Remote sensing in the search for metallic ores: a review of current practice and future potential

Abstract

Remote sensing denotes the aerospace practices of measuring the ultraviolet, visible, infrared and microwave radiations emitted and reflected from the surface of the Earth and from the atmosphere. As defined here, remote sensing excludes the more conventional methods of geophysics and geochemistry. Aerial photography, side-looking airborne radar and airborne thermal infrared scanning are remote-sensing techniques that can currently provide the mineral industry with high-resolution data to meet specific requirements at acceptable costs. With respect to mineral exploration, other types of airborne remote sensing are largely experimental. Several systems for remote sensing from satellites can be utilized for mineral exploration. Undoubtedly, the most universally available and most cost-effective type of' remote sensing from the prospector's point of view is multispectral scanning by NASA's series of experimental Landsat satellites. Cloud-cover permitting, these satellites provide repetitive data of moderate resolution at low cost for many parts of the world. Neither airborne nor orbital remote sensing are "stand alone" exploration techniques. Their ef'fectiveness is optimized by integration, in the usual exploration manner, with other sets of data from geological, geophysical and geochemical surveys. While visual interpretation is the most widely used method of' analysis, digital processing can provide improved images, enhancements and spectral discriminations that may meet specific exploration needs. However, digital analysis as a general tool for mineral exploration should still be viewed as largely experimental. While atmospheric attenuation, heavy vegetational cover and "inadequate" spectral and spatial resolutions may cause problems, the major current limitations of remote sensing for mineral exploration are: (1) a lack of' significant penetration below the surface of the ground, and (2) an inability to classify rocks and soils except in a generalized way. Despite these limitations, remote sensing, and in particular the complementary tools of Landsat and aerial photography, can provide much useful information at relatively low cost. The principal contemporary benefits accruing from remote sensing in the search for metallic ores are: rapid regional reconnaissance, access to remote areas, and mapping of geological structures and formational continuity. While discovery of mineralization through both airborne and orbital remote sensing has been reported, such discovery of an economic mineral deposit has not been documented in the literature. National remote sensing programs, both in Canada and abroad, have generally failed to prOVide adequate incentives for essential development of practical applications in contradistinction to strong support for development of technology to generate and process data. In the future, airborne remote sensing will develop as a specialized source of detailed information to meet recognized goals. In particular, aerial thermography will be more widely used in arid terrains. Visual interp...

Geology, Geochemistry and Geophysical Studies in Exploration of Copper and Iron Reserves: A Case Study

“…Geology is the study of the composition, structure, and history of earth processes and their products [4]. Geological investigation relies on various data sources such as field and laboratory studies, geophysics, geochemistry, aerial photography, and remote sensing [5]. The latter represents a critical data source for a variety of geological applications, such as mineral alteration, lithological and structural mapping [6][7][8][9][10][11][12][13][14][15][16].…”

The Contribution of Sentinel-2 Satellite Images for Geological Mapping in the South of Tafilalet Basin (Eastern Anti-Atlas, Morocco)

“…Since the seventies (Bishop et al, 2018a), satellite imagery, with various missions and instruments, has allowed geological mapping to take a big step forward with the use of remotely sensed data. Geological remote sensing that debuted recently (Gregory, 1979)with the use of low resolution images of landsat1; has evolved in parallel with the progression of the satellite programs that followed; like Landsat2 to Landsat8; ASTER and others Multi or hyperspectral satellites, for more details see (("Satellite Missions Directory -Earth Observation Missions -eoPortal," n.d.). Over the past three decades, the use of multispectral data has increasingly permitted determining the nature of minerals and rocks.…”