KABUL, Afghanistan — Afghanistan is gearing up to award contracts to mine one of the world’s largest iron ore deposits, the country’s top mining official said Thursday. The ore is buried in a peaceful province of the nation, which officials believe has at least $3 trillion in untapped minerals.

Geologists have known for decades about Afghanistan’s vast deposits of iron, copper, cobalt, gold and other prized minerals, but a U.S. Department of Defense briefing earlier this week put a startling price tag of nearly $1 trillion on the reserves.

Afghanistan’s Minister of Mines Wahidullah Shahrani called that a conservative estimate. He said he’s seen geological assessments and industry reports estimating the nation’s mineral wealth at $3 trillion or more.

For Afghanistan, a war-torn, landlocked country with virtually no exports, it is a potential windfall, although formidable obstacles remain, including lack of investment, infrastructure and adequate security in most of the nation.

“The ministry has been working closely with the international organizations, including the World Bank, the U.S. Geological Survey and the international mining and finance community for some time to ensure all of the Afghan people benefit from our rich natural resources for decades to come,” said Shahrani.

Shahrani plans to travel to Britain next week to present 200 foreign businessmen with information about the estimated 2 billion tons of iron ore at Hajigak in Bamiyan province, where the Taliban and other insurgents have no significant presence. The project is to be bid on this fall with contracts awarded late this year or early next year, he said.

Critics of the war in Afghanistan have been skeptical that the estimates were timed to spur foreign governments to support the war effort.

But Shahrani insisted that the release of the information followed months of work to assess the mineral deposits.