Since 2004 the School of Medieval Archaeology at Siena University has been carrying out an archaeological survey on the territory of Monterotondo Marittimo. The aim is to define the diachronic settlement tendencies and at the same time clarify the role played by the exploitation of the natural resources present in the area, in particular those below ground. In fact, the territory in question is rich in mixed sulphates and alunite. In the area of Monteleo-Macchia dei Burelli in particular, topographical analyses identified substantial evidence for the production of alum, known from documents from the 18th century onwards. More specifically, quarry faces, bore holes and tunnels still usable in part were found. Close to the quarry three distinct sets of ovens with different structures were identified. Over all the site, where the Lorraine Regency made conspicuous investments from the mid 18th century, which was not touched after the cessation of production activities which functioned between 1741 and 1753, is of unique importance for the study of the techniques for producing alum from alunite in the pre-industrial period. Moreover, the historical documentation is greatly advantaged by the fact that in 1745 Monteleo was visited by Giovanni Targioni Tozzetti, who stayed there for seven days observing the work of the “alluminotti” and wrote detailed descriptions of his findings for the Count of Richecourt.

During September-October 2008 the department of Archaeology and History of Art began the first excavations of the complex. The aim was to define its layout and, in particular, study two of the four ovens near the large quarry of Buca dei Falchi. Overall the ovens were in a good state of preservation and showed the traces of numerous repairs connected with the firing phases. As well as permitting a correct reading of the functioning of these structures within the alum production cycle, the data which emerged at the end of the investigation also led to the hypothesis that the first phase of use of the alum mine at Monteleo dated back to at least the 16th century, that is the period of the first great resumption of Tuscan alum production following the fall of Constantinople in 1453.