Project "Radiological registration, examination and evaluation of mining relics (Register of Relics)"

Since 1991, the Federal Office for Radiation Protection (BfS) carried out the determination of the natural environmental radioactivity originating from mining activities in the new Laender, as a special task due to the German Unification. Therefore, BfS performed the project "Radiological registration, examination and evaluation of mining relics (Register of Relics)" from 1991 until 1999.

BfS project examined mining relics for radioactivity

With this project those uranium ore mining relics which were no more owned by the Wismut GmbH and the relics of historic mining were systematically registered, examined and radiologically evaluated. In detail, these are the following objects:

• Milling facilities (facilities for the separation and processing of the usable material through mechanical, chemical or metallurgical procedures including premises and operational areas),
• Industrial tailings ponds (ponds for depositing residues (tailings) and for cleaning liquid process waters from milling facilities),
• Waste rock piles (landfills of debris having arisen in the process of mining or mechanical ore dressing or of residues from metallurgical processing (slags)),
• Prospects (developments created by mining with low depth and small surfaces to explore orebodies or utilisable raw materials),
• Galleries (horizontal mining drivings),
• Shafts (vertical mining drivings),
• Residual holes, cavities (unbackfilled open pit residual holes or cavities),
• Facilities (non-recultivated operational areas and possibly not decontaminated mining facilities such as ore bins, uranium ore box deposits, water engineering facilities etc.) and
• ore loading places (areas not located on the premises where uranium ore was reloaded).

In addition to this, it was of particular importance to identify the mining-affected areas in the vicinity of the aforementioned objects, for which it is necessary to take measures to reduce or remove the radiation exposure of the population.

Investigations concentrated on suspected sites

As a result of the project, those relics were identified for which radiation exposures above 1 Millisievert (mSv) per year cannot be excluded and for which therefore further examinations and, if necessary, remediation measures or restrictions in use must be taken into consideration.

The examinations concentrated on so-called suspected sites ("Verdachtsflächen") in order to efficiently use the financial means. These were sites with reasonable suspicion of radioactive contamination of the majority of mining objects due to existing information from mining agencies and geological records.

The results of the performed examinations were saved in the A.LAS.KA data base and in the technical information system relating to mining-caused environmental radioactivity (FbU) and were discussed in detail in reports referring to suspected sites. The data and information are available to the authorities of the Laender Saxony, Saxony-Anhalt and Thuringia that are competent for radiation protection implementation.

Parallel to the project "Register of Relics" BfS carried out a measuring programme to examine radiation exposure due to radon in the air. This programme showed that although there are clearly enhanced radon concentrations in the vicinity of mining facilities compared to the natural ground, no large areas are affected. Details are given in the report "Results of outdoor radon measurements in mining areas", BfS-SW-05-09 (in German only).