Excerpt of 'From the Erzgebirge To Potosi'

Retired Canadian mining geologist Sean Daly offers a profile of seminal metallurgist Georgius Agricola
Excerpt of 'From the Erzgebirge To Potosi' Excerpt of 'From the Erzgebirge To Potosi' Excerpt of 'From the Erzgebirge To Potosi' Excerpt of 'From the Erzgebirge To Potosi' Excerpt of 'From the Erzgebirge To Potosi'

Georgius Agricola, physician and early mining geologist and mining engineer

Sean Daly

By way of a brief preamble, I am the author of From the Erzgebirge to Potosi. I am a retired Canadian mining geologist and my book is a brief history of the history of mining and geology in the last 500 years in the world, mostly in Europe and the Americas.

It discusses the close relationship between mining and geology and society such as during the Renaissance and the Industrial Revolution and modern times and including some labour struggles.

My book also reviews De Re Metallica, written by Georgius Agricola and published in 1555 about everything to do with underground silver mining at that time, in the Erzgebirge Mountains in Germany.

The link with the Mining Magazine is that its founder, Herbert Hoover translated De Re Metallica together with his wife from Latin to English. As for my book, more information is available about it on my website.

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( Excerpt ) The Life and work of Georgius Agricola

In 1527, Agricola was made the town physician at Joachimsthal (now Jachymov) in the now Czech Republic. The little city in Bohemia is located on the eastern slope of the Erzgebirge (or Ore Mountains), in the middle of the most prolific metal mining district of Central Europe. Joachimsthal was a thriving mining camp, founded but 11 years before Agricola's arrival. Among other books he wrote on the subject, over a period of 25 years he wrote and researched his main work, De Re Metallica or "Concerning everything to do with metals".

The main advances of Agricola were in the fields of Geology, Mineralogy, Surveying, Ore Processing and Mining Engineering. This most important contribution Agricola made was based on, in his own words, "those things which we see with our eyes and understand by means of our senses are more clearly to be demonstrated than if learned by means of reasoning".

In other words in practice and in word, he promoted the results of observation versus inductive speculation. This was the main characteristic of the development of the scientific method in the Renaissance, This tenet was also abundantly exemplified by William 'Strata' Smith, son of a blacksmith, who had but a grade school education in England but by hard work and careful observation ended up making the first geological map of all of England and most of Scotland in the 1800's.

A modern-day example of this approach to geology and mining engineering was a Honduran 'maestro' in charge of all shaft sinking in the El Mochito Mine (underground) in Honduras in the 1970's who learned his trade totally from experience and could even read and understand blueprints and was in charge of all shaft sinking and with only a grade school education.

Basically, Agricola, 'Strata' Smith and this Honduras shaft sinking working foreman all used the method of dialectical materialism even though they probably had never heard of it but in learning well from material experience and from its dialectical aspects (the development and resolution of contradictions) they became experts in their respective related fields.

Georgius Agricola was born in 1494 in Glachau in Saxony, Germany and died in 1555. Agricola entered the University of Leipsic at the age of 20 and there gained the degree of Bachelor of Arts. He become a lecturer at this University. In 1524 he went to Italy for the further study of Philosophy, Medicine and the Natural Sciences. He remained in Italy from 1524 to 1526 for almost three years.

In 1526 Agricola returned to Zwickau, and in 1527 he was chosen town physician at Joachimsthal. Thence to Freiberg is but 50 miles. Freiberg is where the renowned early geologist Abraham Gottlob Werner taught his geology courses. Most of the mining towns mentioned in De Re Metallica were centred at Freiberg. Joachimsthal was a booming mining camp, recently founded.

According to Agricola's own statement, he spent all the time not required for his medical duties in visiting the mines and smelters, in reading up in the Greek and Latin authors all references to mining, and in association with the most learned among the mining folk.

In 1530 and 1533, he published Bermannus (a dialogue on metallurgy) and De Mensuris et Ponderibus (about Greek and Roman weights and measures). At about this time he began De Re Metallica, not to be published for 25 years, which gave him time to gather a wealth of information in all aspects of underground milling and make this a definitive work for about 180 years.

Agricola resigned his position at Joachimsthal in about 1530, and devoted the next two to three years to travel and study amongst the mines. About 1533, he became city physician at Chemnitz, in Saxony, and here he resided until his death in 1555.

In 1546, at the age of 52, began Agricola's activity in public life, for in that year he was elected a Burgher of Chemnitz; and in the same year Duke Maurice appointed him Burgomaster-an office which he held for four terms.

To deduce Georgius Agricola's character we need not search beyond the discovery of his steadfast adherence to the religion of his fathers (Catholicism) amid the bitter storm of Protestantism around him, and need but to remember at the same time that for 25 years he was entrusted with elective positions of an increasingly important character in the same community. No man could have held the respect of his countrymen unless he were devoid of bigotry and possessed of the highest sense of integrity, justice, humanity and patriotism. He was also a friend of Erasmus the Great Humanist,

Publications

In 1544, began the publication of the series of books to which Agricola owes his fame, The first volume com-prised five works and was finally issued in 1546; it was subsequently considerably revised, and re-issued in 1558. These works were; De Ortu et Causis Subterraneorum, in five books, the first work on physical geology; De Natura Eorum quae Effluunt e Terra, in two books, on subterranean waters and gases; De Natura Fossilium, in 10 books, the first systematic mineralogy; De Veteribus et Novis Metallis, in 2 books, devoted largely to the history of metals and topographical mineralogy, among others. Agricola completed De Re Metallica in 1550, but it did not appear until after his death in 1555. Agricola is known as the "father of mineralogy'',

Legacy

Agricola's famous book, De Re Metallica became the authority on all things related to underground mining for at least 180 years, all gained from close observation and consultation with the local miners, mining officials and technical personnel mostly in the Erzgebirge Mountains.

(From Chapter 5)

De Re Metallica-A Summary of Agricola's Ideas

Groundwater and Pumping Methods

An area of underground mining essential to its success that Agricola spoke of, was groundwater and pumping methods, of which there were several in his day. The fact that for several years the rich silver of parts of Saxony could not be mined until a new drainage adit at Rammelsberg was completed (in the 16th century) shows the importance of de-watering, just like at modern underground mines like El Mochito, Honduras where mining couldn't take place without de-watering.

Agricola says, "Water is either hoisted or pumped up out of shafts". Further on he says: "Water is drawn up also by chains of dippers, or by suction pumps, or by 'rag and chain' pumps. When there is but a small quantity it is either brought up in buckets or drawn up by chains of dippers or suction pumps, and when there is much water it is drawn up in hide bags or rag and chain pumps", The method of chains of dippers uses a series of small buckets which hold the water. For a human-powered such device, a person at the surface turns a large axle which meshes with a large gear which is connected to the chain of dippers drum, which then turns to pull up the dippers full of water. The excellent drawing of such a device makes it easy to describe, showing how art can illuminate for example, the science of pumping water.

Further, in describing another machine, "The third machine, which far excels the two just described, is made when a running stream can be diverted to a mine; the impetus of the stream striking the paddles revolves a water wheel in place of the wheel turned by treading" (or turning the axle as in the above method).

Details of Piston Pumps

Further on, actual pumps are described by Agricola thus, "Enough then of the first set of pumps" (dippers). I will now explain the other, that is the pump which draws, by means of pistons, water which has been raised by suction". Agricola describes at least seven types of piston pumps. The seventh one is described as follows, "The seventh kind of pump, invented 10 years ago, which is the most ingenious, durable and useful of all, can be made without much expense. It is composed of several pumps which do not, like those last described, go down into the shaft together, but of which one is below the other (staged-my comment), for if there are three, as is generally the case, the lower one lifts the water of the sump and pours it into the first tank; the second pump lifts again from that tank to a second tank, and the third pump lifts it into the drain of the tunnel.

 iston umps illustration from e e etallica Piston Pumps illustration from De Re Metallica

 

A wheel 15 feet high raises the piston rods of all these pumps at the same time and causes them to drop together. The wheel is made to revolve by paddles, turned by the force of a stream which has been diverted to the mountain". These then are some of the pumping systems, either water driven or human-powered, used in the 16th century to ensure the mines were kept dry enough to produce ore safely.

The pumping of copious amounts of groundwater also was done at the modern underground El Mochito Mine in Honduras, from deep within the mine, and was staged so that there would be pump stations every few levels so that the hydraulic head would not be too great to lift it all at once to the surface so this technique stood on the shoulders of the Erzgebirge miners.

Also, there, since there was so much groundwater in the limestone, if the pumps shut down for only a minute or two, the shaft would start to flood, so a very large auxiliary generator was standing by at all times on the surface in case the power grid power went down, a problem the Erzgebirge miners did not have though their mines were most likely a lot shallower than the relatively deep El Mochito Mine which was about 2400 feet deep in 1973.

Water wheels or water mills have a 2,000-year history. They have been used for many things including grinding grains to pumping water to generating small amounts of electricity. Water wheels powered much of the medieval industry in the 10th and 16th century. As seen in the illustration to the left from De Re Metallica, even as far back as the 16th century, water wheels were used to power underground mine pumps. What is considered the largest water wheel in the world at 72 ½  ft in diameter —known as the Laxey Wheel- was constructed near the town of Laxey on the Isle of Man in 1854, to power pumps to dewater the nearby Laxey underground mine.

This mine was over 300 fathoms (a term usually used for the ocean where 1 fathom equals 6 feet) deep, and produced 1/5 of British output of zinc in the 1870s as well as significant lead and copper. 600 miners were employed by the mine at its' peak. As well as valuable minerals found at depth, there were prodigious amounts of groundwater which had to be removed to facilitate mining.

 igure 34 he axey heel at the axey ine in the sle of an Figure 34: The Laxey Wheel at the Laxey Mine in the Isle of Man

 

If coal had been available on the island, a coal-powered steam engine would have been used to power the pumps. Unfortunately, there was no coal on the island and importing it would have been prohibitively expensive. A self-taught engineer, Robert Casement set about to find a solution to the problem. Fortunately, water power was readily available on the island. Casement had water from nearby streams diverted into channels and then into a cistern. From the cistern, the water was piped via a bridge to the top of the water wheel into buckets on the wheel's circumference and the weight of the water in the buckets then moved the wheel. The wheel moved at three revolutions per minute, This movement powered a long mechanism crankshaft that in turn powered the water pumps. The result was de-watering of the mine up to the approximately 1,500 feet depth of the main shaft and at a rate of 250 gallons/minute. In this way, the miners could continue to produce ore and it ensured the mine made a profit.