ByYONAH JEREMY BOB 
Updated: 
High-resolution satellite imagery of Iran’s largest and most crucial remaining nuclear facility shows a recent rush to protect it from potential US or Israeli aerial attack, according to the Institute for Science and International Security (the “good ISIS”).

Satellite imagery on Tuesday appeared to show that Tehran has taken advantage of delays in any such attack since the December 28 protests started to better defend the facility.

The nuclear facility in question is a large tunnel complex at Kuh-e Kolang Gaz La, aka Pickaxe Mountain. It is near a series of Natanz nuclear facilities that were the center of the Islamic Republic’s nuclear program until the 12-day war between Israel and Iran last June.

Most of the other numerous Natanz facilities, including existing centrifuges at the time, were destroyed in the conflict. For reasons that have not been fully explained, this facility was not struck.

Construction at the site started by 2021, and the ISIS think tank and The Jerusalem Post revealed its existence to the public in early 2022.

People wave flags next to an Iranian missile on display during the 46th anniversary of the Islamic Revolution in Tehran, Iran, February 10, 2025. (credit: MAJID ASGARIPOUR/WANA
People wave flags next to an Iranian missile on display during the 46th anniversary of the Islamic Revolution in Tehran, Iran, February 10, 2025. (credit: MAJID ASGARIPOUR/WANA (WEST ASIA NEWS AGENCY) VIA REUTERS)

According to the think tank, the relatively new, enormous underground facility is still not thought to be operational, one of the reasons it may not have been struck previously. But there are concerns that it could be used to enrich uranium or even for some kind of clandestine rush to a small nuclear weapon at some point if not dealt with.

Tehran continues to invest in its most important undamaged nuclear facility

Since last June, it almost certainly has received extra attention and emphasis from Iran as its singularly most important undamaged facility for potential nuclear program use.

From the start, Iran had been digging and building this new facility near the Natanz area very deep under the mountain, which is far larger than the one atop the Fordow facility and would be even more impregnable. The US bombed Fordow with bunker busters last June.

The main mountain harboring the new Natanz tunnel complex is 1,608 meters above sea level, the think tank said.

The mountain that harbored the Fordow centrifuge enrichment plant, called Kūh-e Dāgh Ghū’ī, was about 960 meters tall.

This makes the Natanz mountain about 650 meters taller, or more than 50%, potentially providing even greater protection to any facility built underneath it.

All this was true even before last June.

Heavy construction suggests facility is not yet ready for operations

In a previous report, ISIS president David Albright wrote: “Fordow is already viewed as so deeply buried that it would be difficult to destroy via aerial attack. The new Natanz site may be even harder to destroy.”