Satellite images captured and analyzed by the Center for Strategic and International Studies (CSIS) showed a strong uptick in construction activity at Iran’s Pickaxe Mountain fortress (Pickaxe, in a literal translation). This could corroborate the suspicion that the site has been prepared in recent years to become a future uranium enrichment facility or a secure nuclear shelter for the country.
These new strategic insights explain why, last week, President Donald Trump told reporters that the United States could strike Pickaxe Mountain very soon.
Read also: Iran denies nuclear activity on the mountain and accuses the U.S. of creating a pretext for attacks
In July, Israeli intelligence said it believed Iran had transferred thousands of nuclear centrifuges to deep tunnels inside the mountain, where there is a fortified underground installation near Natanz, according to a Wall Street Journal report.
The assessment stated that the centrifuges could be used to enrich the stockpile of 440 kilograms of uranium enriched to 60% for weapon-grade material and potential use in nuclear warheads.
The InfoMoney gathered information on Pickaxe Mountain to gauge the risks of such a facility and the difficulties for the United States to take steps to interrupt the possible military use of the installation. See below;
What is Pickaxe Mountain?
Pickaxe is a mountain in the Zagros range, in Isfahan Province, Iran, located nearly 1.5 kilometers south of the Natanz enrichment complex. According to news agencies, the Western name is a small translation mishap. The mountain is called Kuh-e Kolang Gaz La in Farsi — kolang means pickaxe. But Iran would never have publicly named the site.
The facility is a large complex of underground tunnels built about 100 meters below the surface and began construction in 2020, months after an explosion destroyed an above-ground advanced centrifuge assembly factory at Natanz in an attack attributed to Israel. The site was chosen precisely because the mountain is composed of hard, dense granite, which provides substantial natural protection for anything excavated beneath it.
The destroyed plant had been built to assemble around 6,000 advanced centrifuges per year.
What does Iran keep at the site?
The answer is: no one knows. The International Atomic Energy Agency (IAEA) has never had access to the site. There is a double security perimeter, a fence and a wall with patrol routes surrounding the entire mountain, which join the Natanz perimeter. Satellite imagery shows that there are two tunnel entrances, one on the east side and another on the west side.
Iran stated that the site is for the production and assembly of advanced centrifuges, but analyses indicate that the space beneath the mountain is large enough to house not only an assembly factory but a functional enrichment plant capable of producing weapon-grade uranium and even a uranium metal foundry, to be molded into weapon components.
And Israeli intelligence states that the 440 kilograms of Uranium enriched by Iran would have already been transferred to the facility.
Read also: Iran says it will not give up uranium enrichment and pressures negotiations with the U.S.
Is the facility active?
According to CSIS analysis, Iran continued construction activities at Pickaxe Mountain after Operation Midnight Hammer in June 2025. Between June and September 2025, Iran completed the security perimeter around the entire installation, reinforced and expanded several tunnel entrances with portal doors, and accelerated the pace of excavations at the facility.
Satellite monitoring since 2020 reveals a clear tri-phasic activity signature at the five main points of interest, as well as the roads that connect them. The time-lapse image comparisons show that new activities have been occurring.
The entrances to the south and east portals are more reinforced in July 2026 than in September 2025. According to CSIS, there is evidence across the site of removal of excavation deterioration, which is typical of a construction site transitioning from the cut phase to the building phase and is a likely indication that construction has shifted to the internal construction of the underground facility.
Can the site be attacked?
Strategy experts consider it very difficult to damage a facility buried beneath 100 meters of granite. The GBU-57, the United States’ largest bunker-busting bomb, can penetrate 18 meters of concrete or 61 meters of earth.
Satellite images show that the tunnel portal entrances at Pickaxe are curved in a U-shape, which could prevent missiles from flying straight through the tunnel corridor and reduce the shock waves created by explosions that channel energy to the underground installation.
An analysis by the Institute for Science and Global Security notes that even a buried facility still needs to breathe, that is, the operating complex requires power, ventilation, heating and cooling, deliveries, and people coming and going, and this would be a vulnerability to be exploited in an eventual attack.
Other underground sites built by Iran’s nuclear program at Amad, Fordow and Shahid Boroujerdi had ventilation ducts and were targeted by airstrikes in June 2025 and March 2026. Thus, an attack would likely target the ventilation ducts and the open tunnel mouths of Pickaxe.
The Pentagon may then decide that a more effective strike on Pickaxe Mountain involves targeting and destroying tunnel entrances with cruise missiles, rather than attempting to cause structural damage to the underground installation itself.
Another option would be to carry out attacks or sabotage by ground forces, a strategy that worked at Natanz in 2020, when explosives were reportedly brought inside the building during its construction.
What does Iran say?
The Iranian government has insisted that there is nothing to bombard at the site. The spokesperson for the foreign ministry, Esmail Baghaei, said in July that “no nuclear activity is taking place” on the mountain and called the U.S. threats a “fabricated pretext for aggression, destruction and sabotage.”
But Mehdi Mohammadi, an adviser to the president of the parliament, called Pickaxe Mountain “the most fortified nuclear facility in the world” and said that an attack “would turn the region into hell.”
Meanwhile, Iran’s Joint Military Command warned that any attack on nuclear or sensitive sites would widen the war.
