The manufactured shaft is located in a garden adjacent to the Piazza Celimontana with a circular diameter of 34.80 meters. The Iron Floor is at a depth of -15.50 metres below sea level resulting in a significant excavation depth of the structure of approximately 59 metres from street level. The structure consists of 6 horizontal elements:
- A technical floor at a height of 27.18 metres above sea level (finished)
- A technical floor at a height of 20.55 metres above sea level (finished)
- An intermediate floor at a height of 11.60 metres above sea level (finished)
- An intermediate floor at a height of 3.35 metres above sea level (finished)
- An intermediate floor at -4.90 metres below sea level (finished)
- A platform floor at -14.46 metres below sea level (finished), with the Iron Floor at -15.50 metres below sea level.
The excavation of the structure was carried out following the construction of reinforced concrete bulkheads and excavated with a hydraulic excavator. The excavation technique and construction of the shaft is of the “down-up” type. During the downward excavation of the shaft, only the round circular beams were designed in correspondence to the various horizontal sections, while the inter reinforced concrete walls subsequently provided the structures for supporting the horizontal elements on the way up.
Based on recommendations from the Archaeological Superintendence, the construction of the excavations up to the levels involved in Archaeological surveys (19 metres above sea level) have been carried out in an archaeological way that provides for subsequent horizontal layers.
The presence of reinforced concrete bulkheads allowed the safe descent of the archaeological excavations to a depth otherwise unreachable.
At a depth of about 17 metres from contemporary street level an aqueduct from the Republican era emerged, in squared blocks of tufa, connected to a large basin dating back to the third century B.C. A vault was also found with objects dating from the end of the X to the beginning of the IX century B.C.