The Grotta della Monaca is a natural cavity which opens in the dolomitic limestone of the Trias. It is formed by three separate morphological macro-sectors: a large entrance corridor (3-4m high) with klastic deposits on the floor; a vast central cavern (the so-called “Hall of the Bats”, 60x30m, 6m high) which slopes down towards the rear of the cafe; a series of long, narrow terminal cunicoli, impassable by man. In 2005, the investigationsl, underway since 2000, concentrated in two sectors in front of the cave, at the entrance, denominated “S6” and “m0”. The first uncovered an extensive ledge for mineral extraction adhering to the left hand rock face. The marks made by metal picks, visible on the residual mineral deposit of iron (goethite), attest extraction activity in the post-medieval period. An occupation level was reached, which the pottery finds date to the middle Bronze Age. The typology of vases found, the faunal remains (_ovis vel capra_) and the condition of the sedimentary deposits (presence of so-called “cake deposits”) suggest that this place was used for stabling animals. The presence of handmade pottery decorated with red bands confirmed the Neolithic occupation. In the same area, in front of the entrance, a small underground conduit, “m0”, was explored. This was a small secondary offshoot positioned on the right of the main corridor of the underground system and Eneolithic pottery, grindstones, punches and spatulas were found here. Several exploratory soundings were made into the hall of the “Terminal cuniculi”, in the deepest part of the cavern. The pottery recovered indicates a dating horizon between the early Eneolithic and the middle Bronze Age. (MiBAC)

During the 2009 field season, excavations and photographic documentation were carried out of the deepest sector of the cave (Cunicoli Terminali), where during the 2008 season a new burial area had previously been discovered. The excavations brought to light numerous human skeletons, including many young children. At the same time, the excavations of the underground areas where mining took place were extended, and a careful sampling taken of the charcoal remains (parts of torches for the illumination of the subterranean areas). Remaining in the context of the evidence for mining, we should note the recovery of additional lithic tools for digging operations (hammers and mallets). These tools were retrieved from the clastic fills investigated up to a depth of three metres from the surface; their position in the debris highlights the enormous earth removing operations carried out by the prehistoric miners. A series of radiocarbon dates has allowed the identification of three distinct phases of ancient human activity in the subterranean site: the earliest dates to around 20000 years ago (radiocarbon dating of a sample from a human ulna); the next phase placeable between 6500 and 5500 years ago (six measurements from charcoal and bone remains); and the most recent between 1250 and 1400 AD (two measurements from charcoal).

The three research and excavation campaigns took place in the months of April-May, June and October, each lasting 10-15 days. The investigations concentrated on the underground macro-sectors in the Sala dei Pipistrelli (April-May), the Cunicoli Terminali (June) and the Pregrotta (October) and involved teams of 8-10 speleologists and archaeologists, apart from in the Sala dei Pipistrelli where, due to the difficult environmental conditions, only two people could work. In the area of the Cunicoli Terminali excavations took place in three different underground zones (Cengia, Salto and Imbocco CTdx). These interventions, aimed to gain a better understanding of the ancient quarrying processes in the deepest part of the grotto, led to the removal of substantial sedimentary and/or clastic deposits. These deposits were carefully investigated as they incorporated a myriad of miniscule charcoal fragments, the residue from the ancient lighting systems used below ground (torches made from resinous wood). Subsequently, the carefully collected anthracological samples were used for a series of archaeo-botanical analyses and diverse radiocarbon datings. The latter once again confirmed the chronological horizon for the mining activities attested in the innermost part of the cavern (Sala dei Pipistrelli and Cunicoli terminali), as datable to the end of the 5th-mid 4th millennium B.C. (in calibrated chronology). In the Sala dei Pipistrelli the exploration of the so-called Buca delle Impronte continued. This is a secondary branch characterised by evidence of mining that is exceptionally well- preserved despite its antiquity (quarrying marks, pillars for sustaining the vault etc.) The investigation identified the busiest crossing points on the paths used by the ancient miners, characterised by the presence of heavily compacted surfaces which originated from the constant coming and going during the mining activity. The context dates to a late phase of the Neolithic period, around about the beginning of the 4th millennium B.C. Lastly, the excavation in Pregrotta explored the last part of the deposit still preserved next to the ample entrance to the cavity (Trench S9). The stratigraphic excavation once again revealed the damage caused by late medieval and post-medieval mining to the much earlier occupation evidence on the site, in particular that relating to the prehistoric and proto-historic periods. Digging was undertaken in order to exploit the deposits of ferrous hydroxides existing below the prehistoric and proto-historic occupation levels causing damage to the existing stratigraphic sequences in the Pregrotta. The damage was attested by metal pick marks at a substantial depth in the sedimentary deposit as well as “reverse stratigraphy”, with ancient materials present above later evidence, due to the action of the later miners. To date three distinct phases of ancient anthropological activity have been defined for the underground site: the earliest is datable to around 20,000 years ago (Pregrotta); the middle phase dates to between 6,500 and 5,500 years ago (Sala dei Pipistrelli and Cunicoli terminali); the latest phase can be dated to between 900 and 1400 B.C. (Pregrotta and Cunicoli terminali).