De prehistorische vuursteenmijnen van Rijckholt - St. Geertruid

Useful Information

Location:	Near Rijckholt, 600 m walk towards St. Geertruid. 6 km southeast of Maastricht. Meet at the church of Ryckholt, at the Kaffee Riekelt. (50.7946099, 5.7446789)
Open:	JUN Wed 19, Sat 14. JUL to AUG Wed, Thu 19, Sat, Sun 14. SEP Wed 19, Sat 14. Online booking rwequired. [2023]
Fee:	Adults EUR 8, Children (0-11) EUR 4. Groups (-15): Base EUR 65, Adults EUR 9, Children (4-14) EUR 4.50. [2023]
Classification:	Stone Age Flint Mine Room and Pillar Mining Oldest Mines
Light:	Incandescent Electric Light System
Dimension:	T=8-10 °C.
Guided tours:	L=300 m.
Photography:
Accessibility:
Bibliography:	(1998): de Prehistorische Vuursteenmijnen van Ryckholt - St.Geertruid, Nederlandse Geologische Vereniging, Afd. Limburg. Werkgroep Prehistorische vuursteenmijnbouw. ISBN: 90-801523-4-X
Address:	Stichting Ir. D.C. van Schaik, Postbus 2235, 6201 HA Maastricht, Tel: +31-43-3672584 E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

6200 BP	begin of mining.
4650 BP	end of mining.
1881	first flint-working sites discovered in the south of the Netherlands by the Belgian archaeologist Marcel De Puydt.
1903	exploration by the Liège Professor J. Hamal-Nandrin (*1868-✝1958).
1914	first shaft and mining gallery discovered.
1923-1925	excavations by the Dutch archaeologists Prof. Dr. van Giffen and Dr. v.d. Sleen.
1929-1932	Dominican monks made extensive excavations and found more than 100 stag horn hoes, black clay shards, a polished stag horn hammer and around 1200 flint hoes (picks).
1964	more shafts discovered by Prof. Dr. H.T. Waterbolk from the Biological Archeological Institute of the Groningen University.
1964-1972	tunnel of 150 m length constructed into the prehistorical flint mines by members of the Netherlands Geological Association.
1979	discoveries exhibited in a new museum, tunnel opened to the public.
MAY-2003	new electric light.
2004	eight additional AMS-14C datings were carried out, revealing a much longer timespan.
2017	managed by De Stichting ir. D.C. van Schaik.
2021-2022	mine and visitor center closed for renovation.clo

Geology

The Meuse valley was cut into the soft Cretaceous chalk by the river Meuse. Changes is the amount of water and thus the speed of downcut created three terraces. Rijckholt is located on the middle terrace. All three terraces were covered by sediments which where deposited by the river. On top of those gravels, sand and clay, a layer of loess was deposited, fine rock dust which was created by the glaciers of the last cold age by grinding the rock and blows across the glaciers by wind and deposited in basins. The loess here is a result of the last two ice ages. It is quite fertile, as the rock is dissolved by the rainwater and minerals for the use by plants are set free. The fertile loess was obviously the reason why the first farmers settled here.

The basement of the loose sediments is limestone, actually chalk, which is a variety of limestone which has a very high porosity and is this quite soft. Typical for the chalk are bands of flint, which form rather thin structures in the otherwise more or less homogenous chalk. These are not seams or layers in the common sense, the chalk actually continues across the flint, the flint is embedded into the chalk, but only in certain planes. Those flints form typically huge irregular nodules with sizes up to one meter and a thickness of 20 to 30 cm. Flint is formed when silicic acid or quartz precipitates in limestone. This is a result of the high porosity, the small amount of quartz based fossils in the chalk, and the changing chemistry of the groundwater. The groundwater dissolved the quartz all over the rock and at certain levels the changes in the eH/pH value of the water caused the precipitation.

The erosion cut not only through the chalk but also through the flint layers and so the ground was littered with flint. But the flint was altered by the weathering and flint from underground was of much better quality, which was probably the main reason for the mining.

Description

The Prehistorische vuursteenmijnen van Rijckholt-St. Geertruid (Flintmines of Rijckholt-St. Geertruid) In a forest about 500 m east of Rijckholt, flintstone mines of Neolithic age were discovered. Charcoal found inside the mines allowed C14 dating to 3150 (±60) before Christ. The mines are thought to have been used between 3950 and 2650 before Christ.

The mines were first discovered in 1881 by the Belgian archaeologist Marcel De Puydt (*1855-✝1940), and because of the location close to the Belgian border they were first explored by Belgian scientists. He made the discovery during a train ride in 1881, where he noticed that the landscape between Eysden and Gronsveld, looked quite similar to that of a number of sites of prehistoric materials in the provinces of Liège and Namur. He investigated and found a large number of flints. In 1887, he discovered an oval bowl-shaped area of 54 m by 37 m, which was covered by pieces of flint in a thickness of 1-1.5 m. They were in various stages of processing, and there were many flint flakes, so there was obviously a sort of prehistoric production site. However, the source of all the flintstone was unknown.

The Liège Professor Joseph Hamal-Nandrin (*1868-✝1958) explored the area from 1903 to 1953, for 50 years, and his discoveries are published in countless publications. His collection is today housed in the Royal Institute of Natural Sciences in Brussels. He discovered numerous filled in mine shafts on the surface in 1910, and the first mine passages in 1914 by digging in the slope of the ravine Schone Grub.

The first excavation by Dutch archaeologists Prof. Dr. van Giffen and Dr. v.d. Sleen from Liège started in 1923. The excavated for about a decade, and were able to convince the French Dominican Fathers, who then resided in Rijckholt, to take part in the exploitation on a large scale. Unfortunately a huge part of the findings were later lost due to a lack of interest from the Dutch Dominicans.

In 1964, Prof. Dr. H.T. Waterbolk from the Biological Archeological Institute of the Groningen University explored the whole area and discovered numerous shafts up to 1540 m from the original discoveries. The logical conclusion was, that this is not just a few shafts, it was a mine filed. The Prehistoric Flint Mines Working Group of the Dutch Geological Society, Limburg Section, consisted of volunteers, most of them working as miners in the nearby coal mine. The carried out excavations of flint mines at Rijckholt-St. Geertruid. Soon they had the idea to build a 150 m long tunnel which cut through the mines and allowed to examine them. From this tunnel they excavated mines on both sides for about 10 m, tunnels which were often backfilled almost to the ceiling by the prehistoric miners. 75 shafts in the area were the original access to 1,526 m² of horizontal galleries. It revealed 14000 flint tools including picks and hammerstones, some deer horn picks, charcoal and a human skull. 43 voids are interpreted as wooden shafts which decomposed and left only the impression. Thousands of snail shells were found, which give some glimpses of the surface, at the beginning there were mostly snails living in forests, at the end there were mostly snails living in fields. If the deforestation was a result of mining or the increase of farming is unknown. Nevertheless, this excavation covered only a very small part of a minefield which is thought to have at least 8 ha.

The mines followed layers of flint in Cretaceous chalk, which is locally called Mergel. To reach the most lucrative layers, and because the quality of the flints inside the rock was better than weathered flint found on the surface, the people made much ado to mine them. They first constructed vertical shafts about 10 m deep and 1 m in diameter, then they followed the almost horizontal layers into various directions and constructed a star like tunnel system. This is an ancient predecessor of the room and pillar technique. The first tunnel was excavated and the material transported up the shaft, later the material was removed and then stored in mined out shafts, which made the mines more stable. Some passages end after a few meters, others have branches. However, they are only about 60 cm high and were obviously mined lying and crawling on the floor. Several mines are connected, which allowed the miners to escape through the other shaft in cases of collapse. It also meant additional air and light in the mine. No remains of light sources have been discovered, so the miners worked without light using only the sunlight, which was reflected by the bright white chalk walls.

During the excavation the modern tunnel was used to reach the historic mines, but also to remove many tons of debris. The mines were cleared from the original Neolithic filling, so they became unstable. After the excavation the mines were cleaned and secured by steel struts and joints. The entrance section of the modern tunnel became unstable and was thus supported by steel and concrete beams. For a permanent solution the mine was closed 2021-2022 to build a new entrance tunnel from the side, and the original entrance is now sealed. They also created huge windows into the prehistoric mine which are much better than the original windows. Also, the number of tours was dramatically increased, though they are now only offered for four months during summer.