INVESTIGATION ON AN AIRBORNE MAGNETIC AND HELITEM SURVEY ON FLIN FLON AREA

Abstract

Over the past two decades, application of airborne time domain electromagnetic and magnetic technology has seen increased use in mineral and hydrocarbon exploration, ground water and environmental investigation, largely due to the characteristic that a moving platform is able to perform accurately and efficiently even in a varied and rough topography. The helicopter-borne time domain electromagnetic system (HELITEM) is a new generation system designed and operated by Fugro Airborne Surveys. It has much larger peak current as well as peak dipole moment and later first gate compared with other airborne time domain electromagnetic (EM) technologies such as SkyTEM, VTEM and AeroTEM etc. Few studies has been published on HELITEM system. BFR Copper & Gold Inc. has made available a large HELITEM and magnetic survey of a volcanogenic massive sulfide (VMS) project in the Flin Flon area to be the data source of this study. The induction of coil coupling over static geomagnetic field is firstly studied to determine if that would corrupt EM data, especially late gate signals. VMS targets are expected to be both conductive and magnetic. There are many examples of coincident magnetic and conductive anomalies in the data set. Therefore, coincident magnetic and conductive anomalies are searched to indicate target areas. Subsequently, forward and inversion plate models are created using modeling software Maxwell which was developed by ElectroMagnetic Imaging Technology (EMIT). Radial Spectrum method and tilt derivative method are applied for depth estimation using magnetic data and the results are compared with inversion models to find consistency and further determine whether the potential conductors should be investigated further. The object of this research is to refine the search indirectly to determine which magnetic and conductive anomalies are coincident in depth as well as geographic location. Plate modeling on some of the more attractive targets is attempted to refine their depth, depth extent, size, shape and conductivity.