Geophysics

Inversion of the high-resolution magnetic over the Mud Lake kimberlite has been carried out. This work suggests that the intersected flat lying kimberlite dyke may in fact be part of a much larger steeply dipping pipe-like body.

The inversion of the magnetic data was carried out using MAG3D. This program is part of a suite of algorithms developed at the UBC Geophysical Inversion Facility. The work itself was carried out by Trent Pezzot P.Geo of CJ Visser Geophysics using MAG3D.

Essentially, magnetic inversion is a process whereby a series of possible geological structures are generated, each until a "best-fit" between the observed magnetic field and the theoretical field is obtained.

The MAG3D program allows you to look at the 3D model from all angles and remove "outside" data, thereby allowing one to "look inside" the model.

Below are some "snapshot" images taken from the Mud Lake inversion. Click on a thumbnail and a larger image will appear in a new window.

A detailed gravimetric survey has been completed at Mud Lake. The presence of a larger kimberlite body (as suggested by the inversion of the magnetic data), as opposed to a thin, flat-lying dyke-like body, would generate a distinct gravity signature. Such a signature would be dependent on there being a sufficient density contrast between the kimberlite and the granite host. Modeling of the gravity data will provide further structural information on the kimberlite and assist in the drilling program. All of this work is directed towards the ultimate purpose of establishing where to take the 500 tonne bulk sample.

Snowfield’s holdings in the Ticho Diamond Project area exceed 40,000 acres. Prior to acquisition by Snowfield the area had already been covered by airborne magnetics. This magnetic survey was carried out using a line spacing of between 100 and 200 meters.

Snowfield has re-flown the entire area using a sophisticated, state of the art helicopter borne electromagnetic (EM) system. The survey utilized Meridian Geoscience's Hummingbird Electromagnetic/Magnetic survey system. The system is a multi frequency in-phase and quadrature EM system utilizing three coplanar and two coaxial coils. The coplanar frequencies are 980, 6600 and 34000 Hz. The coaxial frequencies are 880 and 7000 Hz respectively.

The purpose of the EM survey was to establish whether or not the magnetic targets, previously identified, were also EM anomalies. An analysis of this detailed data (50 meter line spacing) appears to indicate that approximately half of the magnetic targets show an EM response. A number of EM anomalies have also been identified with no associated magnetic signature. Further work is planned on this data set. This work will include resistivity depth sections and EM inversion modeling.