For him and for those familiar with the mine's operations, as well as for the community of Lula, Sos Enattos is a sacred place. Former director Luca Loddo stated this publicly to the scientists who lead the research institutions involved in the international Einstein Telescope project, such as the National Institute of Nuclear Physics, the Institute of Geophysics and Volcanology, and the National Institute of Astrophysics. He admitted his emotion, speaking of the "second life of this small and precious mine," flanked by the Minister for Universities and Research, Anna Maria Bernini, and the President of the Region, Alessandra Todde, during the visit to Sos Enattos by the Minister of Saxony, Sebastian Gemkow, to seal the Italian-German alliance, which in the race for ET is proposing the double-L model, supported by over 200 scientists. It envisions the construction of a plant in Lula and another in Lusatia, a region of Saxony.
Loddo is at home at Sos Enattos: he's worked there for nearly forty years and witnessed firsthand the changes, the crises, the closure, and even the idea of reusing this site for scientific purposes, particularly valuable for its profound silence, a virtue researchers discovered after probing many other places around the world. He's the first to answer the phone call announcing the ET, even though nothing is yet known about the mega-international project to study gravitational waves.
"In the summer of 2010, I received a call from Professor Fulvio Ricci of the National Institute of Nuclear Physics, Rome's La Sapienza branch. He was looking for a mine at least 100 meters deep to study its silence. The next day, he came to the mine and told me about the upcoming Einstein Telescope project. I was hesitant because at the time, they were looking for the ideal site for the nuclear waste disposal site," recalls Loddo, then director of the mine.
"The other Sardinian mines we contacted rejected the request. I accepted out of curiosity; I was thinking of a circular economy. We had mine parts available for this purpose. After the first ten days of instrumental monitoring, the researchers discovered that it had the right characteristics. They also had a team of future competitors in the race to build the infrastructure: the Dutch," adds Loddo, recalling that turning point for a mine that no longer produces extracted material, but becomes a historic site of cultural identity to be offered to visitors.
"We built the first permanent measurement stations, wiring the mine with kilometers of fiber optics and internet connections to have all the data collected in real time at research centers around the world," he recalls. He continues: "Years later, we obtained the first funding to build the SAR Grav laboratories used for various fundamental physics experiments, such as the Archimedes project, a large, highly sensitive scale designed to weigh vacuum. It has a diameter and height of 3 meters and weighs 25 tons."
The mine thus changed its appearance. It ceased to be the mining site that Loddo had known in decades past: "We first excavated it, especially the modern section, to exploit the Tupeddu vein that had been 'lost' by the mine's previous owners and to continue extracting the minerals from a truck-accessible ramp, no longer from the distant Rolandi shaft with one-cubic-meter wagons. The mine wasn't very pleasant in those days; we worked in the mud in rubber boots, with the air filled with diesel engine fumes, explosives, and the deafening noise of the electro-hydraulic drills, wheel loaders, dump trucks, and the constantly running fresh air fans."
Then the closure. "In 1996, a national program shut down Sardinia's metal mines. We insisted on being a worthy part of the nascent Geomineral Park, initially designed for Sulcis Iglesiente only. Sos Enattos, Funtana Raminosa, and Orani each participated with 3 percent."
It was the start of a new phase: "We immediately began cleaning and securing three kilometers of tunnels saved from exploitation, half in the modern section and the other half in the old tunnels served by the Rolandi shaft. We turned them inside out and made them easily accessible to anyone. We also opened them to visitors, and the miners learned to act as guides, sharing their work experiences. To make the operation economically viable, we needed about 100,000 tickets a year, each costing 8 euros. In four years, the tickets only paid for the necessary electricity. Selfishly, however, we had created a fully restored mine museum, both underground and above ground, including a museum, a small restaurant, and a Fioretti washery."
Then came the scientific breakthrough, completely unthinkable. "Thank you for the opportunity you are giving these places, sacred to those who worked there, to those who work there, and to the entire population of Lula. In this important phase of giving this mine a second life, we are confident in a prosperous future for all of Sardinia," former director Loddo told the audience gathered on November 3rd in the mining museum hall to welcome Minister Bernini and the delegation from Saxony. He received applause and expressed the hope that SOS Enattos's candidacy would be successful, along with the Lusatia site.