A series of exhibitions deals with the various different technologies used in the mining industry to extract, transport and utilize the coveted mineral resources. The main focus is on underground mining, but surface mining, borehole mining and marine mining are also covered.
Before extraction can begin, deep deposits must first be made accessible. In lowlands this generally involves mineshafts. The underground mine workings have to be lined or supported and adequately ventilated. Water has to be pumped out, and the mineral must be extracted and transported out of the mine. Since it is not possible to work in complete darkness, miners also need lamps.
In addition to the actual mining engineering, separate sections of the exhibition are concerned with the processing and refining of raw materials, e.g. by briquetting or coking.
Das Grubengeleucht gehört zu den elementarsten Hilfsmitteln des Bergmanns in der Dunkelheit unter Tage. Erst das Licht ermöglicht überhaupt eine gezielte bergmännische Arbeit. Allein die vielen besonderen Namen wie Frosch, Gießer, Schelle, Granate, Linsenlampe, Kuckuck, Blende u.a. vermitteln einen Eindruck von der Variationsbreite des Grubengeleuchts. In ur- und frühgeschichtlicher Zeit zündete man dazu brennbare Materialien wie Kienspäne an oder benutzte Öllämpchen aus Ton o.ä. In vielen Bergbauregionen haben sich typische Lampenformen entwickelt.
Bei den besonderen Gegebenheiten im Steinkohlenbergbau stellte die offene Flamme eine große Gefahr dar, führte sie doch zur Entzündung von Grubengasansammlungen (Methan) und damit zur gefürchteten Schlagwetterexplosion. Diese Gefahr nahm mit dem Vordringen in größere Teufen während der Industrialisierung zu. In England brachte 1815 die Davy-Lampe als Öl-Sicherheitslampe einen Durchbruch in Richtung eines Explosionsschutzes. Diese Technik fand ihren Weg auf den Kontinent und wurde in unzähligen Patenten als Benzin-Sicherheitslampe, auch Wetterlampe genannt, in Deutschland weiterentwickelt. Letztlich wurde aber die Sicherheitslampe nach wiederholten Schlagwetterexplosionen in Steinkohlenbergwerken in der ersten Hälfte des 20. Jahrhunderts durch elektrisches Geleucht ersetzt.
Die Ausstellung zeigt die Entwicklung des Grubengeleuchts und die außerordentlich große Variationsbreite an Typen und Bauformen.
Extraction is the collective term for all tasks connected to the mining of usable deposits. The mineral resources/raw materials can be solid, liquid or gas. The extraction methods are correspondingly diverse: ores and salt are usually extracted by blasting, whereas coal is extracted by cutting machines such as double-drum shearer loaders or coal ploughs.
The large machines used in surface mining of soft rock overburden, especially the bucket-wheel excavators used in lignite mining, are particularly impressive. Numerous models illustrate how these work, and give an idea of their gigantic dimensions. No less impressive is the use of offshore drilling platforms for the extraction of oil and natural gas.
Another section of the exhibition gives a preview of the extraction of raw materials from the seabed, a procedure that is likely to become more widespread in future. The design of this part of the exhibition is based on Auguste Piccard’s bathyscaphe (deep-sea submersible).
Shaft construction and hoisting
The shaft, generally a vertical mine structure, connects the surface installations of a mine with the underground workings. Numerous models in the exhibition illustrate the development of shaft construction and hoisting.
Loose and water-bearing rock create the greatest challenges for shaft engineering. Special mention should be made here of the technique of freezing shaft construction, a complex and laborious process in which the water-bearing rock is frozen to depths of several hundred metres before and during the sinking of the shaft, to make it stable and water-impermeable. In the past miners used ladders to get up and down the shafts, an adventurous, strenuous and dangerous undertaking. Progress came with the double-acting man engine, and then with rope haulage by means of a pit cage. This is still in general use today and can be experienced in the visitor mine.
True-to-scale functional models help to explain how shaft hoisting with pit cages and buckets worked. An extensive collection of functional models of steam engines used to power shaft hoisting machinery is particularly popular.
Drainage and ventilation
Drainage or dewatering includes all measures taken to keep the mine workings free of water. The most elegant solution is natural drainage, where water flowing into the mine is drained off through sloping main level adits, the entrances of which are as low down as possible. As mines become deeper, such natural drainage is no longer possible, and energy must be used to remove the water. Models illustrate the use of slaves as water bearers in the Roman mining industry, and the subsequent development of various pump installations, culminating in modern electric submersible pumps.
Ventilation serves to supply the mine workings with oxygenated air, and to remove noxious gases and oxygen-depleted air. In coal mining there is an additional problem: the supply of fresh air must be designed in such a way that no explosive firedamp mixtures are created as methane escapes. Ventilation can be natural or artificial. Artificial ventilation is largely independent of the natural pressure and wind conditions. In the past the energy needed to drive ventilation systems came from humans, horses or hydro power. Today powerful mine fans are used.
This exhibition is concerned with the refining of coal into coke. Coke is needed for the production of raw iron in the blast furnace process. In the coking furnace, high temperatures and the exclusion of air turn bituminous coal into the new, refined product, coke, as well as generating various by-products. These include benzene, tar and ammoniac, which were initially regarded as waste products, as they could not be utilized.
The exhibition shows the development of coke oven technology since the beginning of the 18th century. One particularly interesting exhibit is a hinged model of an Otto Hofmann oven, an invention which marked the beginnings of the extraction of by-products in the coking industry. Further exhibits relate to the workplace of the coke-maker: here the main items on display are typical implements used by the operating crews of the former Hansa coking plant in Dortmund. The exhibition also shows films about the coking industry from both historical and contemporary perspectives.
Mine support systems
Mine support systems ensure that the cavities excavated by miners underground remain safe and accessible. Until just a few decades ago, this was almost always done with wood or stone; today, however, the main materials used are steel and concrete. The history of the development of roadway support systems reveals an extraordinary range of variations. This is not only the case for wooden supports, but also for mixed support systems and steel supports, of which numerous different types are displayed as models.
The original exhibits displayed here show the development from 2000-year-old wooden supports from a copper mine on Cyprus to the first modern steel hydraulic roof supports.
Extracting machines, hoists, haulage and heavy machinery
This section of the collection is located in the machine hall on the basement floor of the museum, and can be reached via a staircase from gallery 2. This functions as a walk-in open-access repository, and contains numerous original machines which cannot be displayed in the exhibition galleries on the ground floor and upper floor due to their size and weight.
The exhibits here show the development of coal-cutting machines from the disc shearer to the double-drum shearer loader. The collection of hoists includes the oldest steam hoist of the Ruhr district, as well as a steam-driven flat-rope double-reel hoist, and an electric drum hoist. There is also an impressive collection of different mine cars and locomotives, powered by compressed air, benzene, diesel or electric engines. Further exhibits housed in the machine hall include drilling jumbos, road heading machines, various roof supports and transport systems, and the largest lump of coal ever extracted from an underground mine.
Processing and refining of raw materials
Processing and refining serve to turn the raw materials extracted from the mine into saleable products. In general, the material brought to the surface is a mixture of different mineral components which has to be separated by type, e.g. coal and rock.
Sorting uses the different properties of the mineral components, e.g. their density or wettability, to separate them. Sorting is usually preceded by crushing processes and grading by particle size, since each of the various sorting techniques only functions within a more or less narrow range of particle sizes. Along with numerous representative individual exhibits, the exhibition also contains the entire annealing ore processing plant from the Waldhausen mine in the Lahn district.
Refining is the subsequent processing of the raw material. In the case of briquetting, small coal is agglomerated in a special briquette press. In the past the briquettes formed in this way were mainly used as domestic fuel to fire ovens. The exhibition shows different types of briquette presses, and a collection of decorative briquettes produced for various special occasions.