The iron ore deposit
The Konrad mine is the youngest of the former iron ore mines in the Salzgitter region. The iron ore deposit of the Gifhorn Trough extends over a length of about sixty kilometres and a width of eight to fifteen kilometres.
The Konrad mine differs significantly from other sites as the iron ore is located in a great depth and it is well isolated from groundwater near the surface. Numerous studies in the scope of the plan-approval procedure showed quickly that Konrad is suitable to host a repository for radioactive waste with negligible heat generation. In about 30 years of operation, about 90 per cent of the German radioactive waste could be disposed of there.
Mighty ore deposit
The Konrad mine is part of the Gifhorn Trough, a wide ore deposit extending from Salzgitter-Hallendorf to the north of Gifhorn. It comprises about 1.4 billion tons of iron ore. It was discovered in 1933 in the process of petroleum exploratory drillings, the ore not reaching the earth's surface at any point. The deposit generated about 150 million years ago in the Upper Jurassic from a prehistoric ocean. Over many million years, more layers were deposited above the ore. The ore horizon itself is between twelve and eighteen metres thick.
Favourable geological conditions
When disposing of harmful substances in the deep geological underground, water is the key transport medium because with it the harmful substances can get back into the biosphere. The Konrad mine is very dry for an iron ore mine. This is due to an up to 400-m thick cover of clay and marl layers that are impermeable to water. This geologically favourable situation was also the trigger for the preliminary investigations in 1975 as to the geo-scientific suitability of the Konrad mine to host a repository.
State of 2017.03.30