An underground UHF-EM transillumination experiment at the big nickel mine in Sudbury, Canada

The Geophysics Laboratory of McGill University investigated the use of UHF-EM transillumintion measurements in geophysics through the construction of a prototype 445-MHz continuous-wave transillumination instrument designed for underground use in geophysics. Test surveys with this instrument were conducted at the Big Nickel Mine in Sudbury, Ontario, to obtain through-rock electromagnetic absorption rates. Measurements were made at several sites between underground drifts and the surface. The results of the field surveys indicate that the UHF-EM transillumination technique is feasible and, under strictly defined field conditions, can provide useful information on the in situ electrical properties of rocks.