undercharged mine

from The Collaborative International Dictionary of English v.0.48

Undercharge \Un`der*charge"\, v. t.
   1. To charge below or under; to charge less than is usual or
      suitable for; as, to undercharge goods or services.
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   2. To put too small a charge into; as, to undercharge a gun.
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   {Undercharged mine} (Mil.), a mine whose crater is not as
      wide at top as it is deep. --W. P. Craighill.
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