
Volcano mine system

The M136 Volcano Vehicle-Launched Scatterable Mine System (VLSMS) is a automated mine delivery system developed by the United States Army in the 1980s. The system uses prepackaged mine canisters which contain multiple anti-personnel (AP) and/or anti-tank (AT) mines which are dispersed over a wide area when ejected from the canister. The system, commonly referred to as "Volcano", is also used by other armies around the world.
Overview.
The primary purpose of Volcano is to provide the employing force with the capability to emplace large minefields rapidly under varied conditions. Volcano minefields are ideal for providing flank protection of advancing forces and for operating in concert with air and ground units on flank guard or screen missions.
The system comprises of the M139 Dispenser used for dispensing pre-packaged mine canisters, the dispensing control unit (DCU) and mounting hardware, and is designed to be mounted on either ground or aerial vehicles using the same components except for the mounting hardware, which varies between fitment. Volcano is designed to be fitted to and removed from vehicles with a minimum of time and labour. The dispensing system is also designed for ease of use, to operated by personnel with a minimum of training. The ordnance used by the system is based upon a modified GATOR mine. Both live and inert (training) ordnance is available; live canisters are painted green while inert canisters are painted blue.
When fitted to aircraft, the system is referred to as "Air Volcano" and when fitted to ground vehicles is referred to as "Ground Volcano". The principles and procedures of Volcano minefield emplacement are significantly different for air- and ground-delivery systems; the differences can be summarised as follows:
Air Volcano.
Air Volcano is the fastest method for emplacing large tactical minefields. Although mine placement is not as precise as it is with ground systems, Air Volcano minefields can be placed accurately enough to avoid the danger inherent in minefields delivered by artillery or jet aircraft. Air Volcano is the best form of an obstacle reserve because a minefield can be emplaced in minutes. 
Air Volcano minefield should not be planned or dispensed in areas under enemy observation and fire as the dispensing helicopter is extremely vulnerable to anti-aircraft fire while flying at a steady altitude, speed and flight path required to successfully emplace the minefield. Close coordination between aviation and ground units is required to ensure that Volcano-dispensed mines are emplaced accurately and quickly.
Ground Volcano.
Ground Volcano is designed to emplace large minefields in depth and tactical minefields oriented on enemy forces in support of manoeuvre operations and friendly AT fire. It is ideal for use as an obstacle reserve, employed when enemy forces reach a decision point that indicates future movement. Obstacles can then be emplaced in depth on the avenues the enemy is using, leaving other avenues open for friendly movement.
Ground Volcano is normally employed by combat engineer units. Emplaced minefields are vulnerable to direct and indirect fire, and must be protected when close to the forward line of own troops (FLOT).
Design.
Ordnance.
The Volcano system uses the following live ordnance:
The Volcano system also allows the use of the following inert ordnance:
Mounting Hardware.
The mounting hardware secures the racks to the dispensing vehicle or aircraft, and are specific to each type of dispensing vehicle or aircraft. For aircraft, the racks are equipped with a jettison assembly to release and propel the racks away from the aircraft in case of an emergency. Available mounting racks, listed by vehicle and NATO stock number (NSN), includes:
Operation.
Handling.
Volcano munitions are transported and handled in accordance with regulations for Class V mines and explosives.
Training and Personnel.
Volcano operation requires no special skills as the system is designed for ease of use such that a only a designated rather than dedicated operator is required. Initial operator training will be for familiarisation only with a semi-annual refresher course expected to be sufficient to maintain proficiency. In training operations, the M89 mine canister is replaced with the M88 Practice Mine Canister or M89 Training Canister.
Types of Minefields.
The Volcano system is suitable for emplacing four different types of minefields, each of which has a specific purpose:
Both Air and Ground Volcano are capable of emplacing non-standard minefields i.e. one whose purpose (and therefore layout) does not adhere to the four types described above.
Mine Emplacement.
The Volcano system can emplace a minefield with an average density of 0.72 mines per meter for AT mines and 0.14 mines per meter for AP mines. The densities will vary slightly due to some mines failing to arm and self-destructing two to four minutes after dispensing. There may also be some mines that may not orient correctly when dispensed and not deliver their full blast effect. However, the probability of mines failing the arming sequence or not orienting correctly is relatively small and does not appreciably degrade the minefield lethality. For tracked vehicles entering a Volcano minefield, the AT density yields more than 80 percent probability of the vehicle encountering a mine. 
The number of canisters and vehicles loads required to emplace a minefield depends upon the type of minefield required. "Turn" and "block" minefields are emplaced using the same basic procedures as those used for "disrupt" and "fix" minefields; however, "turn" and "block" minefields use two strips of mines, each strip with twice as many mines. The following table lists the number of mines required for each type of minefield of a given size: 
From Aircraft (Air Volcano).
When fitted to an aircraft, mines are dispensed from the aircraft's flight path. The aircraft flies at a minimum altitude of at speeds ranging from . One aircraft can dispense up to 960 mines per sortie. 
The Air Volcano DCU has a switch to select the aircraft's dispensing speed, with six airspeed settings - 20, 30, 40, 55, 80, and 120 knots. The recommended airspeed for dispersal is 40 knots; higher airspeeds should only be used if absolutely necessary. The time to dispense a load of Volcano munitions depends upon the airspeed as follows:
When emplacing an Air Volcano minefield from a UH-60 Blackhawk helicopter, the door gunner is unable to operate the aircraft's machine gun. Therefore, if the minefield is being emplaced in an area with suspected or reported enemy activity, it is recommended that the Blackhawk is accompanied by an AH-64 Apache to provide suppressing fire if needed.
From Ground Vehicles (Ground Volcano).
For ground vehicles, mines are dispensed from the vehicle at ground speeds of . A constant speed is maintained while the mines are being dispensed so as to attain a consistent mine density. The average time to emplace one load (160 canisters) is 10 minutes. After each load has been dispensed, the vehicle moves out of the minefield and marks the exit. Vehicle must then wait a minimum of 4 minutes before approaching or re-entering the 
minefield to allow faulty mines to self-destruct.
Minefield Marking.
Once laid, minefields are marked to reduce the possibility of fratricide, and in areas with civilian populations, to avoid collateral casualties. Operational doctrine specifies that:
Marking is by way of hazard signs attached to signposts and where appropriate, surrounded by boundary fences constructed from standard fencing materials such as barbed wire, concertina wire and pierced steel planking. Fence sections should be attached to steel or concrete fence posts set sufficiently into the ground to discourage locals from removing them for their own use. Hazard marking begins no less than 20 meters from the outer perimeter of the minefield with warning signs placed at regular intervals outside of the fenced area.
Hazard signs are to be only those approved for U.S. Army use which follow international mine-marking conventions. There are two basic designs for the shape of a hazards sign—square or triangular, each marked with the standardised symbol of a skull and crossbones along with a printed warning of the hazard i.e. "DANGER MINES". When such signs are unavailable, the approved alternative is to use warning signs specifically denoting booby traps or unexploded ordnance (UXO).
Dispenser Vehicles.
The following ground vehicles and aircraft can be used to dispense the Volcano mines: