Characterization and geochemical-geotechnical properties of granite sawdust produced by the dimension stone industry of O Porrino (Pontevedra, Spain)

The dimension stone industry is one of the leading economic activities of Galicia and it is also an important industry in many other parts in the world. During the sawing and preparation of dimension stone, a large amount of granite sawdust is generated. In the O Porriño area alone, located in the southern part of Galicia, c.?300 000 tonnes are produced every year. According to current EU Directives, granite sawdust is considered to be waste and its disposal must conform to the environmental standards that result from their implementation. The pertinent Spanish laws have established the need to lay down a suitable strategy for the characterization and assessment of sawdust products for the purpose of their satisfactory integration into the dimension stone productive chain. This paper presents the results of a comprehensive characterization study of the granite sawdust of O Porriño (Pontevedra, NW Spain), including a description of its physicochemical, mineralogical and geotechnical properties. On the basis of the results of this characterization, we raise the question of the suitability of this material for use in earthworks as well as in the construction of layers for landfill sealing and/or waterproofing. Our findings show that the properties of granite sawdust are suitable for such purposes, and other possible uses are being studied in continuing research.