Introduction
ZTEM (Z-Tipper Axis Electromagnetic) surveys were conducted over the Riou Lake Test Block, in the North Athabasca Basin in May, 2008. The ZTEM survey consists of airborne Tipper AFMAG (audio frequency electromagnetics) measurements, as well as aeromagnetics using a caesium magnetometer. The survey consisted of fifty-four (54) 11.5km long, NW-SE oriented flight lines, totaling 621 line-km, that were obtained at nominal 400m line spacings over an approximately 30 x 60km area. The area was chosen because it had been partially flown using VTEM, it hosted significant thicknesses of Athabasca sandstone (500-750+ metres) cover and also because the area’s schematic geology was available on the web and in the public domain.