Comment on reports about the handling of unpolluted saline water of the Asse mine

At least since 1988, groundwater saturated with rock salt from the adjoining overburden flows into the Asse mine. Currently, the volume amounts to 12,000 litres per day. The major part of these influent solutions is collected in a depth of 658 metres and, following a radiological control, pumped from the Asse II mine to the surface and taken away. However, it is becoming more difficult to dispose of the influent solutions. Because it is difficult to find recipients for the solution – despite it being of no radiological concern.

The solutions from the Asse II mine, which are permitted to be taken away, being of no radiological concern, have so far been taken in regular intervals to the abandoned Mariaglück mine near Höfer in the rural district of Celle. Until 1977, rock salt and potash salt were produced here. Until 2009, the cavities were not only backfilled with freshwater and the rock-salt saturated influent solutions from the Asse mine but also with brines from waste disposal plants. Annually, the BfS has about 3.85 million litres of influent solutions taken from the Asse mine to Mariaglück. Since the mine is to be finally closed in 2014, the BfS must find alternative recipients.

The BfS comments on current reports about the challenges associated with the handling of unpolluted brines in the Asse mine:

1. With the Asse mine the BfS has taken over a relic that needs to be commissioned safely. Currently, about 12 cubic metres of unpolluted salt water flow into the Asse mine daily. For these brines there is currently a recipient in a mine. The BfS must prepare itself for the currently constant inflow rates of these unpolluted waters to rise quickly. Disposing of the waters in a single mine would then not be sufficient and can anyway only be done for a limited period of time. Therefore the BfS must deal with the issue of possible alternatives in due time.
2. So far, the BfS has neither made concrete plans nor submitted applications for discharging unpolluted salt water into the North or Baltic Sea or into rivers.
3. In its statements on disposal options of unpolluted salt waters, the BfS has referred to the basic question as to how to deal with these salt waters in other cases. From the radiological point of view, the salt waters can basically be discharged into the North or Baltic Sea or into rivers. However, prior to such action, the ecological consequences of such a disposal would have to be clarified in a legal licensing procedure.
4. There are different disposal options for the contaminated brines present in small volumes in the Asse mine. Basically, these brines should be accepted by the federal state collecting depot, which has however emphasised that it had not sufficient capacity. To prepare retrieval, alternative disposal options must therefore be examined that are safe and at the same time create the necessary room for the works underground. The alternative options will be discussed with the Asse Monitoring Group beforehand.

The BfS has depicted the challenges in dealing with the unpolluted salt waters flowing into the Asse mine, with contaminated brines and the various basically conceivable disposal options in a chart in the 19th edition of the “INSIGHTS INTO THE ASSE MINE".