Shafts, boreholes, etc. will be breached by fractures. The sealing of the shafts and boreholes is immaterial if fractures compromise them. Brine in the down dip rooms compromises the panel seals even though it is not claimed that the panel seals are barriers to movement. The technology of borehole sealing is debatable and has been researched for many years. An experiment to verify the ability to seal boreholes is impossible.
Salt causes corrosion of the sealing materials.
There is an effect of shear on the boundary with stiff and compliant sediments. A small leak along the contact will soon become a solution passage. In Esterhazy, the German consultant said that every potash mine ultimately floods. Ralph Crosser in Carlsbad also said they all leak. Clay seams and anhydrite beds leak water.