Urban Grids #2: Subterranean vertical

Related to a previous post on the city of Guanajuato’s unique urban grid structure, the mined landscape surrounding Guanajuato has another unique grid generated by existing landscape features.  The steep topography surrounding the city has been mined for hundreds of years, more or less continuously since the time of the Spanish conquistadors.

(Historical mine drawings from the Guanajuato museum)

Most of the tunnels were excavated with pre-industrial age tools and techniques, chiseling through stone and carrying out the wasterock in wheelbarrows.  Over time the exploitation of the landscape (and the native enslaved population that did 99% of the labor) has left an extant and sometimes still used circulatory infrastructure analogous in structure to ant colonies.

Below is a stitched together photo of a hand drawn sectional map of the hills at the periphery of Guanajuato.  I encountered this amazing drawing tucked away under plastic near the  unassuming entrance to one of the mines (the original map is scaled at 1:2000 and was approx. 4’ long).  The section covers a large extent of territory; showing the contour line of the hills (and how they have been altered) and the series of mines and subterranean passages below the ground’s surface (click on image for larger view).

Sectional map of the Guanajuato surrounding landscape (original is 4′ long).

Partial detail from above image

Moving in closer shows the intricacy of the network of extraction tunnels.  The form of the network was completely pragmatic in intention as the tunnels followed the geologic veins of silver.  The red vertical lines are wide vertical shafts with mechanized elevators that were added to the mines much later, allowing miners to descend thousands of feet below the surface much faster (before the elevators that they had to climb and descend ladders).

Inverting the values of the drawing make them a little easier to read and hint at the absolute blackness of space that would be encountered  there.

The Valenciana mine is one of the oldest (begun in 1558) and most productive mine in the region.  The mine is still in operation and the central shaft now descends over 1,800′ below the surface

Detail of the Valenciana maze of tunnels.  How were the spaces and tunnels maps and measured? How did the author figure this out in such contoured detail?  From what information?

Figure and ground intricately interlaced

Rayas mine central shaft

The photo above gives a sense of scale of the mine.  This view is staring down the central shaft of the Rayas mine.  The seemlingly tiny elevator cart in the top right portion of the photo can carry about 5 miners.

These subterranean grids are like small cities in and of themselves, or isolated villages from some fictional scenario.  They read like a passage out of Italio Calvino’s Invisible Cities….a city of hell where workers spent a large part of their lives working and dying within them.

Memorial and prayer shrine in the rayas mine

Developed over generations, these mining remnants are amazing testaments to the labor that went into their incidental production…a by product infrastructure that created the wealth and impetus for the above ground city.  What will become of this extraction infrastructure as the silver and other valuable metals run out and the tunnels become completely obsolete?  Will they become habitat for something else, human or otherwise?

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