In september 2017 is Joep Orbons als archeoloog afgestudeerd aan de Universiteit van Amsterdam. Voor de studie is een scriptie gemaakt over de mergelgroeven als archeologisch onderzoeksterrein. Deze studie in het engels heeft de titel "An Archaeology of the Darkness, Man-made underround srtuctures in the Mergelland region as a source for archaeological studies", is hier gratis te downloaden. De studie is Engelstalig, heeft 116 pagina's, 11 bijlagen en 88 afbeeldingen in full colour.

Orbons, P.J., 2017, An Archaeology of the Darkness, Man-made underground structures in the Mergelland region as a source for archaeological studies.

De studie is ook als boekje te bestellen tegen betaling van 25.00 euro plus verzendkosten op onderstaand adres:

St Jozefstraat 45
6245 LL Eijsden

Tel: 043 3672586


In September 2017 Joep Orbons graduated as archaeologist at the University of Amsterdam. For the study a Master-thesis was made regarding the underground limestone quarries as an archaeological field of studies. This study in English has the title "An Archaeology of the Darkness, Man-made underround srtuctures in the Mergelland region as a source for archaeological studies", and can be downloaden for free. The thesis is in English and has 116 pages, 11 appendices and 88 figures in full colour.

Orbons, P.J., 2017, An Archaeology of the Darkness, Man-made underground structures in the Mergelland region as a source for archaeological studies.

The Master thesis can also be ordered as a booklet at the cost of 25.00 euro plus P&P at the address below:

St Jozefstraat 45
6245 LL Eijsden
The Netherlands

Tel: 00 31 43 3672586



Orbons, P.J., 2017, An Archaeology of the Darkness, Man-made underground structures in the Mergelland region as a source for archaeological studies. Master thesis Archaeology University of Amsterdam. Amsterdam


The goal of this study is twofold. First, it is shown that the man-made underground structures in the Mergelland region may be regarded as legitimate archaeological features. Second, it is to demonstrate that conventional archaeological research methods and regulation may be applied to investigate and further our understanding of these underground structures, thereby providing a suite of archaeological techniques to encourage future studies.

At first an overview of the man-made underground in the limestone of the Mergelland region is given.

The oldest are the Neolithic flint mines that are found on many different locations and are well studied by archaeologists and are regarded of international importance. Although many studies have been carried out, there are still questions that can be studied.

Another type of underground are the chalk mines. Only a couple are identified as old chalk mines but their date is unknown. It can be Neolithic, Roman, early medieval or medieval. More research is needed.

The largest number of underground sites are the limestone quarries for building stone. There’s 525 kilometres of galleries in over 400 individual quarries with more than 850 entrances. The oldest quarries are not determined, maybe Roman, maybe medieval. But from the 12th century onwards, there is evidence of underground quarrying for building stone. From the 14th to the 19th century the quarries produced high amounts of building stone. In the 20th century the underground quarrying declined but never completely disappeared as one quarry is still active.

But the Mergelland region offers more underground in the limestone. There are road tunnels, train tunnels, transport tunnels, shelters from the Second World War and a couple of horizontal water wells.

All of these underground sites have had an active secondary use as mushroom growery, storage or tourist attraction. All of these activities left their traces and can be archaeologically studied.

Secondly archaeological research methods are applied to these underground sites.

A predictive model for entrances and underground galleries was made for one parish (Valkenburg) using geological maps, LIDAR data and historical maps. The combination of these data sets resulted in a predictive model of the quarries with a 98% accuracy. The model is translated to a policy map for the local council to use in their management.

The GIS as a historical analyses tool has been applied to the quarries to get some basic statistics and estimations. The total amount of limestone quarried has been Chapter 6 Conclusions 77 78 An Archaeology of the Darkness estimated. From this figure, an estimation is made about the number of quarrymen working underground through the ages therefore positioning the craft of quarrymen in a historical context.

The GIS data was also use in one quarry to visualize the extraction progress resulting in periods of high production and periods of low production. These could be linked to geological variations in the limestone and to demand for buildingstone. LIDAR data and geophysical measurements are important datasets and tools in archaeological prospection. They can also be useful to find quarry entrances and position quarries and understand the extend of a quarry but does have its limitations.

The Dutch law, regulations and research agenda does not include quarries as a feature but the quarries and other underground structures can be included in the regulations and the law applies to them. The Dutch research agenda does have a couple of research questions that do apply to the underground sites but a series of additional research aims and questions are proposed.

It can be concluded that the man-made underground sites in the Mergelland region are archaeological sites, that archaeological research methods can be applied to them and that from a legal and regulation point of view, things are well organized but the research agenda needs some additional research aims and questions. These sites form a good connection between historical sources and material sources. Concluding that the quarrymen of the past working underground created an archaeology of the darkness.



1 Introduction
1.1 Aims and goals
1.2 Research question: Do man-made underground structures qualify as archaeological features?
1.3 The organization of this thesis

2 Underground in Mergelland
2.1 Geology, archaeology and history of the Mergelland region
2.2 An overview of the man-made underground structures in Mergelland
2.2.1 Flint
2.2.2 Chalk mines
2.2.3 Limestone quarries
2.2.4 Horizontal water wells
2.2.5 Tunnels
2.2.6 Second World War shelters
2.3 Secondary use

3 Predictive model of underground limestone structures
3.1 Introduction
3.2 Predictive model for quarry entrances
3.2.1 Geology
3.2.2 Elevation and slope
3.2.3 Historical settlements
3.2.4 Predictive map of quarry entrances
3.3 Predictive model for underground galleries
3.4 Quarry policy map

4 GIS data analyses
4.1 Numbers and figures
4.2 LIDAR analyses to find entrances and quarries
4.3 Geophysics to trace entrances to quarries

5 Archaeological regulations and research agenda
5.1 Archaeology in the Dutch Erfgoedweg 2016, KNA 4.0, NOAA 2.0
5.2 Man-made underground in Erfgoedwet
5.3 Man-made underground in KNA
5.4 Man-made underground in Dutch research agenda NOAA


Appendix 1: Terminology used in this thesis
Appendix 2: Overview of research to man-made underground sites outside Mergelland region
Appendix 3: Geology of the Mergelland region
Appendix 4: Archaeology and history of the Mergelland region
Appendix 5: Discovering the Rijckholt Flint mines
Appendix 6: Overview of research and publications carried out until 2016
Appendix 7: Henkeput
Appendix 8: Amstenrade castle
Appendix 9: Extend and inventories of the quarries
Appendix 10: Features relating to the underground quarries
Appendix 11: Tunnels in the Mergelland area

List of figures


Souterrains    St Jozefstraat 45    NL 6245 LL Eijsden    Tel: 043-3672586     e-mail:, gebruik liever mijn ander email adres: www:
ING bank: NL77INGB0008980640    BTW nummer:
NL001822687B45     Kamer van Koophandel: 14066883