Greenside mine in Glenridding, Cumbria was one of the deepest mines in the UK. After the second world war, it was used as a testing site to establish whether simulated nuclear explosions, deep underground, could be detected from distance by seismometer.
The tests proved that, if properly sited within caverns, the seismic trace would be undetectable within a relatively short distance. The results of the test were rushed to diplomats negotiating the treaty banning nuclear tests, as officials realised the limitations of this step.
