Extraction and processing of stone
The extraction and processing of stone includes process engineering and production engineering components.
process technology
The handling of quarry stone , field stone and aggregate belongs to the field of process engineering . When mining natural stone, a distinction is made between loose, semi-solid and solid rock . Solid rock is extracted in the quarry , often with the help of blasting . Soft rock is extracted in gravel mining or as reading stone . Most of the products are in bulk .
Until modern times, natural stone was extracted manually using stone splitting tools such as crowbars and splitting wedges , for example wooden wedges that swell with water. If the stone had no natural fissures, holes had to be drilled for the wedges, which is now done with a hammer drill . The historical profession of stone mason was preoccupied with this work. There is not always a sharp difference to the stonemason : The stonecutters also made individual parts such as paving stones .
Stone sawing has been widespread since around 1900 and allows a high yield. Tools for this are the helicoid saw , the cutting machine , the wire saw , the stone circular saw and also the water jet cutting machine . Rough blocks are cut into sections with gang saws .
manufacturing engineering
While stones were processed with other stones in the early history of production technology, today they are processed on the one hand on industrial production lines by machine tools with diamond-tipped tools, on the other hand still with hand tools and historical techniques. There is work stone processing from the prehistoric to the present day. Using the tool traces, work processes can be reconstructed and historical classifications can be made.
By means of primary molding , stone can be made from the raw materials sand or gravel with the appropriate binding agents ( artificial stone ). They are processed like natural stone, for example with stone cutting machines.
The turning is for marble, alabaster, soapstone used sandstone and various gemstones. It was not only important for works of art and tableware, but also for the manufacture of columns as building materials and rollers for the paper industry.
The stone surface allows conclusions to be drawn about the manufacturing techniques of historical objects. A distinction is made between rough processing with a relief of one millimeter to a few centimeters and fine processing , which combines grinding and polishing .
Historical stone processing
Prehistoric time
Along with wood , natural stone is the oldest building material in human history. The natural stone caves, such. As the Lascaux cave , the cave of Altamira and Chauvet cave deliver us impressive cave images that were either painted or carved with hard stone in stone walls.
The first stone surface processing took place in the Stone Age as part of stone tool manufacture. In the Stone Age z. B. made of flint core devices such as hand axes and teeing devices. The rocks were first shaped by cutting off, then the working edges were retouched. In later times, surface processing was added by grinding. Mainly Neolithic stone axes were cut. This work could take up to 24 hours, depending on the size of the ax blade. The polished ornate axes were considered a status symbol. Another form of surface treatment is pecking. Millstones were roughened in this way, and rock ax blades shaped by controlled blows.
antiquity
Ancient Egypt
For the rough work on soft and hard stone, the Egyptian stonemasons used shaped stone handpieces made of dolerite or granodiorite that were guided with both hands . These tools were used by the Egyptians to extract rough blocks of granite , diorite or gabbro and to produce stone surfaces that remained rough or were further processed. This tool use is documented by finds of these tools and tool remains.
Between 1500 and 600 BCE , wooden knobs and chisels made of copper and later of bronze were used for the finer processing of soft stone, and only then iron tools. The stone surfaces were smoothed with polishing stones (pumice) and emery material such as quartz sand . Iron chisels, iron stone splitting tools and wedges made of iron were not used in Egypt until Roman times .
The less valuable stone surfaces were rough and only sculptures and valuable stones such as sarcophagi or articles of daily use were removed with emery material, e.g. B. polished quartz sands.
Ancient Greece
The Greek stonemasons used bronze and iron pointed chisels, possibly two- pointed hammers . They used tooth irons , and according to archaeological finds it is also assumed that the tooth surfaces were used . If parts with radial shapes like profiles were to be smoothed, the Greeks partially used chisels . Also round iron that had a round edge rather than a straight edge. From the middle of the 5th century there are traces of stone drills. Metal rasps were mainly used in places where paint was to be applied later. The sculptures were the chisels manufactured and "lightened" by means of this technique work on the surface, which gave the sculptures of the famous velvet character. At that time, however, the rough surface was necessary so that colors could adhere, because the Greek sculptures were painted in color.
In ancient Greece, stone reliefs were masterfully incorporated into space and wall design in buildings, which today are still exemplary for the art of stone carving , such as the gigantomachy frieze of the Pergamon Altar . The stone surfaces were rough, and sculptures were polished from the 3rd century onwards.
Ancient Rome
The Romans essentially adopted the stone-working technique of the Greeks. Pieces of stone were removed from Greek buildings on a large scale and transported to Rome. There was a difference in Roman stone processing from the Greek: the closer they got to the end surface of the marble , the more they worked with the pointed chisel at a shallow angle and used chisels for smoothing to finish polishing. In this way you avoided a matt surface with the light bumps in the marble. Finally, the valuable decorative and architectural sculptures could be optimally sanded and polished; and she shimmered transparently. Architectural decorations and stone sculptures were polished; the less valuable stone surfaces remained rough.
middle Ages
The studies of the Ulm minster master builder Karl Friedrich in 1932 resulted in a standard work on historical stone surfaces on buildings in Central Europe from the 11th to the 18th century.
Since 2016 there is a new book by Peter Völkle about work planning and stone processing in the Middle Ages , which supplements or replaces Friedrich.
In connection with historical sources, stonemason tools and stonemason's markings , stone surface treatment represents an important part of today's building research .
Pre-Romanesque and Romanesque
Flattened stone surfaces were created in the Romanesque period. These were made with the smooth surface , a stone ax with two cutting edges. The smooth surface leaves groove-shaped depressions. In this case, groove next to groove was knocked out at a millimeter distance. In the later course of time these grooves were flattened diagonally as the stone surface was leveled and later crisscrossed. This resulted in different patterns (see table below) that enable today's building research to assign a time. Later they used a tooth surface that has serrated cutting edges. The tooth surface leaves rows of punctiform indentations next to each other. Both the smooth and the tooth surface is a tool that is guided with both hands.
Gothic
The Gothic stonemasons converted the surface into a stone ax with a working width of approx. Three centimeters, which they mastered with virtuosity and which was called the pill. They also used the tooth iron for the first time in Germany. The typical stonemasonry tool of the Gothic, the chisel iron probably imported from France, was not used until the middle of the 15th century. The blade at that time was about 5–6 cm wide. For the first time, scratched stone surfaces are created. The cuts of these tools were arranged at a 60 ° angle to the outer edge.
Renaissance
During the Renaissance, the hinge was made wider and the stone surfaces were made with the so-called wide hinge, which was more than 12 cm to 20 cm wide. The cut arrangement was at right angles to the outer edge. In addition, during the Renaissance, stone surfaces were hand-ground to produce smooth stone surfaces. The stonemasons invented a new tool for working sandstone, the crown . This tool creates punctiform depressions in the millimeter range in the stone surface.
Baroque, historicism and classicism
In these epochs we find a changing processing, which is expressed in sharpened, chiseled to ground stone surfaces. The cuts, which were carried out by hand, were mostly stilted on sawn surfaces. The hard rock tool, the stick hammer, was invented because more and more hard rock was being worked on.
With the inventions of machine stone processing with stone saws and stone grinding machines , it became possible on a large scale to produce ground and polished stone surfaces.
Overview: 11th to 18th centuries
The following overview shows the development of the historical stone surfaces with hand-held stonemason tools of the Ulm cathedral builder Karl Friederich from the 11th to the 18th century.
| Machining | Tool | surface | Edge impact | time |
|---|---|---|---|---|
| Sharpening | Bicorn or pointed iron | - | very narrow, approx. 1.5 cm | Until the middle of the 11th century |
| Patterned sharpening | Bicorn or pointed iron | - | very narrow, approx. 1.5 cm | Until the middle of the 11th century |
| Processing | Smooth surface | no desired order of the blows yet | very small | Until the beginning of the 12th century |
| Flattening | Flat surface or punch | intentional order of the blows | very small | Until the middle of the 12th century |
| Muster | Smooth surface | Alsatian herringbone pattern is a special form | medium wide, approx. 2.5 cm | First half of the 12th century |
| Surface area | Smooth surface | gross loading processing | medium wide | If the teeth were flattened after being flattened, this ends at the end of the 12th century. If there was no flattening, there was a gradual transition to smooth pilling. |
| Tooth flattening | Tooth surface | gross loading processing | very wide, approx. 4.5 cm | Late 12th century to late 13th century |
| Tooth pilling | narrow tooth surface (tooth pill) | fine About processing | very small | Until the middle of the 14th century |
| Smooth pilling | narrow flat surface (pill) | - | very small | Until the middle of the 15th century |
| Scratching | Scharriereisen , narrow | - | narrow | From the middle of the 15th century to the 17th century |
| Broad band | Sharpening iron, wide | Chopping blows very roughly and vertically | medium wide | Since the middle of the 17th century |
| Alternating processing | sharpened, sharpened, sanded | mostly stilted | 16th Century |
Non-European cultures
The non-European peoples have also achieved great technical, craftsmanship and seemingly superhuman achievements in the processing of natural stone surfaces when they put seamless walls and walls together from huge stones, for example the Incas in Cusco and the Khmer culture in Angkor Wat . Stones weighing up to 160 tons were precisely processed and transported. These services raise questions that cannot be conclusively answered. This led to spectacular claims. The achievements of the Incas in Machu Picchu and Cusco are explained by border scientists with extraterrestrial forces or the use of "stone softeners". In the meantime, some questions about stone building technology at that time could be traced back to geological and simple physical laws. The processing techniques and the use of tools in the non-European countries have so far been little researched.
See also
literature
- Holger Reichenbächer: Cutting mineral materials with geometrically determined cutting edges , Univ. Press, Kassel 2010. ISBN 978-3-89958-836-1
Individual evidence
- ↑ Manufacture of stone axes
- ↑ Rosemarie and Dietrich Klemm: The stones of the pharaohs . State Collection of Egyptian Art, Munich 1981, p. 34 ff.
- ↑ Bettina Schmitz: The stones of the pharaohs . Pelizaeus Museum, Hildesheim 1985, p. 20.
- ^ Carl Blümel : Greek sculptors at work. 2nd Edition. Walter de Gruyter, Berlin 1941, p. 56.
- ^ Carl Blümel : Greek sculptors at work. 2nd Edition. Walter de Gruyter, Berlin 1941, p. 64 f.
- ^ Karl Friedrich: The development of stone from the 11th to the 18th century . Filser, Augsburg 1932, pp. 36-37.
- ^ Peter Völkle: Work planning and stone processing in the Middle Ages . Ebner Verlag, Ulm 2016, ISBN 978-3-87188-258-6 .
- ^ Karl Friederich : Stone processing in its development from the 11th to the 18th century . Filser, Augsburg 1932, p. 66 ff.
- ^ Karl Friederich: Stone processing in its development from the 11th to the 18th century . Filser, Augsburg 1932, pp. 36-37.
- ↑ In recent research it is assumed that historical stone-working traces such as "crowned" or "flattened" are a consciously produced "ornament" and not the result of a technical process. See in particular Hans-Peter Autenrieth: About the fine relief in Romanesque architecture. In: Franz J. Much (Hrsg.): Architecture of the Middle Ages in Europe. Hans Erich Kubach on his 75th birthday. Stuttgarter Gesellschaft für Kunst und Denkmalpflege, Stuttgart 1988, ISBN 3-926168-00-5 , pp. 27–70. Since the human work process of stone processing both design and contains, as well as technical aspects, the assessment by Friederich subdivision appears Be processing and over continued processing durable, even more comprehensive.
- ↑ Joseph Davidovits , A. Bonett, AM Mariotte: The disaggregation of stone materials with organic acids from plant extracts, an ancient and universal technique. In: A. Aspinall, SE Warren (Ed.): Proceedings of the 22nd Symposium on Archaeometry. Held at the University of Bradford, Bradford, UK, 30th March-3rd April 1982. Schools of Physics and Archaeological Sciences University of Bradford, Bradford, W. Yorks 1983, ISBN 0-9508482-0-4 , pp. 205-212. The experimental "proof" provided there (scratching with a plastic spatula on limestone, with and without the addition of acid) appears more than dubious.
- ↑ C. Singewald: Natural stone buildings of the Inca: Secret and techniques - a question of faith . ( Memento of February 4, 2007 in the Internet Archive ) 2004 (PDF; 1.6 MB).