Authord by the Institute for Science and International Safety (view PDF)

On July 13, President Trump made it clear that the nuclear-related Pickaxe mountain facility is on the U.S. target list. In an interview on the Hugh Hewitt show, the President stated, “We have eyes on it and Pickaxe mountain is a possible target for a nice big fat shot right in the front door…We’re watching Pickaxe Mountain very closely. We don’t see any activity there.” Trump finished the interview with a more definitive statement: “We're going to take out Pickaxe Mountain. Tell the Iranians to be ​ready.” The tunnel facility under construction has not been previously targeted in either June 2025 or 2026 war, aside from the destruction of a vehicle on a nearby spoil pile, which we believe was most likely associated with air defense.  Our assessment of satellite imagery to date is that the facility is not yet operational, but construction continues.

This nuclear-related site is south of the Natanz enrichment plant, part of a large perimeter secured site that includes another, smaller tunnel complex, initially built in 2007, which was expanded and hardened in recent years and sealed shortly after the June 2025 war. 

The large mountain harboring the main tunnel complex is called Kuh-e Kolang Gaz La, where Kolang translates to Pickaxe, resulting in today’s nickname of the site.  Construction of the Pickaxe mountain facility started in the fall of 2020, and at the time Iran announced that the underground halls were intended to replace the destroyed above-ground advanced centrifuge assembly facility at the main Natanz site. [1]  The destroyed site was designed to assemble about 6000 advanced centrifuges per year, a large capacity, sized to produce the tens of thousands of advanced centrifuges during and after the phasing out of Joint Comprehensive Plan of Action limits from 2025 through 2030.

The Pickaxe mountain site features two pairs of entrances leading under the ridge of the mountain.  They are assumed to lead to one facility, but this is not guaranteed.  The facility is estimated to be at least 100 meters deep under the mountain.  The mountain has a height of 1608 meters above sea level.  The difference in elevation between the eastern entrance and the mountain ridge is about 145 meters.  The difference in elevation between the western entrance and the ridge is about 100 meters [2].  The difference in elevation between the two sets of entrances of about 50 meters could also indicate that the facility has multiple levels. 

The physical defensive measures consist primarily of a large security perimeter and extensive tunnel entrance hardening.  In 2025, Iran started constructing a double (fence and wall) security perimeter with a patrol route surrounding the entire mountain and adjoining the Natanz Nuclear Complex security perimeter.  All four tunnel entrances are excavated in a channel of rock.  Two of the four tunnel portals feature entrance extensions with subsequent hardening. This includes layers of concrete and earth over the tunnel portal entrances.  Since the wars, Iran partially backfilled the pair of eastern tunnel portal entrances to obstruct ground vehicle access but did not seal them fully as previously noted at the 2007 tunnel, the Esfahan tunnel, or the Fordow underground enrichment plant.

It remains unclear when Pickaxe Mountain could be operational, based only on assessments of satellite imagery.  It is also unclear if Iran still plans on installing a large-scale assembly facility, given the destruction of Iran’s centrifuge program, including Iran’s ability to make centrifuge components needed for an assembly plant.  Nonetheless, if Iran starts to rebuild its centrifuge manufacturing capability, it could plan to install a smaller centrifuge assembly facility in Pickaxe Mountain able to serve a nuclear weapons program.  In addition to the originally planned centrifuge assembly plant, the space available under the mountain could be expected to be large enough to also hold a centrifuge enrichment plant capable of producing weapon-grade uranium.  It is likely large enough to also hold certain nuclear weaponization activities such as making weapon-grade uranium metal and shaping it into nuclear weapon components. 

Any operations inevitably have ties to the outside, including via imported equipment, power supply, ventilation, heating, cooling, construction personnel, operating personnel, and deliveries.  All of these connections to the outside present vulnerabilities that the U.S. and Israel would seem to be able to exploit.

The site, in its present condition, would be more suitable for ground forces to attack or sabotage like the destruction of the advanced centrifuge assembly center, which reportedly involved explosives that were brought into the facility during its construction.

However, vulnerabilities may also exist that can be exploited by deep earth penetrating weapons via aerial attacks.  These would be best identified in facility schematics. Schematics for the Pickaxe Mountain facility have not been seen publicly, however, schematics for two other prominent Iranian nuclear tunnel sites, Fordow and Shahid Boroujerdi, have been. These are two tunnel facilities built by Iran’s Amad nuclear weapons program and attacked in June 2025 and March 2026, respectively; both schematics showed ventilation shafts, and both facilities had ventilation shafts directly targeted in aerial attacks, a weak point that allowed greater internal access for earth penetrating weapons. 

In line with the attacks on these two sites, an attack on Pickaxe Mountain could target the above ground incoming power supply lines, the location of ventilation shaft(s) or equipment, and the open tunnel entrances.  The latest imagery from July 9, 2026, shows that the pair of western tunnel entrances remain open, leaving them vulnerable to both precision strike weapons or a ground operation entering the facility via those tunnels.  Air defenses appear easily overcome as was shown by Israel’s very early attacks on the Natanz enrichment complex in June 2025 and two separate attacks in March-April 2025.  Airstrikes targeting solely the hardened tunnel portal entrances, without shockwaves or blast impact affecting the facility, would likely only temporarily deny Iran access and would add Pickaxe mountain to the list of facilities to be watched closely for Iranian attempts to regain access.   

Figure 1 below shows an overview of the site. Figure 2 shows potential ventilation shaft locations. Figure 3 shows the probable ventilation shaft near the Eastern set of tunnel entrances under construction in 2024. 

Figure 1.  A June 30, 2026, Vantor Technologies image overview of Pickaxe Mountain

Figure 2.  A June 30, 2026, Vantor Technologies image of Pickaxe Mountain showing potential locations for ventilation shafts.  The one near the eastern tunnel entrance can be considered a “probable” location given the construction identified in 2024 and shown in Figure 3 below. 

Figure 3.  The probable ventilation shaft near the eastern tunnel entrances under construction in 2024.  Power is supplied to this location via an above-ground powerline that turns into a buried powerline. 

[1] David Albright, Sarah Burkhard, and Frank Pabian, “Looking for Evidence of the Construction of Iran’s New Centrifuge Assembly Plant,” Institute for Science and International Security, October 7, 2020, https://isis-online.org/isis-reports/looking-for-evidence-of-the-construction-of-irans-new-centrifuge-assembly. ; David Albright, Sarah Burkhard, and Frank Pabian, “Update on New Construction Activity at Natanz,”  Institute for Science and International Security, October 30, 2020, https://isis-online.org/isis-reports/update-on-new-construction-activity-at-natanz.