The application of geophysics to Nickel Laterite resource evaluation.
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
With the dramatic growth of interest in nickel laterite resource exploitation, fueled by increasing demand and new processing technologies, the need for accurate resource delineation and careful mine planning becomes paramount. The traditional use of borehole grids to calculate mineral resources has proven to be neither sufficiently accurate nor cost-effective at many sites due to the complexity of tropical weathering profiles. Although an unconventional approach to laterite mine planning and resource delineation, emerging near-surface geophysical methods, particularly ground penetrating radar (GPR), hold tremendous potential for addressing project geology, resource delineation, and mine planning issues. GPR acquisition and processing techniques have been developed specifically for laterite applications and have been successfully utilized in the field. Preliminary test work has been performed at varied sites in Papua New Guinea, Indonesia, Venezuela, Guatemala, the Philippines, and Brazil. Two projects in New Caledonia were selected as comprehensive test sites for experimentation with GPR. Test surveys with GPR were performed at these sites to determine the effectiveness of the method in mapping the lateritic weathering profile. A description of the geology of various humid laterite deposits and the geophysical consequences of their complex nature is discussed, as well as the correlation of the acquired geophysical data to geological borehole information. Geophysics in general, and GPR in specific, has been proven to increase the database of knowledge with respect to project geology, as well as provide invaluable assistance in mine planning by high resolution imaging of the bedrock depth and texture as well as the accurate location of subsurface pinnacle structures at many sites.