Iran's 100-Yard-Deep Pickaxe Mountain Tunnels: A New Space-Based ISR Priority

When a nuclear site is carved 100 yards below solid rock, it becomes invisible to most airborne sensors and impervious to all but the heaviest conventional bombs. That reality is reshaping how the space and missile defense communities think about counter-proliferation. Pickaxe Mountain’s depth makes it a compelling test case for next-generation space-based radar, hyperspectral imaging, and ground-motion monitoring—capabilities that may soon be the only way to detect enrichment operations that even the IAEA cannot inspect.

Israeli intelligence has concluded that Iran moved thousands of uranium-enrichment centrifuges into deeply buried tunnels inside Pickaxe Mountain last fall, according to officials cited by The Wall Street Journal. The transfer, which occurred after the 12-day June 2025 war that saw American and Israeli strikes pummel Iran’s three main nuclear sites, represents a significant, covert shift in Tehran’s nuclear infrastructure. The mountain—known locally as Mount Kolang—lies roughly 2 kilometers south of the Natanz enrichment complex, which was itself attacked during the US military operations that began on February 28, 2026. While Pickaxe Mountain was not a primary target in either the 2025 war or the subsequent 2026 strikes, its use as a fallback storage and potential production site for centrifuges has long been a high-priority concern for both US and Israeli intelligence.

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Israeli intelligence has concluded that Iran moved thousands of uranium-enrichment centrifuges into deeply buried tunnels inside Pickaxe Mountain last fall, according to officials cited by The Wall Street Journal.

Satellite imagery and intelligence reports paint a picture of a heavily fortified, deeply buried facility. The tunnels have been carved more than 100 yards below bedrock, making the complex deeper and more hardened than Fordow, Iran’s other underground enrichment site. Open-source analysts at the Institute for Science and International Security (ISIS) have tracked consistent activity at the site over the past 15 months, including truck traffic, tunnel reinforcement, and the construction of a security perimeter. Crucially, Iran has denied International Atomic Energy Agency (IAEA) inspectors access to the mountain, claiming the site is intended solely as a factory for producing and assembling centrifuges—not as an active enrichment facility. IAEA Director General Rafael Grossi has publicly demanded that Iran provide answers about its activities there, but as of the reporting, no inspections have taken place.

The presence of centrifuges inside these tunnels does not automatically mean Iran has begun enrichment operations at Pickaxe Mountain. Following the extensive damage to Natanz’s above-ground facility—the IAEA confirmed its destruction—and the likely severe damage to the underground enrichment halls, Tehran may have moved surviving centrifuge components to the mountain simply to consolidate and protect its remaining uranium-enrichment capability. However, the scale of the transfer—described as thousands of centrifuges—and the persistent construction activity raise the possibility that Iran could eventually use the site to reconstitute a clandestine enrichment capability. The depth and hardness of the tunnels would make it extremely difficult to destroy the centrifuges with conventional air-delivered munitions, potentially requiring the use of massive ordnance penetrators or even tactical nuclear earth penetrators, which in turn would dramatically escalate any military confrontation.