Contribuição de SIGs para a gestão e planeamento de recursos geológicos

Resumo

THE CONTRIBUTION OF GIS TO THE PLANNING AND MANAGEMENT OF GEOLOGICAL RESOURCES. The exploitation of geological resources, and of dimension stone in particular, is an important industry in Portugal -this country ranks 5th place in the world list of dimension stone producers (Montani, 2001). This paper presents an application of a Geographical Information System (GIS) to the management and planning of geological resources based on an example from the Santa Eulália Granitic Massif, which is located in one of Portugal’s main production centres – the Alentejo region.The construction of the GIS database took into consideration two different types of information: “background information” such as topographical maps, aerial photos and Municipal Management Plans; and “geological-mining information” such as the main exploitation areas, the definition of commercial types and the characterization of the quarries, including geographical positioning, licensing, exploited commercial type, photographic coverage, rock fractures, samples, mineralogy and geochemistry, among others.In order to demonstrate the applicability of this tool, several examples of possible outputs aimed at meeting the specific needs of different types of end-users are provided. Outputs for exploiters, land planners (such as local authorities) and builders and architects can be obtained by defining the type of information that each would find relevant for their respective business.The application of GIS to the dimension stone industry plays an undeniably important role in the modernization of an economic sector that faces, and needs to be prepared for, fierce international competition. This GIS approach may be considered an extension of the application of the Best Available Technologies (BAT) principle to the environmental concerns of the dimension stone industry. It will certainly contribute to the adaptation of this sector to the new reality that has arisen from the requirements of the new Portuguese quarrying legislation (Decreto-Lei 270/2001).The demonstration of the potential of this GIS applied to the Santa Eulália Granitic Massif suggests the usefulness of developing similar approaches in the case of other regions. At present, the construction of a GIS database comprehending the Estremoz Marble Zone is already under way, as both background and geological-mining information for this region is already being collected.