Organizers of the PDAC convention have requested that Jan Francke to speak during the invited sessions on geophysics. The title of the talk will be “Advances in Geophysics for Resource Modeling of Nickel Laterites”. A number of geophysical applications to laterites will be covered, including regional airborne magnetic and electromagnetic surveys, ground EM, resistivity (ERT) and IP approaches, and long-range GPR applications. Numerous case examples will be provides from laterite projects on all six continents.
Groundradar was contracted to conducted borehole tomography surveys at a nickel laterite project in New Caledonia. Borehole tomography provides one of the highest resolution views of the subsurface, and reveals a number of important soil and rock parameters such as radar velocities, and attenuations. Using the Topp relation, water saturation and porosity may also be derived from the tomographic cross-section. Borehole surveys are also commonly applied in the detection of un-mapped tunnels in open pit mine sites.
Jan Francke has co-authored a paper entitled “Application of advanced ground penetrating radar technology for abandoned working detection at Geita Gold Mine, Tanzania”. The paper, to be presented at an AngloGold Ashanti conference in September, 2009 discusses the use of UltraGPR to image abandoned workings at an open pit operation in Tanzania. UltraGPR was able to detect a series of voids at a coverage rate of one hectare per day with one metre-spaced profiles.