ISC Defence Intelligence
BLU-91/B Anti-Tank Mine Deployment via GATOR System: First US Scatterable Mine Combat Employment in 35 Years
Scatterable mines are routinely characterised as precision area-denial tools with reliable self-destruct mechanisms — but the reported deployment of BLU-91/B mines near Shiraz reveals persistent hazards that self-destruct timers alone cannot eliminate, and reintroduces a weapon class the US military had quietly set aside since 1991.
Technical Summary
On 31 March 2026, multiple open-source reports confirmed that US forces deployed BLU-91/B anti-tank mines via air delivery near Shiraz in southern Iran. The mines were reportedly scattered approximately three miles from an Iranian ballistic missile facility, with the stated operational objective of restricting the movement of Iranian mobile missile transporter-erector-launchers (TELs).
The delivery system is assessed as the CBU-89/B GATOR, a US air-delivered scatterable mine-laying system comprising a SUU-64/B tactical munitions dispenser loaded with a mixed payload of 72 BLU-91/B anti-tank mines and 22 BLU-92/B anti-personnel mines. The CBU-89/B is dispensed from tactical aircraft at altitudes between 60 and 600 metres (200–2,000 ft) and disperses mines across an elliptical pattern approximately 230 metres wide by 700 metres long per dispenser. Each BLU-91/B contains approximately 580 g of Composition H-6 (RDX/TNT/aluminium/wax 45/30/20/5) as the main explosive charge.
This deployment marks the first confirmed US combat employment of scatterable anti-tank mines since Operation Desert Storm in 1991 — a 35-year operational hiatus. Iran’s ISNA news agency reported at least one civilian casualty and several injuries from devices described as “explosives shaped like metal cans,” a description consistent with the cylindrical form factor of the BLU-91/B.
BLU-91/B Anti-Tank Mine — Technical Parameters
Designation: BLU-91/B (GATOR Anti-Tank Mine)
Design intention: Anti-vehicular; track-breaking and belly-attack
Explosive fill: ~580 g Composition H-6 (RDX/TNT/Al/wax)
Initiation: Magnetic influence fuze; activates on vehicle magnetic signature
All-up mass: ~1.8 kg (4 lb)
Hazard Division: HD 1.1 D (mass detonation hazard, secondary detonating substance)
Self-destruct: Battery-powered timer; 4-hour or 48-hour settings
Self-deactivation: Battery depletion backup (~15 days per MIL-STD-1718)
Delivery system: CBU-89/B GATOR (SUU-64/B dispenser; 72 AT + 22 AP mines per unit)
Analysis of Effects
Blast and Target-Defeat Assessment
The BLU-91/B is designed to defeat light armoured and wheeled vehicles through track-breaking and underbody blast. The 580 g H-6 charge produces an estimated peak overpressure of approximately 1,400 kPa (203 psi) at 0.5 metres. Against an unarmoured vehicle or TEL transporter, this is sufficient to destroy the wheel assembly and disable the vehicle. Against main battle tank (MBT) tracks, the charge is designed to sever one or more track links, achieving a mobility kill.
The anti-personnel companion mine, the BLU-92/B, contains approximately 170 g of Composition A-5 with a tripwire-activated fragmentation sleeve. Fragment Dangerous Distance (FDD) for the BLU-92/B is assessed at approximately 20 metres. If the reported mixed deployment included both mine types, the combined field presents hazards to both vehicular traffic and dismounted personnel.
Self-Destruct Reliability and Residual Hazard
The BLU-91/B incorporates a battery-powered self-destruct mechanism with selectable delay settings of 4 hours or 48 hours. A secondary self-deactivation feature relies on battery depletion to render the firing circuit inert within approximately 15 days. US policy requires scatterable mines to have self-destruct reliability exceeding 99%, corresponding to a dud rate below 1%. However, operational data from testing suggests actual field dud rates may range from 1% to 5% depending on terrain, drop altitude, and environmental conditions.
A single CBU-89/B dispenser deploys 94 mines. At a 2% dud rate, approximately two mines per dispenser may fail to self-destruct, persisting as Explosive Remnants of War (ERW). If multiple dispensers were employed, the cumulative residual hazard across the mined area could include dozens of live, armed mines with no external indication of their failed self-destruct status.
Personnel and Safety Considerations
Explosive Ordnance Disposal (EOD) and mine clearance personnel approaching a GATOR minefield face a complex threat environment. The BLU-91/B magnetic influence fuze is sensitive to ferrous objects, requiring all clearance operations to use non-magnetic detection and approach protocols. Conventional metallic mine detectors and armoured clearance vehicles may trigger the magnetic fuze at standoff distances.
Cordon and Evacuation Distance (CED) for individual BLU-91/B mines is assessed at a minimum of 100 metres for unprotected personnel, consistent with the combined blast and fragmentation hazard of the 580 g H-6 charge. For the mixed AT/AP field including BLU-92/B, the tripwire initiation mechanism adds an additional approach hazard requiring visual sweep before any physical approach.
Self-destruct failure assessment presents a particular challenge: there is no external indicator distinguishing a mine with a functioning self-destruct timer from one with a failed timer. Post-self-destruct clearance operations must therefore treat all mines as potentially live until each is individually confirmed safe by EOD personnel.
Data Gaps
DATA GAP: Number of dispensers employed — Open-source reporting confirms BLU-91/B deployment but does not specify the number of CBU-89/B dispensers used. This parameter is critical for estimating the total mine count, the minefield footprint, and the residual ERW burden.
DATA GAP: Self-destruct timer setting — Whether the 4-hour or 48-hour self-destruct setting was selected is not confirmed. The shorter setting reduces the persistent hazard window but may be insufficient if the area-denial objective requires sustained coverage.
DATA GAP: AP mine inclusion — Whether the deployment included BLU-92/B anti-personnel mines alongside BLU-91/B anti-tank mines is not confirmed from open sources. The standard CBU-89/B loadout includes both types, but selective loading is technically feasible.
DATA GAP: Civilian casualty verification — Iranian state media reports of civilian casualties have not been independently verified. The description of “metal cans” is consistent with BLU-91/B form factor but could also describe other ordnance types.
Corrections & updates welcome. If you hold open-source data that refines or corrects any parameter in this article, please contact [email protected] citing the specific claim and your source. Verified corrections will be incorporated and credited in the revision history.
Sources & References
- [1] Seoul Economic Daily, “U.S. Deploys Anti-Tank Mines for First Time in 35 Years,” 31 March 2026. [B/2]
- [2] Amnesty International, statement on scatterable mine deployment, March 2026. [B/2]
- [3] US Army, FM 20-32, Mine/Countermine Operations, Department of the Army. [A/1]
- [4] MIL-STD-1718, Requirements for Self-Destruct and Self-Deactivation of Scatterable Mines. [A/1]
- [5] NATO, AASTP-1: Manual of NATO Safety Principles for the Storage of Military Ammunition and Explosives. [A/1]
- [6] DSA 03.OME, Defence OME Safety and Environmental Management, UK Ministry of Defence. [A/1]