ABSTRACT:

In the Campiglia area (Southern Tuscany – Italy) a large quarry district is active near inhabited areas and a Natural Regional Park. Specific attention is given to an ancient castle (Rocca San Silvestro), frequently visited by tourists, positioned at close distance from the quarries (<1000 m), both for the castle stability and for the visitors safety. Monitoring of seismo-acoustic waves was done with a seismo-acoustic array, that allowed to identify signals produced by mining activities from the back-ground signal. The infrasound array analysis provided in real-time the peak amplitude of seismic ground shaking and the excess pressure for blasting from all the quarries active in the area and located at distances ranging form 1000 to 4500 meters from the array, thus representing an efficient real-time monitoring tool for quarry districts.

1 FOREGROUND
1.1 Quarrying activity

In the Campiglia area, (Tuscany-Italy), there are very large outcrops of carbonate platform massive limestone (Calcare Massiccio Frt.) partially interested by a slight contact metamorphism resulting into marble formation and ore deposits with skarn of mixed sulfurs (Tanelli, 1983). This setting drove to establish mining activity in the Etruscan, medieval and XIX-XX century time. At present all mines are disused but recovered as a Mining Park in the frame of the Regional San Silvestro Mining Park (http://www.parchivaldicornia.it/parco.php?lang=eng&code=000&code=ssil-gen). In the last decades of the XX century four large open-pit quarries were opened in the area (Fig. 1) in order to quarry limestone for soda industrial process, steel-plant and civil engineer purpose. Quarrying is made by drill and blast with each blasting of about 2,000m3 (≈5 kt). 1.2 Monitoring In order to reconcile both the social and economical aspects, in agreement with the Park authorities it was established to run an adequate environmental monitoring.

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