What is "snolab"

SNOLAB is a Canadian underground physics laboratory at a depth of 2 km in Vale's Creighton nickel mine in Sudbury, Ontario. The original Sudbury Neutrino Observatory (SNO) experiment has ended, but the facilities have been expanded into a permanent underground laboratory.

Although accessed through a mine, the laboratory proper is maintained as a class-2000 cleanroom, with very low levels of dust and background radiation.

SNOLAB is the world's second-deepest underground lab facility; its overburden of rock provides 6010 metre water equivalent (MWE) shielding from cosmic rays, providing a low-background environment for experiments requiring high sensitivities and extremely low counting