Recording the menaced mines of the striped flint

Recording the menaced mines of the striped flint with non-invasive methods.
The final of the project realized by SNAP Warsaw Unit.

Author Witold Migal

Group of explorers from SNAP Warsaw Unit, leaded by mgr Witold Migal (PMA) and dr Janusz Budziszewski (UKSW) has finished analyses connected with non-invasive survey of five chosen mines of the striped flint. These mines were founded in the early Stone Age (Neolithic Age) and early Bronze Age, often laid in forest and distinguishing themselves with the founds on the surface – e.g. pieces of worked flint, crumbs or even fragments of two- or foursided axes. Sometimes these mines (just like the most famous mine in Krzemionki) still keep their original over-mine landscape with heaps and pits overgrown the forest.
Many of these sites however was in various periods cultivated and so they no longer have their original landscape. That is why their proper surface and shape are known often only in the approximation.
 Except for the most well-known mine in Krzemionki Opatowskie, archaeologists have discerned several different sites, where in the past the flint was explored. Unfortunately, during last few years, the striped flint has became very popular as a jewellery and the ancient mines happened the aim of the illegal exploitation. This brought to considerable destructions in several cases. To control this phenomenon and make coherent system of protection, the new programme of study and conservation was arised. It's main aim is to collect data about current conditions of the striped flint mine sites. The programme is coordinated with the recognition of the whole mine region with LIDAR system, which is part of UKSW studying programme. Essential component of this project is also geophysical survey, provided by private firm Proton-Archeo from Cracow. Total area of 50 hectares (or even more) of mines and their surroundings was prospected and analysed.
This year project included five sites, which represented the various condition of preservation and was the most menaced be the striped flint seekers.
 The aim of the applied methods of survey was:
- the most exact qualification of ranges of ancient mining fields, that is assembly of sites
where the shafts were digged to reach the flint stratum.
- qualification of mining methods with analysis of each case, from shallow vertical pits,
 to shafts which depth was several meters and with system of the horizontal corridors.
- qualification of the condition of preservation on the present day.
 At the same time the survey methods were chosen. First was the GPR (Ground Penetrating Radar) to locate underground emptinesses and places with different structure e.g. rubbled pits or mine shafts. Next was the resistivity survey. Places with rubbled pits or shafts has different soil conductivity than the surroundings. Last was magnetometer, which is using to locate places that cause magnetic disturbances, as a result of human activity e.g. fireplaces. This method helps with detecting settlements near the mines. Moreover, the model of helicopter with camera connected to it, took the photos of mine area, from the high of approx. 20m. - it will help to estimate the changes of mine surface, caused by illegal flint seekers.
 The result of combined geophysical methods are maps of mine region with the ranges of each mine. They can be compared with maps, that were made while surface survey.
 In few cases it was possible to define on the ground surface the proper mine shape (when the area of mine was smaller than it was shown by the spread of the flint material on the surface or when part of the pits and shafts was levelled). But it was also possible to look under the ground and find the structures, that are hidden there. Although standard archaeological excavations allow us to get accurate knowledge about specific part of the site, they don't give a view of this site as a whole.
 It is necessary to remind that interpretation of geophysic data couldn't be possible without many years of studies and standard archaeological excavations in the flint mine complex in Krzemionki. Advantage was also experience, gained during geophysic surveys in different flint mine sites, that were piloted by IAiE PAN in past years. Current survey was organized and partly financed by SNAP Warsaw Unit and subsidized by MKiDN programme "Dziedzictwo Kulturowe / Ochrona Zabytków Archeologicznych”. Complete results of this survey are available in NID, SNAP Warsaw Unit and Provincial Warden Office in Kielce. For preservation of particular mines, the data about their location won't be given.

Fig. 1. Aerial view of Borownia mine. In central part oblong outline of the mining field.

Fig. 2. Two neighboring mines in Ruda Kościelna. With the support of geophysic methods, it
was possible to discern their ranges and mining technics (deep shafts - approx.6m –
with corridors). Ranges of mining fields after verification are marked with green,
dashed line. None of these mines were visible on the surface.

Fig. 3. Results of survey in Borownia mine in Ruda Kościelna. This site was partly cultivated
 since XIX cent. and original landscape wasn't preserved as a whole. It was essential to
qualify proper range of mining field and the surprise was, that it was a group of two
different mining fields already divided in the ancient times. The mining technique was
the same - horizontal pits, 5-6 meters deep. The map shows results of resistivity survey
combined with background from  LIDAR view (from UKSW project). The mines not visible on the surface are marked blue.

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