Wanderer, as per those 2004 VTEM maps you found on the ministry site:

This is what is mentioned in Kian Jensen's Langmuir 43-101 ( which I am going over agin now)

"The OGS (1988) contracted a combined airborne magnetic and electromagnetic survey over the

Timmins area, which included the whole of Langmuir Township. A number of strong AEM

responses resulting from this survey do not appear to have been previously drill tested. The OGS

(2004) contracted Aerodat to cover the regional area with a helicopter mounted frequency

domain EM system and a cesium vapour magnetometer. This geophysical data was released into

the public domain in 2004, and shows basically the same EM anomalies as the previous airborne

survey."