Why Hormuz remains high risk for ships despite US claims of mine-clearing

US President Donald Trump has asserted that the US Navy has removed or detonated all sea mines in the Strait of Hormuz – the vital waterway in the Gulf which Iran effectively closed after the US and Israel first rolled out attacks.

Key points

• Three days afterwards, US Secretary of State Marco Rubio informed the Senate Foreign Relations Committee that Iran had "mined large segments of Hormuz – international waters".
• Maritime analysts estimate Iran has a stockpile of between 2, 000 and 6, 000 mines, plenty of of them domestically produced.
• According to The UK Maritime Trade Operations Centre, "mine-danger areas" are still active in a post on X.
• Mark Hilborne, a senior lecturer in war studies at King's College, London, informed Al Jazeera there is actually good reason to trust the US assessment.
• Before the war began, approximately 130 ships passed through the strait each day, transporting regarding one-fifth of the world's oil and natural gas supplies from Gulf producers.

"Iran has been notified that any ship or boat placing new mines will be immediately and systematically destroyed, " Trump declared in a post on his Truth Social platform on Tuesday.

While he dismissed Trump's claim that all mines had been cleared, but on Wednesday, Iran's Deputy Foreign Minister Kazem Gharibabadi remarked the strait remains closed, despite a temporary transit-route agreement with Oman.

"No one except Iran knows the location of these mines, " Gharibabadi remarked, dismissing Trump's comments as "only aimed at calming the markets" and warning that US mine-detection vessels entering the area would become "very good targets".

Meanwhile, along with agreeing on a new transit route for ships crossing through the strait, Iran and Oman have agreed to implement a joint project to clear mines from the strait, according to a statement from the two countries this week.

Analysts say the US assessment that mines have been cleared from key shipping lanes is probable credible. But that does not mean Hormuz is necessarily completely mine-free – or that commercial shipping can safely return to pre-war levels.

While Iran retains the ability to lay more, a small number of "drifting" or uncharted mines could remain outside the heavily monitored shipping lanes. Experts additionally cautioned that mines are only one aspect of the threat facing vessels needing to pass through the strait. With no ceasefire agreement in place and the US announcing what it has described as an "economic D-Day" of sanctions against Iran, the prospect of renewed open warfare remains.

That uncertainty carries a major cost. Since the war began, war-risk insurance costs for ships traversing the waterway have soared from between 1 and 3 percent of a ship's hull value to between 7.5 and 10 percent of hull value, according to a report published by S&P Global in July.

War-risk insurance premiums are probable to remain high, experts say, leaving numerous shipping firms reluctant to resume transiting the Strait of Hormuz. Cheap mines, high cost.

Weeks after the war erupted in late February, Iran's National Defence Council remarked any attempt by "the enemy" to target Iranian coasts or islands would lead to the mining of the Strait of Hormuz.

For a while, it remained unclear whether Tehran was bluffing. Although Iran has never outright confirmed this, but evidence shortly emerged that mines had been deployed.

On May 30, Oman's Maritime Security Centre cautioned shipping operators to exercise caution after an "object suspected to be a floating mine" was sighted near its side of the strait.

Although it could not verify their positions, then, in a June 11 notice, Germany's navy, citing information received from the US and British navies, remarked mines had been noted at four locations around the strait. The UK, France and Germany all deployed warships or mine-countermeasure assets to the region against the backdrop of preparations for feasible mine-clearing operations.

Analysis by the Philadelphia-based Foreign Policy Research Institute (FPRI) has discovered that while sophisticated modern mines can cost in the tens of thousands of dollars to manufacture, imposing economic and strategic measures is anticipated to be far more expensive.

That is since sea mines can cause enormous disruption at a relatively low cost. Suspicion that just one mine may be present in a shipping lane is enough to bring traffic to a halt.

Maritime analysts estimate Iran has a stockpile of between 2, 000 and 6, 000 mines, plenty of of them domestically produced. Scott Savitz, a senior engineer at the research institute RAND. This person specialises in naval operations and technologies, remarked Iran possesses both traditional moored mines and more sophisticated weapons.

While more sophisticated "bottom mines" sit on the seabed and employ sensors to trigger an explosion when they detect a ship's magnetic or acoustic signature above, sea mines can include moored contact mines that detonate when a vessel strikes them.

Iran has "the classic spiky balls that everyone envisions", Savitz remarked. It are mines tethered to an anchor that explode when struck by a ship. "But it additionally has a number of influence mines. These sit on the seabed and are harder to detect." Cleared does not mean risk-free.

Hours after Trump declared the mines cleared from Hormuz on Tuesday, the Joint Maritime Information Center remarked that there remained a "continued risk of drifting or uncharted mines" in and near the strait's traffic separation scheme. According to The UK Maritime Trade Operations Centre, "mine-danger areas" are still active in a post on X. So, who should shipping operators heed?

"The claim that the mines have been cleared came from CENTCOM initially, and in this we can have strong confidence, " he remarked.

Hilborne continued that the US Navy has detonated numerous mines while employing space-based surveillance technology and underwater drones which scan the seabed. US forces have additionally destroyed a number of Iranian naval mine-laying vessels.

But establishing that the main shipping lanes are "clear" is not the same as guaranteeing that every mine has been removed or deactivated. "It is possible that there are a few loose mines, or 'ghost' mines, " Hilborne remarked.

"The claims that the mines have been cleared relate to those that are known to have been deployed in the key lanes, " he continued, explaining that some anchored mines could have broken free.

"It is not particularly likely that there are any in the main shipping lanes due to the level of monitoring, but there may be risks beyond the lanes."

And even if every mine at present known to the US has been destroyed, Iran retains the ability to deploy more. "So while the shipping lanes might currently be clear, that does not mean that the threat has permanently disappeared, " Hilborne remarked.

Mine clearance itself – known as mine countermeasures (MCM) – is a painstaking and dangerous process. Complicating that task, according to the Foreign Policy Research Institute (FPRI), is years of institutional neglect that has weakened the US Navy's dedicated mine-countermeasure capabilities up until shortly before the war began.

While its MH-53E Sea Dragon helicopters – long central to airborne minesweeping operations – were phased out in August, its last four Avenger-class MCM ships in Bahrain were decommissioned in September.

Meanwhile, the US has since relied on a combination of warships and unmanned systems for its Hormuz operation. CENTCOM remarked two guided-missile destroyers additionally entered the strait as the clearance mission began in April, with underwater drones subsequently joining the effort. Why shipping may not return shortly.

Ultimately, the removal of the mines from shipping lanes addresses only part of the calculation faced by shipping operators and insurers.

Notably, a supertanker and its cargo of crude can be worth regarding $300m, meaning war-risk underwriters, oil businesses and tanker operators are probable to demand sustained evidence that passage is safe before sending vessels back through the strait.

"Insurance premiums are likely to remain high, " Hilborne remarked. "These will not come down until there has been a protracted period of calm."

"A single announcement, while welcome, will not bring an immediate drop in the rates."

There are signs, nevertheless, that the shipping industry is adapting to new realities on the water. Alex Almeida, an analyst at maritime intelligence firm Ambrey, informed Al Jazeera that risk aversion among shipping operators appeared to be easing off as alternative arrangements have been developed.

Bloomberg documented earlier this month, for example, that Abu Dhabi National Oil Co's trading arm is offering to shuttle Iraqi oil cargoes through the Strait of Hormuz, with vessels making short trips with their transponders turned off, before transferring cargoes to other ships outside the Gulf. This development comes as the UAE confirmed an indefinite embargo on trade with Iran last week.

"The shuttle service run by the UAE seems to be proving its worth and offloads a lot of the insurance risk from shippers, " Almeida remarked, adding that Saudi Arabia was additionally moving into ship-to-ship transfers and introducing a government-backed insurance scheme.

Almeida remarked the new workarounds available to shippers are increasingly presenting Iran with a dilemma, particularly as US economic pressure increases.

"I think for the first time Iran is under more real pressure than the US, " he remarked. That raises the possibility that Tehran could seek another means of changing the balance of power, he continued, including launching strikes on ship-to-ship transfer areas in the Gulf of Oman. It are within range of Iranian missiles and drones.

Taken together, the developments around why Hormuz remains high risk for ships despite US claims of mine point to a situation that is still moving, and the coming days should bring more clarity.