Potentially the greatest asset to the IRGC, the mines have amazing area denial possibility, totally cutting off Hormuz from the rest of the world. It also has the potential to deal massive amounts of death to the enemy if an entire ship were to sink because of one. Although the psychological impact of mines are probably the greatest threat, multiple empirical examples from Korea, to Vietnam, to both US-Iraqi wars prove that the mere existence of mines is enough to deter an enemy from certain strategic avenues, or at the least, force them to invest vast amounts of time and money into the mine clearing operations.
Doctrine Mining is traditionally not an offensive weapon, only being used as area denial and weapons of opportunity. However the Iranian strategic doctrine of attrition and a guarantee of a bloody battle in the gulf being used to actively intimidate the GCC and USN, they have transformed the mine into a far more formidable weapon.(.5) The use of the mine as a weapon against the oil shipments of the world fills the role traditionally filled by the airforce and missiles used to crush an opponents infrastructure, Iran can accomplish that much easily this way. It is also an extremely low-risk/high-payoff situation. If the USN does anything less then perform perfectly (which in this case, would entail the prevention of the laying of a single mine) the Iranians win through the mere threat of mining which would prevent shipments from going through and causing the insurance rates on the tankers to jump exponentially, a factor which should not be underestimated. This assumes a best case scenario for the Americans, any worse and Iran could easily win a symbolic(which is ultimately what matters in this generation of warfare) by bloodying the Americas nose in much the same way as the 2006 war between Israel and Lebanon. The targets in any war would be both US and GCC naval vessels as well as civilian tankers belonging to enemy nations, each presenting particular tactical gains if hit. Tankers would be an easy target, soft skinned and large they would easily be hit by the mines, knocking them out of commission would put pressure on the US to end the conflict quickly and accept a peace treaty. The following spikes in oil prices would seriously damage the GCC.(.75) Attacking naval vessels would be a great boon in psychological warfare, not only would it boost Iran's credibility as having struck a mightily blow against the USN, but it would no doubt anger the domestic US population who would heartily reject getting drawn into another nebulous war in Iran after the Iraq and Afghanistan experiences. It would also simply reduce the US warfighting capability in the region and in the zero-sum game that is war, would increase Iran's relative strength.
The Mines The Iranian stock of sea mines is estimated to be around 5,000, putting them in 4th place worldwide. The majority of the stock are Chinese in design. 1,000 of those mines are EM-11, EM-31 and EM-52(assuming an even split of around 300 for each class). The EM-52 is the most devastating because it rests on the bottom of the sea floor then shoots out at the target at enormous speeds before detonating next to the target, meaning it doesn’t have to rely on the ‘bubble effect’ to injure the vessel.(1)
EM-11 Type: Seabed Fuse: Acoustic, magnetic, pressure Warhead: 300 kg Depth: 5-30 m Other: Includes counter and delay timer Originating in China, the EM-11 is anchored to the sea-floor. Its maximum operating depth of 30 m means that its use would be restricted to Iran's immediate coast line, particularly near its border with Iraq in the north. Although it is possible that they could be deployed in the shallow waters surrounding the gulf countries, but this would be much harder to accomplish. The EM-11 is fairly hard to detect by virtue of it being a bottom mine
EM-31(2) Type: Moored Fuse: Probably acoustic, pressure and magnetic, very small probability of optical Depth: <200 m A moored mine also from China, the EM-31 is a low-tech device that is easily cleared and that is really only useful for are denial operations. That being said, they are easy to deploy and are cheap to build. It can be used in the straits.
EM-52(3) Type: Rocket Rising Fuse: Presumably Acoustic, and pressure Warhead: 140 kg Depth: 110 m max Range: 3,400 m Other: Includes counter and delay timer. Four can be laid at a time by a missile boat. The most advanced and feared of Iran's mines, the EM-52 sits on the seafloor until its fuse is tripped, it then uses a rocke to rise rapidly and detonate right below the hull of the target. Its litany of fuse options make it VERY hard to sweep for. M-08 (4) Type: Moored Fuse: Contact, acoustic, magnetic, pressure Warhead: 115 kg Depth: 110 m Other: North Koreas origin Like the EM-31, this is a low-tech area-denial weapon that is fairly easy to sweep for. However they are a step above the EM-31's in that they have been improved by the addition of influence sensors.(5)
MDM-6 (6) Type: Seabed Fuse: magnetic, acoustic and pressure Warhead: 1100 kg Depth:12-120 Other: Deployed via Ghadir. Timer and counter