España and the early Republic. If you would like to leave your thoughts or any questions, please do so in the Comments section below or email me directly. If you leave a question, please include your email address so that I may respond in a timely fashion.

Hasta luego, Jim