The 14.4-Mt Lalor copper-zinc-gold deposit situated in the Flin Flon Greenstone Belt of north-central Manitoba is large () but deeply buried () and was discovered using deep penetrating ground fixed-loop time-domain electromagnetic (EM). Results from three different airborne EM surveys over a five-year span permit comparisons of the system responses over the Lalor volcanogenic massive sulfide deposit region, assisted using 1D-2D-3D inversions. In late March, 2007, soon after its drilling discovery, Hudson Bay Exploration contracted Geotech to fly helicopter versatile time-domain electromagnetic (VTEM) surveys over the region west of Snow Lake, Manitoba. The deposit was not detected due to its large depth of burial () and the lack of magnetic response. In 2009, Geotech carried out a helicopter z‐axis tipper electromagnetic (ZTEM) passive EM test survey over the Lalor deposit, which was successful and led to a larger survey over the area. In 2012, a second VTEM survey test was flown, using the more deeply penetrating system. Although it had sufficient penetration to detect the orebody, on-site mine-site development appeared to overprint the deeper deposit response. However, a deep () conductive anomaly from a stringer sulfide occurrence, known as South Bull’s Eye, which lies south of Lalor, was well resolved in the ZTEM and surveys.