Description
In Twente there is a layer of rock salt at a depth of 350 to 500 meters. Since 1933, salt has been extracted by AkzoNobel in the vicinity of Hengelo and Enschede. Clean water is pumped down, after which brine is pumped up (solvent mining). The province of Overijssel, advises on permits from the State for salt extraction. This advice is aimed at making the salt extractions have as little impact as possible on the structure of agriculture, nature and landscape. It is not excluded that new winning locations will be needed in the future. Given the natural conditions in the subsurface, the search area for future extraction sites is within a radius of 25 km of the current salt extraction area.
Salt extraction in Overijssel has created more than 200 hollow spaces (caverns) in the layer of rock salt. In the past, these caverns have often been made too large or too high or too close together. In addition, there is a risk that the topsoil will subsid or - in the worst case - collapse. In Overijssel there are 63 salt caverns potentially unstable, 22 of which pose such a danger to their environment that stabilization is necessary. AkzoNobel is investigating how these unstable salt caverns can be stabilized. One option is to fill the caverns with so-called slurry and let them harden. The overlying rock layers can no longer collapse in this way. The trial will be carried out together with the Ministries of Infrastructure and Environment and Economic Affairs, State Supervision of Mines, the municipalities of Hengelo and Enschede and AkzoNobel. The trial is included in the National Waste Management Plan (LAP). From 1980, salt is extracted according to a different methodology, the caverns that have been built since that time are stable.
Resources
| Name |
Format |
Description |
Link |