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M131 Modular Pack Mine System (MOPMS)

DESCRIPTION: The MOPMS is a man-portable anti-tank (AT) and anti-personnel (AP) mine system. The M131 module weighs approximately 165 pounds and contains a mix of 17 M78 AT and four M77 AP mines. This module is stored, shipped and emplaced without any modification to the container. The MOPMS module may be initiated by hardwire or radio control. The hardwire capability uses currently available wire and electrical firing devices. The M71 hand-held radio control unit (RCU) allows one individual to control as many as 15 groups of MOPMS modules from a remote location. The AT mine has a magnetic influence fuse and a Miznay-Schardin kill mechanism. The AP mines deploy four tripwires upon ejection which initiate a fragmenting kill mechanism. Both the AP and AT mines contain a radio frequency receiver which allows the mines to be remotely-controlled (recycle self-destruct time and command destruct) with the RCU once the mines are dispensed. The factory set self-destruct time is four hours.

STATUS: MOPMS fielding is in progress. The U.S. Army Engineer School was the first unit equipped on 6 March 92.

EMPLOYMENT CONCEPT: The MOPMS will be employed to close lanes and gaps in minefields, at chokepoints, to reinforce obstacles, to emplace point minefields and for protective mining. Infantry, Armor, Engineer and other units with a protective mining mission will employ MOPMS in support of their tactical missions in all areas of the battlefield. If the mines are not dispensed from the MOPMS module, they may be recovered and reused. A M71 remote control unit (RCU) or an electronic initiating device, such as the M34 hand-blasting machine connected to the container by field wire, dispenses mines on command. Once dispensed, mines cannot be recovered or reused. Operators can disarm and recover the container for later use, if mines are not dispensed. The RCU can recycle the 4-hour self-destruct time of the mines three times, for a total duration of 16 hours (4 hours after initial launch and three 4-hour recycles). This feature makes it possible to keep the minefield in place for longer periods, if necessary. The RC can also self-destruct mines on command. It allows a unit to counterattack or withdraw through the minefield, as necessary, rather than wait until the self-destruct time has expired. The RCU can control up to 15 containers or groups of containers via separate pulse-coded frequencies, out to 300 to 1,000 meters. Coded frequencies defeat threat electronic counter-measures directed against the system. The M34 50-cap blasting machine can detonate one MOPMS at a maximum range of 3,000 meters. (Internal resistance decreases the maximum range by 400 meters for each additional MOPMS connected in series). When controlled by direct wire, MOPMS dispensers cannot be command-detonated, and the self-destruct time cannot be recycled.

BASIS OF ISSUE: MOPMS will be a Class V item of issue and will be issued to those units that are authorized a basic load of mines. It will be substituted for conventional mines currently in a unit's basic load. The M71 RCU will be a TOE item, issued to Engineer Companies (four RCUs each), Armor, Infantry and Cavalry Companies (two RCUs each), and other selected companies with a protective mining mission (one RCU each).

TRAINING/PERSONNEL: U.S. Army Combat and Combat Support Schools will provide training during basic and advanced courses of instruction on MOPMS employment. At the unit level, training will be primarily conducted using the M136 Training Dispenser and M71 RCU.


    7 dispensing tubes, 21 mines total (17 AT, 4 AP)

    4 hour self destruct time(SD), recycle up to three times (16 hours)

    Mines start to SD at 3 hrs, 12 min (80% of SD time); all mines SD by 4 hrs.

    Mines are propelled 35 meters to the front and sidess

    Mines dispensed by M71 Remote Control Unit (RCU), M32 blasting machine, M34 blasting machine, or M57 Claymore firing device

    Man portable, four man carry, 163 lbs (73 kg) suit case-shaped mine dispenser


    Coverage of small critical targets

    Mission employment:

      *Close lane

      *Deliberate protective minefield (cases emplaced, not dispensed)

      *Nuisance minefield

      *Ambushes and booby traps

      *Tactical minefield with Fix or Disrupt intents

      *In support of MOUT Operations


    Issued as standared Class V munition and drawn from ASP

    Site selection, achieving optimum effect

    Dispensers are arranged in patterns to achieve necessary frontage, depth, and density

    RCU unit can control up to 15 dispensers out to 1 kilometer, can SD all mines on command and recycle the SD time three times

    Recycled mines will start to SD 12 hrs, 48 min; all mines will have SD by 16 hrs

    Mines must be recycled every 3 hrs and 12 min or some will SD before 4 hrs

    Dispensers controlled by blasting machine cannot be recycled mines or command detonated

    Establish trigger points for closing lanes

                Reference FM 20-32, pages 6-31 to 6-34



        Reference FM 20-32, page 6-34


                      Reference FM 20-32, page 6-32


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Page last modified: 07-07-2011 02:45:25 ZULU