Metodologia para estimativa de recuperação de lavra em rochas ornamentais, baseada na modelagem de descontinuidades estruturais.

Abstract

Many mineral deposits are abandoned, after the exploration step, due to adverse geotechnical factors. These unsuccessful entrepreneurships end up representing financial losses to companies and environmental damages which may be avoided, i f a previous research is conducted. In the extraction of ornamental rocks, preserving the entireness of the rock is a fundamental factor to completely exploit a deposit, maximizing the reserves and increasing quality and commercial value of extracted blocks. For this reason, as it is a risky activity, it is necessary to be more precise in the prospective phase of the research for the quarry of those areas, in which low knowledge of geological and geotechnical aspects of the studied regions may compromise the exploitation The modeling of the geologic and geotechnical uncertainties started to be one technique of great utility in the sector of ornamental rocks, since its applicability results in a detailed knowledge of the risks which affect the deposit. With base in characteristics as faults, joints, fractures and mineralogical alterations, it was developed a methodology applicable to deposits of ornamental rocks which is able to represent discontinuities in three-dimensional graphics and calculation of the probable recovering of the quarry. The application of the methodology in a study of case real made possible a planning of more versatile plowing, providing the creation of sceneries with the planning parameters, and allowing of that form larger speed and precision in the analyses and in the control of quality of the quarry. The application of this methodology to a real study case allowed the elaboration of more versatile exploitation plans of deposit, making it possible to create settings with planning parameters, decreasing the time required to analyse and increasing the certainty of the analysis in the exploitation quality control of the deposit. The study case was conducted in an area located in the State of Paraiba, in Picui County. It is an ornamental granite deposit, consisting of large-ovalshaped rocks, as well as rock mass outcrops. The deposit presented breakings of different types and height. Therefore, it was an excellent place to conduct a study to contribute to the development of a methodology able to help entrepreneurs of the sector of ornamental rocks to decide how much to invest in researches to exploit areas with similar risk profiles, increasing the quality and profitability of the entrepreneurships. The methodology was proved efficient, permitting a higher control of economical risks, thus, beyond the isolation of the areas in which there were breakings, it also permitted the assessment of the theoretical recovery of the usable areas, being worthwhile to future works in the sector of ornamental rocks.