As our program comes to its midpoint, we spent the day at Kutná Hora, a historically significant town ninety minutes outside Prague situated right in the middle of the country. From the late 13th century through the 16th century, the town was the seat of Bohemia, and a bulk of Europe’s, silver production. Until sources from South America and the New World outpaced it, Kutná Hora was responsible for around a third of European silver at its peak, and as such became the second most important city in the Czech crownlands after Prague. Development of the mines led to the establishment of the Royal Mint in the town, pressing over six thousand Prague groschen a day and paving the way for Kutná Hora’s position as the financial capital of the region.
Between our tours of various churches and other sites in the town, we were given the opportunity to explore a fraction of the old silver mines underneath the sloping hillsides. After a quick brief of the pulley and venting technology, we donned our coats and helmets and descended 33 meters into the first layer of the mines. The floor was slick with drippage from overhead and several offshoot paths were flooded in crystal clear water. Sections of the mine wall appeared melted due to the centuries of erosion, taking on a smooth, cream-colored texture.
As we made our way through the underground channel the walls and ceiling tightened in on us. About midway through we all hunched to squeeze through the barely four-and-a-half foot tall passage, our arms pinned against us as the walls shrank to maybe two feet apart. We stopped at a wider opening in the middle to talk about the conditions of the mine as they would have been for the miners sin antiquity. Tall wooden logs and stacks were erected in the space to mimic the support structures of the time, and there was a moment we all dimmed our headlamps to plunge into the complete, lightless dark that the more unfortunate miners would sometimes find themselves in.
The medieval miners were equipped with two tools only: a small hammer and a chisel, with which they cared away at the rock face. With only small animal-fat lamps to guide them, they spent six to seven hours plunged in near total darkness, at the deepest points 500 meters underground. Though wind channels and other implements were installed to aid the process, ventilation was poor, and flooding from regional rainfall and the crossing of unknown, closed shafts made the process doubly dangerous. Cave-ins and other accidents would leave many crippled and the humidity within would rot the wooden support beams. Many miners would begin their careers around age 20. Few would make it beyond 40.
Nevertheless, the techniques used to extract such a vital resource were innovative and rather genius for their time. Ventilation, for example, would be implemented via tall, vertical venting shafts crowned with wooden sails to catch and redirect the wind below. Many different styles of cranks, some by hand and others drawn be draft animals, were used to raise anything from a few kilos to whole miners to tons of silver and other material out from the mines. To better access and extract the silver deposits, fires were lit in the deeper passages to superheat the rockface. When cooled, and the smoke vented, the new rock would be brittle and easier to break with the simple hand tools available. After being ported to the surface, the silver would be melted down alongside lead to create an alloy easily filtered through a kiln for later refining into 0.925 silver, a standard consistent to today. Once the final alloys were formed, workers at the mint would press the hot silver on marked dies to make the final Prague groschen coins that would supply the whole of Bohemia.
It was fascinating to dive head-first not only into the conditions the miners experienced (granted, an immeasurably lighter load) but to get a firsthand look at the industrial infrastructure required to pull off such a complex operation. Even in what we now consider more primitive times reliant on hand tools and manual labor, extensive industrial and architectural feats were still accomplished. This sentiment was not unique to the mines, but to the whole of Kutná Hora, which was especially prevalent in the many churches we visited throughout the day. St. Barbara, the patron saint of miners, held an impressive gothic church just above the mines we travelled in, equipped with tall, stained glass windows and flying buttresses to support the upper walls. Like St. Vitus Cathedral on the Pražský Hrad grounds, the church was only fully complete in 1906 after centuries of expansions and renovations. The original design from the 13th century still shines through, and much of the church was built during the operation of the mines with some of the very same technologies and tools. Both sites are exemplars of what great works may be accomplished when ambition and moneyed interests converge, no matter the sophistication or technological limitations of the period.
Swanson School of Engineering 