Structural, physical and compositional proprieties analysis of mra arbles in a quarry face: a study case application on Estremoz Anticline

Abstract

The application of scientific and technological research activities to innovation and to social and economic development is one of the great challenges of contemporary times. Such aspects are even more significant in the industrial sector, because the R&D activities can have a remarkable impact on the sustainable production of raw materials and on the economic viability of companies. Indeed, the development of innovative and expeditious scientific and technological methods, which can reply to the usual and specific challenges of the exploitation, manufacture and transformation of dimension stones, are extremely important in the business dynamics. The Estremoz Anticline is one of the most significant active poles of the extractive industry in Portugal, being one of the main marble-producing poles at the European scale. The extractive activity takes place in the three municipalities of the so-called Marble Triangle (Borba, Estremoz, Vila Viçosa), exploiting calcite marbles from the Estremoz Volcano-Sedimentary Carbonated Complex, whose geological age has not been fully clarified (Cambrian to Devonian ages were attributed to this unit). The marble exploitation, manufacture and transformation is one of the main drivers of development in the Marble Triangle, presenting great local and regional socio- economic significance. Beyond this, it is also central to increase the rock coefficient of utilization (20-25% in Estremoz marble quarries) in order to decrease the volume of wastes and increase the marble productivity in this region and therefore marble’s production sustainability. Indeed, in order to support the raw material exploitation process, the management of mineral masses and the potential rock coefficient of utilization and blockometrics, detailed geological mapping of quarry faces were carried out. These detailed geological mapping include: (1) Lithological and structural characterization of quarry faces, including detailed characterization of the existing lithotypes, their mineralogical composition and lateral variations of marble typologies, as well as the geometric and kinematic detailed characterization of the main structures, namely foliation, shear zones and fractures, including the density characterization of fracturing; and (2) In situ evaluation of aesthetic, compositional and physical-mechanical features of marbles, using multiple portable equipment’s (e.g. X-ray fluorescence, colorimeter, Schmidt sclerometer). The application of this innovative and expeditious methodology, using a fine sampling matrix of the vertical and horizontal quarry faces, allowed the construction of detailed two- and three-dimensional maps, which could allow better management of the extractive activity.