New satellite imagery appears to show Iran taking additional protective measures around a deeply buried underground facility near its main nuclear infrastructure at Natanz Nuclear Facility, according to a new assessment by the Washington-based Institute for Science and International Security.
The institute said imagery of the underground Pickaxe Mountain complex — also known as Mount Kolang Gaz La — suggested that by late April, Iran had partially blocked two eastern tunnel entrances using large amounts of grey earthen material.
Analysts said the material appears designed to slow or prevent rapid vehicle access into the tunnels.
Earlier satellite imagery taken on April 1 showed the entrances fully open and unobstructed. By April 22, however, the institute said noticeable changes could be seen at the site.
“Based upon newly available satellite imagery of the Pickaxe Mountain underground complex, just south of the Natanz Nuclear Complex, it appears that as early as April 22nd, the two eastern tunnel portals have been partially blocked by grey earthen material used to prevent vehicle access,” the institute said in its assessment.
While the entrances have not been fully buried or concealed, analysts noted the barriers would still significantly complicate movement in and out of the tunnels.
The institute said the obstructions “would appear to be sufficient to significantly hinder rapid ingress/egress by vehicles and would require the use of heavy earth moving equipment to gain such access and clear an unobstructed path inside.”
Unlike measures previously observed at tunnel systems linked to the Fordow Fuel Enrichment Plant and facilities near Isfahan, the new activity at Pickaxe Mountain does not completely hide the tunnel portals from view.
Still, the development has drawn attention because of the location and depth of the complex.
The institute said the activity raises “significant questions” given that the underground site could potentially be used to shelter sensitive equipment, nuclear-related materials or other strategic assets from airstrikes or surveillance.
Analysts also pointed to earlier activity at the mountain involving older tunnel systems dating back to 2007.
According to the report, those older portals had previously been buried and reinforced with concrete — a move that researchers said may indicate material or equipment had already been relocated deeper into the mountain.
“To note, earlier in the year, we observed how the old tunnel portals to a complex dating back to 2007 at Pickaxe Mountain were buried and hardened with concrete, which suggests that something may have been moved into those tunnels,” the institute said.
The report added that there is currently no visible sign that similar barriers have yet been placed at the site’s two western tunnel entrances.
The underground Pickaxe Mountain complex has long drawn international scrutiny because of its proximity to Natanz, Iran’s main uranium enrichment site, and because facilities built deep inside mountains are generally considered more resistant to conventional military strikes.
