Washington D.C. – Web Desk: Iran’s underground nuclear facility at Kuh-e Kolang (Pickaxe Mountain) represents a significant strategic challenge for the United States, as the site is buried deep within a mountain in the Zagros range, potentially beyond the reach of America’s most powerful conventional bunker-buster bombs .
Located near the Natanz uranium enrichment complex in central Iran, the facility is believed to be Iran’s most heavily fortified nuclear site . Construction began in 2020 after Iran attributed a sabotage incident at Natanz to outside forces .
A Fortress Under the Mountain
The facility is buried at least 328 feet (100 meters) deep inside a granite mountain, significantly deeper than the Fordow facility, which sits at approximately 80-90 meters depth . The site features two pairs of tunnel entrances leading to large underground halls believed to be capable of housing centrifuge assembly or enrichment operations .
Granite offers far greater compressive strength than the sedimentary rock above Fordow, making the site inherently more resistant to conventional strikes . Iran has also reinforced tunnel entrances with concrete and protective overburden, and partially backfilled some portals to block rapid vehicle access .
The Bombs vs. The Mountain
The largest conventional bunker-buster bomb in the US arsenal, the GBU-57/B Massive Ordnance Penetrator (MOP), is capable of penetrating approximately 200 feet (61 meters) of soil and concrete before detonation . This appears insufficient to reach the main halls of the Pickaxe Mountain facility .
Multiple bombs could be dropped on the same impact point in a “drilling” approach, as was done during Operation Midnight Hammer strikes on Fordow in June 2025 . However, experts suggest even this method may not guarantee destruction of the deeply buried halls . Potential alternative options include targeting tunnel entrances, ventilation shafts, or power and ventilation infrastructure to disable the facility, rather than attempting complete destruction .
Uncertain Activities, Limited Access
The International Atomic Energy Agency (IAEA) has not been granted access to the site, making it a “blind spot” for international oversight . Iran has stated the facility is intended to produce centrifuges, but it could potentially be repurposed for uranium enrichment or other nuclear activities . Satellite imagery shows ongoing construction and vehicle movement at the site
