TEHRAN, September 10, 2026 — AALIMI NATION EXCLUSIVE: Construction and reinforcement activity at Iran’s heavily fortified underground complex beneath Mount Kolang, also known as Pickaxe Mountain, has accelerated sharply in 2026, according to a new analysis of satellite imagery by the Washington-based Center for Strategic and International Studies (CSIS).
The latest imagery, including photographs captured on August 9, 2026, indicates that activity at the site this year has reached its highest level since construction began, with extensive work visible around tunnel entrances, internal roads and areas associated with the removal and redistribution of excavated material.
The CSIS assessment, based on imagery covering roughly six years, suggests the project may be moving beyond its earlier excavation phase toward internal construction, while work continues to reinforce the complex's external infrastructure.
The development is significant because of the site's location and design. Mount Kolang, known in Persian as Kuh-e Kolang Gaz La, lies approximately two kilometres south of Iran's Natanz uranium-enrichment complex and is buried beneath a granite mountain, providing the facility with substantial natural protection.
Activity Intensifies in 2026
Satellite imagery examined by CSIS shows a marked increase in construction activity during the current year.
Researchers identified reinforcement and extension work around tunnel portals, improvements and paving along internal access roads, increased movement of construction vehicles and continued handling of material believed to have been excavated from underground sections of the facility.
The changes indicate that the site has developed considerably from its earlier construction stages, with more substantial access, security and support infrastructure now visible around the complex.
However, the imagery does not reveal what is inside the mountain.
CSIS cautions that satellite imagery alone cannot establish whether centrifuges, enriched uranium or other nuclear equipment have been installed underground. There is consequently no independent confirmation from the imagery that uranium enrichment is currently taking place at Mount Kolang.
Why Pickaxe Mountain Matters
Iran announced plans for a new underground centrifuge-related facility near Natanz in 2020, following a fire that damaged an above-ground centrifuge assembly workshop at the Natanz complex.
The decision to move sensitive infrastructure underground was widely viewed as an effort to provide greater protection against potential military strikes.
The physical characteristics of Mount Kolang make the site particularly difficult to target. Much of the complex is believed to be located deep beneath a mountain, leading analysts to assess that conventional attacks could potentially damage or delay the project without necessarily destroying its deepest sections.
The facility also drew attention during the US strikes on Iran's nuclear infrastructure in June, when, according to CSIS analysis, Mount Kolang was not among the underground sites targeted.
Construction activity at the complex subsequently continued.
IAEA Seeks Access
The International Atomic Energy Agency (IAEA) has sought information from Tehran about the facility and requested access to establish its purpose and status.
Iran has not provided the requested access, according to the CSIS assessment.
That lack of direct inspection has left the international community unable to independently determine what activities, if any, are currently taking place inside the mountain.
The dispute forms part of a broader deterioration in the IAEA's ability to conduct verification work in Iran following the military confrontation and restrictions imposed on the agency's activities.
Trump Again Raises Prospect of Military Action
The latest satellite findings emerge as tensions between Washington and Tehran remain high.
US President Donald Trump has repeatedly warned that the United States could target Pickaxe Mountain if Iran continues activity that Washington considers threatening.
On September 10, Trump again warned Tehran over what he described as provocative activity at the site and indicated that military action remained a possibility.
The comments underscore the strategic importance Washington attaches to the facility as the United States seeks to prevent Iran from rebuilding sensitive nuclear infrastructure.
But Mount Kolang presents a particularly difficult military target.
Its depth, hardened construction and location beneath a mountain have raised questions among analysts over whether even the most powerful conventional bunker-penetrating weapons could completely destroy the facility's deepest underground sections.
Construction Does Not Mean Enrichment
The latest satellite imagery provides compelling evidence that construction and reinforcement activity has accelerated significantly at Mount Kolang during 2026.
It does not, however, establish that the complex is operating as a uranium-enrichment facility.
That distinction is critical.
The site's proximity to Natanz, its deeply buried architecture and its association with Iran's plans for protected centrifuge infrastructure make it a major intelligence concern. Yet without physical access to the facility, its precise internal configuration, equipment and operational status remain uncertain.
The acceleration in construction nonetheless adds another potentially dangerous dimension to the confrontation between Iran and the United States.
As Washington considers its military options and the IAEA continues to seek greater access, Mount Kolang is increasingly emerging as one of the most sensitive and difficult-to-resolve elements of Iran's nuclear dispute.
For Iran, the underground complex offers protection for potentially sensitive infrastructure. For the United States and its allies, its continued development raises questions about whether Tehran is rebuilding capabilities that could survive future military strikes.
The answer may ultimately depend on what lies beneath the mountain something satellite imagery alone cannot yet reveal.
AALIMI NATION will continue to monitor developments surrounding Iran's nuclear programme, the IAEA's verification efforts and the escalating confrontation between Tehran and Washington.
