GIS and Remote Sensing applications empowering entirety of modern mining cycle
Modern mining, a complex chain of inter linked decisions, has been significantly powered by two fold applications of spatial data which are commonly known as GIS and Remote Sensing aided satellite data/images or together as ‘geospatial’. Geographic Information System (GIS) in mining is a multi-information coordination synthesizing all required data/evidences on and about earth for each geographic point locations. Remote sensing derived satellite images provide the ground details varying from very high, high, to moderately high resolutions depending on the purpose and precision required from the surface to near surface of the earth for the specific applications. Starting from due diligence for exploration, exploration phase, feasibility planning, mining operations, and closure with mining reclamation – the entire mining cycle in 21st century is assisted successfully through the intervention of geospatial technology (Figure 1). These approaches are more accurate, cost effective, and time competent.
Figure 1: Modern Mining Cycle and value change through geospatial analysis
GIS helps to reconstruct and archive historic geological maps, toposheets, and other forms of references in a dependable, non-perishable, unbiased, digital format through geo-referencing and digitization. This is an invincible tool to assimilate all information into a common spatial platform in order to provide any spatial decision support system. In addition, GIS also arranges data and creates database as well as relational database management systems. Typically borehole data, geologic, and mineral occurrences database, field data, location analytics, demand supply chain and market analysis, etc. are among some of huge database categories that require systematic data structure. Moreover often preparing maps for field guide, relating GPS point locations from land surveys are closely linked with exploration related projects in mining industry.
Satellite data is useful as optical data (like very high resolution data QuickBird) for site and location analysis (Figure 2), spectral properties of satellite data (like ASTER Terra satellite data with moderately high resolution) is suitable to identify spectral signature of various minerals, rock compositions, lithological variations (Figure 3), and to understand complex geological, geomorphological processes, style of mineralization, and alteration processes on earth surface (Figure 4).
Figure 2: More than Google Earth … more precise! It is QuickBird satellite data (bottom image is SPOT data with about 7 m resolution incorporated in Google Earth Application; top image is processed QuickBird satellite data with about 2.5 m resolution).
Figure 3: Assimilating RADAR data and ASTER Terra satellite data to extract spectral signature for creating lithological units and geologic structure incorporated with information from historic geological map.
Figure 4: Mineral Mapping following spectral signature study and identifying potential zones of Iron Oxide bearing minerals
In addition, pixel analysis through image classifications of hyperspectral or multispectral satellite data helps to extract many hidden and interpretive features of the land which is generally covered under vegetation and soil so that it is easier to detect change in landuse, gradual increase in mining area, impact through pollution, and change in surficial expressions over time (Figure 5). For mining heavy mineral sands along coastal areas we often need to know the sea migrating processes during the course of time. Cartographic element ‘scale’ is an obvious parameter for these applications which determines the appropriate remote sensing method and data to be extracted.
Figure 5: Chronological advances of Lignite mine in Rockdale, Texas over time – assessment for landuse change and reclamation processes (top image is from Google Earth and bottom image is from processed Landsat TM 5 satellite data of different periods of time).
Therefore ,broadly speaking, remote sensing and integrated GIS approaches are dynamic and very much purpose driven depending on the area, commodity/material of interest, and objective of the project – over all stages of a complete mining cycle. The most unique approaches among them are diversified applications as prediction for exploration which include but not limited to study of regional geology, structural mapping like identifying lineaments, faults, local fractures, folds, outcrops, ability to map regolith systematics, plate tectonic activities, regional upliftment and subsidence, finding impression of volcanic activities, delineation of lithological units and their boundaries, elevation change, study of mineral constituents, ore deposits, hydrothermally altered mineralization, large scale rock association, recognizing metallic mineral deposits, reading spectral signature of coal, shale, and other commodities like beach sand, detection of hydrocarbon reserves and its presence in the land and on the sea surface, questioning changes in soil and vegetation cover to identify anomalies possibly related to geologic events/occurrences, describing land-use details to assess exploration tenements, location of tracks, roads, accessibility, fences, habitation, vegetation, agriculture, drainage network, distinct geomorphology, etc. Nearly ‘all minerals of commercial interest’ can be rapidly mapped using different remote sensing imaging systems which are farther validated with the field observation.
Geovale Services Private Limited provides services for acquiring, processing, and interpreting various satellite data products for the powerful decision making solutions. It is more of a magician’s perspective to unearth the real value of earth that makes principles of geospatial ‘science’ an ‘art’ in practice.