Geotecnologias para avaliação de impactos ambientais causados pela atividade mineradora na cidade de Pedra Lavrada-PB.

Abstract

Virtually all mining activity involves removal of vegetation or impediment of its regeneration. In many situations, the most fertile portion of the soil, the top, is also removed, and the remaining soils are exposed to erosion, it may cause siltation and even contamination of the water bodies at surrounding environments. Thus, this study aimed to evaluate the environmental impacts caused by mining activity in the municipality of Pedra Lavrada - PB. To collect environmental data, tables were prepared according to the methodology used in the standard ISO 14001 (ABNT, 2004d). For the study of the radiometric data were used seven images on different dates, from the Thematic Mapper (TM) sensor, orbit and points 215/65 on board Landsat 5 satellite. Yet, in field activities a Garmin GPS model Etrex Vista HCX was used to collect coordinates from individuals point used on spectroradiometry data. The samples characterizations from benefited products at the mining activity areas (syenite and feldspar) as well as, the land cover data in the vicinity of these areas, were made through particle size analysis by laser diffraction (LD), chemical analysis (CA) and X-Ray Diffraction (XRD). The main environmental impacts caused by mining activity in the municipality of Pedra Lavrada - PB are the destruction of natural vegetation; handling and exposure to soil erosion, dust generation, noise and gas emissions; resulting in scaring the fauna and flora and waste generation for water resources. Through Albedo surface map and Vegetation Index adjusted to Soil was observed that the environment surroundings the Industries Processing Facilities are highlighted with higher albedo values and lower UAI. The areas used for feature extraction albedo values exceeding 0.301 and ARI values ranging between 0 and 0.10. It was also possible to observe significant changes in land use and land cover surrounding Pedra Lavrada Township and differences in reflectance values of the spectral curve on individuals affected by mining activity waste. The characterization of the land cover material in the vicinity of processing facilities more specifically syenite and feldspar, showed that they were hit directly by the residual dust generated by soil tracks downwind up to 400m and 200m respectively. The chemical and mineralogical composition of the soils surrounding the syenite and feldspar facilities showed that they theoretically are not feasible for use as raw material on white ceramic production because of its high iron content (> 2%). The waters stored in mining digging open pits extraction at the one of the evaluated plants (Mining A) can be used for human and animal consumption as well as for irrigation projects and family basic needs.