Extractive waste management: a new territorial and industrial approach in Carrara quarry basin

Abstract

Raw Materials, whose availability is increasingly under pressure, are essential for the EU economy: Europe is strongly interested in “resource preservation” and, furthermore, several researches are focused on the recovering of Critical Raw Materials and aggregate supply from landfill (“waste recycling”). On the other hand, quarry waste represents an enormous loss of resources and causes economic and environmental cost increase due to waste management and landfill activities. A significant part of quarry waste is valuable, but often lost because of not efficient recovery practices (unclear legislation and general lack of data hamper). In 2014 the mining and quarry industry represented the second most important sector (after C&DW) in terms of waste quantities produced in the EU-27 (28.1% or 703 milion tons: Eurostat, 2017). A great deal of waste can be regained as valuable raw materials by the enhancing of quarry waste recovery processes to obtain Secondary Raw Materials (industrial minerals, aggregates, etc.). In Italy large amounts of quarry waste have been and still are dumped. Such materials can represent a great alternative resource for Secondary Raw Material exploitation. Several dimension stone quarries, both from carbonate and silicate rocks, are interested by quarry waste exploitation: a noticeable example is the potential exploitation Carrara marble waste. The Carrara quarry basin is represented by one hundred quarries for colored and white marble exploitation. The waste production can be summarized in: 80 Mm3 waste present in old quarry dumps (Ravaneti) and 3 Mm3/y of waste from quarrying activities. At present only 0.5 Mm3/y of quarry waste is exploited for Secondary Raw Material production. On the basis of the grain size and chemical characteristics, several applications as SRM are possible: e.g. asphalt, cement, plaster, rubber, sealants, paper, paint, plastic, etc.... Other potential applications as by-products are: aggregate for concrete and crushed materials for embankments and armour stones. Moreover, the big chance for the future – in order to solve also hydrogeological and stability problems in the Carrara Basin - is treating “poor” material (called terre) to new, performing markets. A preliminary research about Carrara Marble EW recovery was set up: two areas were sampled (Calocara and Lorano) and the sampled materials were analyzed to get information about size distribution, density, Atterberg limits, Los Angeles test, freezing and heat tests, flat and shape indexes, geochemistry, mineralogy. The first (preliminary) results shows a good attitude for quarry waste to be recovered. The present research will show the state of the art and the potentiality of quarry waste exploitation in Carrara, highlighting best practices and efficient recovery processes (technologies and techniques).