Case Studies - Mineral Exploration

Kimberlite Exploration - Field Example- Willy-Nilly

Note the GEOTEM profile in figure 1 shows a "textbook" airborne time-domain response over a kimberlite source. The sharpness and amplitude of the response, combined with the enhanced trailing edge negative, is typical of a conductive flat lying plate.

Figure 1: GEOTEM Profile

An anomalous conductivity zone associated with the kimberlite source is outlined in figure 3 within a background of conductive lake sediments. A 100 nT magnetic low shown in figure 4 is coincident with the apparent conductivity response. The kimberlite target is clearly delineated by the GEOTEM Channel 7 off-time response (figure 5). Note that the response from the lake bottom sediments has decayed to zero.

Figure 2: Anomalies and flight path

Figure 3: Apparent Conductivity (on-time) Contours (mS/m)

Figure 4: Total Magnetic Field Contours (nT)

Figure 5: Channel 7 (off-time) Amplitude Contours (ppm)

A traverse line spacing of 200 metres was flown over the target. In this case a wider line spacing of 250 metres could have been used without losing the capability of target detection or discrimination.