The uses of satellite imagery for mineral exploration include background images for infrastructure planning, environmental impact studies, grassroots exploration and ground access, spectral processing to delineate potential exploration targets and digital elevation model generation.
Satellite imagery can be used to provide background imagery at scales from 1: 2,500 to 1: 1,000,000 and broader. Very high resolution imagery from Worldview-1, QuickBird, GeoEye-1 and IKONOS produces background imagery down to 1: 2,000 and at the other end of the scale, medium resolution imagery such as Landsat and ASTER can be used to produce broad scale regional coverage. When accurately located to ground using control points and seamlessly mosaiced, this background imagery can be used within GIS software for minesite planning, access to utilities, drill hole placement or as a true ground image for both accessible and inaccessible or remote locations.
Landsat TM and ASTER sense in wavelengths useful for the identification of alteration associated with mineralisation. Landsat TM includes a shortwave infrared band in the 2.08 to 2.35 nm range which can discriminate rock types and map hydrothermal clays and the visible bands can be used to map iron oxides. ASTER senses in two visible, one near infrared, six shortwave infrared and five thermal infrared bands, allowing discrimination of epithermal clay minerals, iron oxides, silica, carbonate, mafics and propylitic alteration.
Digital Elevation data derived from WorldView-1, IKONOS, GeoEye-1, ALOS, ASTER and the Shuttle Radar Topography Mission can be used for hydrological studies, utilities management and placement, natural hazard assessment including flood susceptibility and emergency escape access, environmental impact studies, property access, alluvial flow directions and slope and delineation of rock types based on outcrop.
Geoimage are also specialists in producing pseudo-stereo and stereo hardcopy for structural interpretation. We have developed software to produce left and right looking stereo images using available digital elevation models and imagery from a variety of spaceborne sensors.