The illustrated guide to sixteenth-century mining

Posted: December 20, 2024

Imagine for a moment that you’re a prince in sixteenth-century Europe and you want to open a mine. In centuries past, you would have had to travel to a mining hotspot, attempt to recruit some of its experts, and hope that they had enough combined knowledge to get your mine up and running. This being the sixteenth century, however, you have no such worries: the finer points of prospecting, extracting, and smelting are only as far away as your nearest bookseller.

Written by the German scholar Georgius Agricola and published in 1556, De re metallica is arguably the mining industry’s foundational text. It standardized the technical language of mining—albeit in Latin— and according to Sidney Pollard, a scholar of industrialization, “remained in use as a textbook for 180 years, being replaced by a more up-to-date work only in 1738.”^[1]

The work can be read today in English thanks to an unlikely duo: it was translated by an American mining engineer called Herbert Hoover and his wife Lou, who would later become President and First Lady of the United States.

If you’re curious about De re metallica but don’t quite have the Hoovers’ commitment, today is your lucky day. Here’s the five-step guide to sixteenth-century mining, complete with illustrations from the original manuscript that we’ve digitally restored and colored specially for this piece. 

 Ready? Let’s mine like it’s 1599!

Step 1: Prospect

In the first half of the 1500s, population growth and technological innovations combined to drive a central European mining boom. But while the extraction of metals like copper and silver increased by as much as 500% between 1460 and 1530,^[2] locating fresh deposits remained more of an art than a science.

The pseudoscientific practice of dowsing, which involves holding a Y-shaped stick and being guided by its movements, remained widespread. “There are many great contentions between miners concerning the forked twig,” writes Agricola, “for some say that it is of the greatest use in discovering veins, and others deny it.”

Agricola was firmly in the latter camp, arguing that any deposit located with a divination rod was down to chance. It was far better, he advised, to look for clues in the state of vegetation above ground than to rely on a “wizard” with an “enchanted twig.”^[3]

Step 2: Dig

After a vein was located and the area above ground had been delimited, the next step was to build the above-ground infrastructure that would house the equipment, men and ore from the mine. Then an initial shaft was sunk, from which tunnels were dug horizontally into the rock. As the tunnels spread, further shafts were sunk to connect with different parts of the underground network^.[4]

Agricola specifies that completed shafts were usually 13–14 fathoms deep (about 25 meters), but there are records of many far deeper mines. The huge Röhrerbüchel complex in the Austrian alps had shafts plummeting almost 900 meters into the rock, with the deepest reaching 144 meters below sea-level and providing access to 17 levels of tunnels.^[5]

Step 3: Extract

When mining at the depths described by Agricola, two issues were—and indeed remain—particularly persistent.

The first was flooding. Agricola outlines in detail differing designs of pumps that were used to draw out water from the mine. The largest of these contraptions (below left) was a machine of impressive sophistication.

At the bottom of the shaft, a network of gutters directed water into a central reservoir. Above ground, a waterwheel “thirty-six feet in diameter” (11 meters) was used to draw up vast buckets of water from the underground reservoir. Lever-operated water gates controlled the speed and direction of the waterwheel’s rotation, thus allowing for the precise movement of buckets up and down the shaft.

The second perennial problem facing mines of the period was ventilation. In the deep shafts and narrow tunnels of the day, miners employed a system of bellows to draw out the “heavy vapors” and refresh the “stagnant air.”

The woodcut above shows three different ways of powering a set of bellows. At the bottom is a man-powered approach that, according to Agricola, is powerful enough to keep a tunnel “as great as 1,200 feet long” safely ventilated. If it were not for these powerful bellows, Agricola notes, miners would have had to replenish the air inside mines by digging many more shafts and tunnels.^[6]

Step 4: Assay

Once deposits had been extracted from the mine, their composition and quality had to be tested. The actual process of assaying, according to Agricola, “differs from smelting only by the small amount of material used,” but no sensible mine owner should skip it:

By smelting a small quantity, they learn whether the smelting of a large quantity will compensate them for their expenditure; hence, if they are not particular to employ assays, they may […] sometimes smelt the metal from the ore with a loss or sometimes without any profit; for they can assay the ore at a very small expense, and smelt it only at a great expense.^[7]

Step 5: Smelt

Smelting was arguably the most technical part of early-modern mining—and was the area in which Germans were the most advanced. They were especially adept at grinding and sifting ore, which greatly improved the efficiency and yield of the smelting process.^[8] Another German innovation outlined by Agricola is the addition of bellows to furnaces. This allowed for bigger furnaces at hotter temperatures.

The woodcut below depicts the smelting of iron into steel. Mined ore is melted in the furnace, with the iron gradually separated from impurities. Over multiple hours-long cycles, bars of the metal are extracted from the furnace, cooled in running water and inspected for purity.

Bonus step: Sell—or try to

Of course, the final and most important step was to sell—at a profit—smelted bars of metal to blacksmiths, forges, mints and jewelers. Alas, for all their technological sophistication, sixteenth-century German miners would find this last step increasingly difficult.

Historian Sidney Pollard explains: “On the one hand, the ore supplies began to give out, at least as far as existing technologies could reach them at acceptable cost; on the other, a stream of more cheaply acquired gold and silver from the Americas began to flood the European market.”^[9]

It is a cruel irony that the publication of Agricola’s masterpiece coincided with the start of German mining’s decline—although perhaps Saxon miners would have taken some comfort in the success of De re metallica, for in its pages their astonishing ingenuity remained current for decades, even if the mines they worked collapsed into ruin.

Illustrations adapted from high-resolution scans from the Wellcome Collection and low-resolution images on Project Gutenberg. Original woodcuts by the artist Blasius Weffring.

References

^{[1] Marginal Europe: The Contribution of Marginal Lands since the Middle Ages, Sidney Pollard, p187.
[2] “The Openness of Knowledge,” Technology and Culture, Vol. 32, No. 2, Part 1 (Apr, 1991) Pamela O. Long, p324.
[3] De re metallica, Book II, Georgius Agricola, trans. Herbert and Lou Hoover, via Project Gutenberg.
[4] De re metallica, Book V.
[5]Marginal Europe: The Contribution of Marginal Lands since the Middle Ages, Sidney Pollard, p185.
[6] De re metallica, Book VI.
[7] De re metallica, Book VII.
[8] Power, Knowledge, and Expertise in Elizabethan England, Eric H. Ash, p28.
[9] Marginal Europe: The Contribution of Marginal Lands since the Middle Ages, Sidney Pollard, p198.}