The Ruhr region is probably the best-known industrial region in Germany. It was shaped by heavy industry and coal mining in the 19th and 20th centuries. It is named after the Ruhr River, which runs along its southern edge. The area belongs to the Westphalian Lowland Plain, the Lower Rhine Plain and the Rhenish Slate Mountains. There is a deposit of Upper Carboniferous coal-bearing strata here. The coal seams lie along the Ruhr at the surface and dip towards the north. At the latitude of the Lippe river, they lie at a depth of 600 to 800 metres. Their thickness is usually between 1 m and 3 m.
The coal was formed in the Devonian and Carboniferous periods, when the area was a large swampy depression filled with tropical rainforests. With the onset of Variscan mountain building 400 to 300 million years ago, the Rhenish Slate Mountains were uplifted and the northern foreland lowered. The forests were periodically overlain by thick sandy sediments. With increasing pressure from the overlying strata and increasing temperature from the earth's interior, coalification occurred, slowly converting the plant material into hard coal. This resulted in hundreds of coal-bearing layers, of which only about 70-80 seams are worth mining, In addition, in the course of mountain building, ore solutions rose along tectonic fault lines and some ore deposits were formed.
The discovery of the burning stones is attributed to a shepherd boy who built a fire. He noticed that the stones lying in the fireplace began to glow and gave off heat all night. Since the 13th century, coal was mined in small quantities for personal use, From the 17th century at least, coal was dug on a larger scale on the south bank of the Ruhr. Seams of coal came to the surface here and were easy to mine in open-cast mines. By 1755 there were almost 200 mines in the Ruhr region. In the 18th century industrialisation began with individual ironworks, in 1758 the St Anthony ironworks in Oberhausen-Osterfeld, in 1782 the Gutehoffnungs ironworks in Oberhausen-Sterkrade and in 1791 the Neu-Essen ironworks in Oberhausen-Lirich. At that time, the ores were still smelted with charcoal.
Through coking, coal could be used to smelt iron in blast furnaces. This meant that people were no longer dependent on limited quantities of charcoal and production exploded, This is generally regarded as the beginning of the industrial revolution. In areas like the Ruhr, where rich coal reserves and iron deposits met, the process accelerated. By 1850 there were almost 300 collieries, plus coking plants and iron and steelworks for producing pig iron and steel. The collieries migrated northwards and became deeper and deeper, following the coal. The area was opened up with the development of railways and canals. Population numbers rose sharply, due to immigration from other parts of Germany, an above-average birth rate, but also immigration from other countries. Workers' settlements, so-called colliery colonies, were built and the Ruhr coal district became the largest industrial conurbation in Europe.
Mining in many European coal and iron mines came into crisis in the 1970s due to cheaper raw materials on the world market. Jobs declined sharply in the Ruhrpott as well, and many collieries closed. Low-level mining was still maintained until the 2010s through subsidies, but was then discontinued for reasons of climate protection. In the meantime, there is not a single working colliery left. The most interesting collieries have been listed and can be used as museums or event venues. However, most of them have been demolished.